[ { "id": "authors:733az-vxd70", "collection": "authors", "collection_id": "733az-vxd70", "cite_using_url": "https://authors.library.caltech.edu/records/733az-vxd70", "type": "article", "title": "2-D Flexible Phased Array Shape Reconstruction", "author": [ { "family_name": "Mizrahi", "given_name": "Oren S.", "orcid": "0000-0003-4271-8822" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "

Flexible phased arrays can address new applications and provide new capabilities in communications, radar, sensing, and wireless power transfer due to their novel form factor, which enables rapid deployment, conformity, and mass and size advantages. However, the variable position of their elements makes them vulnerable to the deleterious effects of incoherence. This problem can be addressed by reconstructing the shape of the array and compensating for the change in the position of the radiator at the system level. This article presents a method for reconstructing the shape of a 2-D flexible phased array using only measurements of mutual coupling between the array elements. The method consists of an optimization loop: predicting the coupling for a given shape, comparing the prediction to measurement, and iterating through shape perturbations using the Levenberg–Marquardt algorithm. Shape reconstruction is demonstrated with a ≈0.08 λ mean position error across a wide variety of shape configurations on a passive 8×8 flexible patch antenna array operating at ≈5 GHz.

", "doi": "10.1109/tmtt.2025.3649052", "issn": "0018-9480", "publisher": "IEEE", "publication": "IEEE Transactions on Microwave Theory and Techniques", "publication_date": "2026-04", "series_number": "4", "volume": "74", "issue": "4", "pages": "3870-3888" }, { "id": "authors:fa161-eey24", "collection": "authors", "collection_id": "fa161-eey24", "cite_using_url": "https://authors.library.caltech.edu/records/fa161-eey24", "type": "article", "title": "Space solar power generation: A viable system proposal and technoeconomic analysis", "author": [ { "family_name": "Mizrahi", "given_name": "Oren S.", "orcid": "0000-0003-4271-8822" }, { "family_name": "Jahelka", "given_name": "Phillip", "orcid": "0000-0002-1460-7933" }, { "family_name": "Gdoutos", "given_name": "Eleftherios", "orcid": "0000-0003-3529-4726", "clpid": "Gdoutos-Eleftherios-E" }, { "family_name": "Brunet", "given_name": "Jesse", "orcid": "0009-0002-8614-3362" }, { "family_name": "Ayling", "given_name": "Alex", "orcid": "0009-0008-5440-7785" }, { "family_name": "Fikes", "given_name": "Austin", "orcid": "0000-0003-4889-5782" }, { "family_name": "Wu", "given_name": "Ailec" }, { "family_name": "Madonna", "given_name": "Richard", "orcid": "0000-0002-8191-4896" }, { "family_name": "Atwater", "given_name": "Harry A.", "orcid": "0000-0001-9435-0201", "clpid": "Atwater-H-A" }, { "family_name": "Pellegrino", "given_name": "Sergio", "orcid": "0000-0001-9373-3278", "clpid": "Pellegrino-S" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper presents a distributed space solar power system that converts solar insolation into microwave power and beams it to Earth. This system, composed of a power station of close-flying modules residing in geostationary orbit, can form dynamically programmable focal points on Earth to provide dispatchable power on demand. Modules are composed of flexible phased array sheets hosting a self-synchronizing network of integrated circuits and antennas that convert DC power from photovoltaic cells into radiated RF energy. The sheets are coiled into a compact payload, launched, and deployed in orbit. Here, we present a detailed technoeconomic analysis of the proposed system, with investigations into mass, cost to produce and launch, and a levelized cost of energy (LCOE). Our analyses demonstrate that with 10 years of technology development, maturation, and scaling, the proposed 10 GHz system can deliver electricity at 9.4 \u00a2/kWh\u2014competitive with the cheapest clean energy sources available today.", "doi": "10.1016/j.joule.2025.101928", "issn": "2542-4785", "publisher": "Cell Press", "publication": "Joule", "publication_date": "2025-06-18", "series_number": "6", "volume": "9", "issue": "6", "pages": "101928" }, { "id": "authors:46qzv-gkr66", "collection": "authors", "collection_id": "46qzv-gkr66", "cite_using_url": "https://authors.library.caltech.edu/records/46qzv-gkr66", "type": "article", "title": "Phase Noise and Dynamic Range in Radar Arrays", "author": [ { "family_name": "Nooshabadi", "given_name": "Samir", "orcid": "0000-0003-1645-0009", "clpid": "Nooshabadi-Samir" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "In this work, the phase noise-induced sidelobes that limit radar dynamic range are analyzed. An analytical framework that maps circuit-level parameters to a stochastic model of local oscillator phase noise in a radar array is developed. The model is used to analytically predict phase noise-induced sidelobes for a variety of radar configurations. The effects of range-Doppler-spatial processing are quantified and related to code-dependent parameters for FMCW and PMCW radars. Analytical expressions are verified with time-domain stochastic simulations, rigorously defined using the theory of stochastic differential equations. A link budget example for an automotive MIMO radar is provided, demonstrating the utility of the analytical framework in determining the required local oscillator phase noise for a desired radar dynamic range.", "doi": "10.1109/tcsi.2025.3526365", "issn": "1549-8328", "publisher": "IEEE", "publication": "IEEE Transactions on Circuits and Systems I: Regular Papers", "publication_date": "2025", "pages": "1-14" }, { "id": "authors:rtjvn-axy10", "collection": "authors", "collection_id": "rtjvn-axy10", "cite_using_url": "https://authors.library.caltech.edu/records/rtjvn-axy10", "type": "article", "title": "Wireless power transfer in space using flexible, lightweight, coherent arrays", "author": [ { "family_name": "Ayling", "given_name": "Alex", "orcid": "0009-0008-5440-7785", "clpid": "Ayling-Alex-E" }, { "family_name": "Fikes", "given_name": "Austin", "orcid": "0000-0003-4889-5782", "clpid": "Fikes-Austin-C" }, { "family_name": "Mizrahi", "given_name": "Oren S.", "orcid": "0000-0003-4271-8822", "clpid": "Mizrahi-Oren-S" }, { "family_name": "Wu", "given_name": "Ailec", "orcid": "0009-0008-7726-7842", "clpid": "Wu-Ailec" }, { "family_name": "Riazati", "given_name": "Raha", "orcid": "0009-0009-8544-8288" }, { "family_name": "Brunet", "given_name": "Jesse", "orcid": "0009-0002-8614-3362", "clpid": "Brunet-Jesse" }, { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-Behrooz" }, { "family_name": "Bohn", "given_name": "Florian", "orcid": "0000-0002-4619-378X", "clpid": "Bohn-Florian" }, { "family_name": "Gal-Katziri", "given_name": "Matan", "orcid": "0000-0001-9100-1188" }, { "family_name": "Hashemi", "given_name": "Mohammed Reza M.", "orcid": "0000-0002-8908-0048", "clpid": "Hashemi-Mohammed-R" }, { "family_name": "Padmanabhan", "given_name": "Sharmila", "orcid": "0000-0002-4579-7426" }, { "family_name": "Russell", "given_name": "Damon" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "

Space solar power (SSP), envisioned for decades as a solution for continuous, stable, and dynamically dispatchable clean energy, has seen tremendous interest and a number of experimental demonstrations in the last few years. A practical implementation has been elusive to date, owing to the high launch costs associated with heavy, rigid photovoltaic and wireless power transfer (WPT) arrays. Lightweight and flexible solutions for WPT have been demonstrated terrestrially but, to date, have not been deployed and tested in space. In this paper, we present an experimental space demonstration of a lightweight, flexible WPT array powered by custom radio-frequency integrated circuits. The transmit arrays, receive arrays, and the rest of the system were operated and tested for eight months in Low Earth Orbit (LEO). Results from these experiments, including pointing of the array’s beam to Earth and its detection by a ground station, are presented and discussed in detail. Observations and results from this mission uncover existing strengths and weaknesses that inform future steps towards realizing SSP.

", "doi": "10.1016/j.actaastro.2024.08.006", "issn": "0094-5765", "publisher": "Elsevier", "publication": "Acta Astronautica", "publication_date": "2024-11", "volume": "224", "pages": "226-243" }, { "id": "authors:gxpw6-h8w18", "collection": "authors", "collection_id": "gxpw6-h8w18", "cite_using_url": "https://authors.library.caltech.edu/records/gxpw6-h8w18", "type": "conference_item", "title": "An integrated photonic-electronic quantum coherent receiver for sub-shot-noise-limited optical links", "book_title": "Optical Fiber Communication Conference (OFC) 2024", "author": [ { "family_name": "Gurses", "given_name": "Volkan", "orcid": "0000-0001-8184-208X", "clpid": "Gurses-Volkan" }, { "family_name": "Sarkar", "given_name": "Debjit", "orcid": "0000-0002-3066-9819", "clpid": "Sarkar-Debjit" }, { "family_name": "Davis", "given_name": "Samantha", "orcid": "0000-0001-9994-8165", "clpid": "Davis-Samantha-I" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "

We demonstrate an integrated quantum-limited coherent receiver with co-packaged silicon photonics and electronics. The fully integrated receiver has 2.57 GHz bandwidth, 14.5 dB shot noise clearance, 587 µW knee power, and 2.7 × 0.8 mm2 footprint. With this system, we measure squeezed vacuum showing 0.156 ± 0.039 dB sub-shot-noise-level sensitivity.

", "doi": "10.1364/ofc.2024.tu2c.1", "isbn": "978-1-957171-32-6", "publisher": "Optica Publishing Group", "place_of_publication": "Washington, DC", "publication_date": "2024-03", "pages": "Tu2C.1" }, { "id": "authors:1n72w-zmh46", "collection": "authors", "collection_id": "1n72w-zmh46", "cite_using_url": "https://authors.library.caltech.edu/records/1n72w-zmh46", "type": "conference_item", "title": "Analyzing the Performance of Phased Array Geometries with Aperture Projection Analysis", "book_title": "2024 18th European Conference on Antennas and Propagation (EuCAP)", "author": [ { "family_name": "Williamstyer", "given_name": "D. Elliott", "orcid": "0000-0002-6213-4712", "clpid": "Williamstyer-D-Elliott" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "
\n
\n
\n
Geometry plays an important role in phased array performance. There is thus an opportunity to improve array performance by including geometry as a design variable. This is the core idea in the emerging field of shape-changing phased arrays. Therefore, formal analytic tools are needed for assessing the performance of different geometries. This work establishes a solid theoretical foundation for a commonly used analysis technique, aperture projection analysis. Using this tool, the fundamental trade-offs between gain and steering range for common array geometries are explored. Analytic formulas of the maximum gain are established and numeric calculations directly compare the relationship between maximum gain and steering range. It is demonstrated that planar arrays have the highest gain, that spherical and cylindrical arrays have the highest steering range, and conic arrays offer the best compromise.
\n
\n
\n
", "doi": "10.23919/eucap60739.2024.10500967", "isbn": "978-88-31299-09-1", "publisher": "IEEE", "place_of_publication": "Glasgow, UK", "publication_date": "2024-03", "pages": "1-5" }, { "id": "authors:gbhxy-z6j32", "collection": "authors", "collection_id": "gbhxy-z6j32", "cite_using_url": "https://authors.library.caltech.edu/records/gbhxy-z6j32", "type": "article", "title": "Visible spectrum waveguiding in bulk CMOS", "author": [ { "family_name": "Sarkar", "given_name": "Debjit", "orcid": "0000-0002-3066-9819", "clpid": "Sarkar-Debjit" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Waveguiding across the visible spectrum in an unmodified bulk CMOS chip is reported. The chip is fabricated in a standard CMOS process, and a simple wet etch removes metal in predetermined locations to expose glass rib waveguides. A modified Euler bend is introduced to improve bend radii by nearly an order of magnitude in the rib waveguides, and upper-bound losses are measured at visible wavelengths. These losses range from 6.2 dB/cm at 450 nm to 3.2 dB/cm at 650 nm and represent the lowest losses reported at visible wavelengths in unmodified bulk CMOS.", "doi": "10.1364/oe.502252", "issn": "1094-4087", "publisher": "Optica Publishing Group", "publication": "Optics Express", "publication_date": "2023-12-04", "series_number": "25", "volume": "31", "issue": "25", "pages": "42365-42372" }, { "id": "authors:r0r2c-wzz55", "collection": "authors", "collection_id": "r0r2c-wzz55", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230404-448520900.2", "type": "article", "title": "A 28-GHz, Multi-Beam, Decentralized Relay Array", "author": [ { "family_name": "Nooshabadi", "given_name": "Samir", "orcid": "0000-0003-1645-0009", "clpid": "Nooshabadi-Samir" }, { "family_name": "Khial", "given_name": "Parham P.", "orcid": "0000-0002-3242-8541", "clpid": "Khial-Parham-P" }, { "family_name": "Fikes", "given_name": "Austin", "orcid": "0000-0003-4889-5782", "clpid": "Fikes-Austin" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Multi-beam relays can be used to overcome the non-line-of-sight (NLOS) issues in millimeter-wave (mm-wave) communication networks that serve many users in an obstruction-rich environment. We demonstrate a modular multi-beam relay array at 28 GHz, which is scalable and fully decentralized. The individual branches of the array are independent and do not need to share a timing reference or be physically located on the same substrate. Multi-beam capability is facilitated by a multi-channel baseband signal conditioning chain that includes a reconfigurable, passive, inductorless, 3rd-order N-path filter with programmable frequency-independent phase shift. This baseband signal conditioning chain enables beams concurrently multiplexed in spatial and frequency domains. We present the theory, design, and operation of the custom RFIC, which enables independent multi-beam relaying. Multiple RFICs are used to create relay arrays. A four-element relay array demonstrates three independently steered beams that utilize the full array aperture with a total wireless throughput of 625 Mb/s.", "doi": "10.1109/jssc.2023.3251898", "issn": "0018-9200", "publisher": "IEEE", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2023-05", "series_number": "5", "volume": "58", "issue": "5", "pages": "1212-1227" }, { "id": "authors:7cfpe-ncf36", "collection": "authors", "collection_id": "7cfpe-ncf36", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230526-663080000.38", "type": "book_section", "title": "Wireless Power Transfer at Distance", "book_title": "2023 IEEE Custom Integrated Circuits Conference (CICC)", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Wireless revolution in communication systems over the last several decades is beginning to move to the realm of energy transfer. Continuous energy transmission using proximity inductive charging is already available in many of our portable device [1]. Although it is technically wireless, the source and recipient of the energy still need to be within immediate proximity of each other, which leaves most of the wireless power application space unaddressed. This need drives the development of wireless power transfer at distance (WPT-AD) [2].", "doi": "10.1109/cicc57935.2023.10121222", "isbn": "979-8-3503-9948-6", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2023-04", "pages": "1-4" }, { "id": "authors:hqf4a-33j52", "collection": "authors", "collection_id": "hqf4a-33j52", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220712-193859173", "type": "article", "title": "Large-Scale Crosstalk-Corrected Thermo-Optic Phase Shifter Arrays in Silicon Photonics", "author": [ { "family_name": "Gurses", "given_name": "B. Volkan", "orcid": "0000-0001-8184-208X", "clpid": "Gurses-B-Volkan" }, { "family_name": "Fatemi", "given_name": "Reza", "orcid": "0000-0001-9081-2608", "clpid": "Fatemi-Reza" }, { "family_name": "Khachaturian", "given_name": "Aroutin", "orcid": "0000-0001-8304-3302", "clpid": "Khachaturian-Aroutin" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "We introduce a thermo-optic phase shifter (TOPS) array architecture with independent phase control of each phase shifter for large-scale and high-density photonic integrated circuits with two different control schemes: pulse amplitude modulation (PAM) and pulse width modulation (PWM). We realize a compact spiral TOPS and a 288-element high-density row-column TOPS array with this architecture and drive TOPS with waveforms of both control schemes and of different array sizes. We present a thermal excitation model and a finite difference method-based simulation to simulate large-scale TOPS arrays and compare both schemes experimentally and theoretically. We also analyze the effects of thermal crosstalk in the realized TOPS array and implement a thermal crosstalk correction algorithm with the developed model. The high-density TOPS array architecture and the thermal crosstalk correction algorithm pave the way for high-density TOPS arrays with independent phase control in large-scale photonic integrated circuits interfaced with electronics limited in voltage swing and bandwidth.", "doi": "10.1109/JSTQE.2022.3189965", "issn": "1077-260X", "publisher": "IEEE", "publication": "IEEE Journal of Selected Topics in Quantum Electronics", "publication_date": "2022-11", "series_number": "6", "volume": "28", "issue": "6", "pages": "Art. No. 6101009" }, { "id": "authors:pwga6-esn60", "collection": "authors", "collection_id": "pwga6-esn60", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20221024-123751900.4", "type": "article", "title": "Flexible active antenna arrays", "author": [ { "family_name": "Gal-Katziri", "given_name": "Matan", "orcid": "0000-0001-9100-1188", "clpid": "Gal-Katziri-M" }, { "family_name": "Fikes", "given_name": "Austin", "orcid": "0000-0003-4889-5782", "clpid": "Fikes-Austin" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Complex and dynamic control of radiated fields are advantageous for flexible radio systems, which naturally move, roll, bend, twist, deform, and vibrate. Practical challenges hinder the proliferation of these antenna arrays. This work shows how using radio-frequency microchips reduces system component count, decreases mass to ~0.1\u2009g cm\u207b\u00b2, and increases functionality and mechanical flexibility. We develop a general platform for large scale flexible arrays and demonstrate two different 256-elements, 30\u2009\u00d7\u200930\u2009cm\u00b2 flexible arrays. By varying supply distribution methods and radiators we show how performance can be optimized for maximum power delivery or physical flexibility. The demonstrated systems conform to curved surfaces with radii of curvatures as low as 23\u2009cm and wirelessly deliver\u2009~\u200980\u2009mW of DC power to a 6.7\u2009cm\u2009\u00d7\u200911\u2009cm-receiver over one meter away. This paves the way towards the integration of smart arrays in flexible wearables and deployable lightweight airborne systems.", "doi": "10.1038/s41528-022-00218-z", "issn": "2397-4621", "publisher": "Nature Publishing Group", "publication": "npj Flexible Electronics", "publication_date": "2022-10-14", "volume": "6", "pages": "Art. No. 85" }, { "id": "authors:k030e-vmy62", "collection": "authors", "collection_id": "k030e-vmy62", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220121-11752000", "type": "article", "title": "Optically Synchronized Phased Arrays in CMOS", "author": [ { "family_name": "Gal-Katziri", "given_name": "Matan", "orcid": "0000-0001-9100-1188", "clpid": "Gal-Katziri-Matan" }, { "family_name": "Ives", "given_name": "Craig", "clpid": "Ives-Craig-E" }, { "family_name": "Khakpour", "given_name": "Armina", "clpid": "Khakpour-Armina" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Optical synchronization of large-span arrays offers significant benefits over electrical methods in terms of the weight, cost, power dissipation, and complexity of the clock distribution network. This work presents the analysis and design of the first phased array transmitter synchronized using a fully monolithic CMOS optical receiver. We demonstrate a bulk CMOS, 8-element, 28-GHz phased array building block with an on-chip photodiode (PD) that receives and processes the optical clock and uses an integrated PLL to generate eight independent phase-programmable RF outputs. The system demonstrates beam steering, data transmission, and remote synchronization of array elements at 28 GHz with fiber lengths up to 25 m, in order to show the scaling benefits of our approach. The provision of small footprint and cost-effective CMOS transceivers with integrated optoelectronic receivers enables exciting opportunities for low-cost and ultralight array systems.", "doi": "10.1109/jssc.2021.3136787", "issn": "0018-9200", "publisher": "IEEE", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2022-06", "series_number": "6", "volume": "57", "issue": "6", "pages": "1578-1593" }, { "id": "authors:2gnm1-e1692", "collection": "authors", "collection_id": "2gnm1-e1692", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220719-954621100", "type": "article", "title": "Discretization of annular-ring diffraction pattern for large-scale photonics beamforming", "author": [ { "family_name": "Khachaturian", "given_name": "Aroutin", "orcid": "0000-0001-8304-3302", "clpid": "Khachaturian-Aroutin" }, { "family_name": "Fatemi", "given_name": "Reza", "orcid": "0000-0001-9081-2608", "clpid": "Fatemi-Reza" }, { "family_name": "Darbinian", "given_name": "Artsroun", "clpid": "Darbinian-Artsroun" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A solid-state active beamformer based on the annular-ring diffraction pattern is demonstrated in an integrated photonic platform. Such a circularly symmetric annular-ring aperture achieves a radiating element limited field of view. Furthermore, it is demonstrated that a multi-annular-ring aperture with a fixed linear density of elements maintains the beam efficiency for larger apertures while reducing the beamwidth and side-lobe level. A 255-element multi-annular-ring optical phased array with active beamforming is implemented in a standard photonics process. A total of 510 phase and amplitude modulators enable beamforming and beam steering using this aperture. A row\u2013column drive methodology reduces the required electrical drivers by more than a factor of 5.", "doi": "10.1364/prj.443061", "issn": "2327-9125", "publisher": "Optica Publishing Group", "publication": "Photonics Research", "publication_date": "2022-05-01", "series_number": "5", "volume": "10", "issue": "5", "pages": "1177-1186" }, { "id": "authors:dqda3-kkd62", "collection": "authors", "collection_id": "dqda3-kkd62", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220727-412689800", "type": "article", "title": "Achieving full grating-lobe-free field of view with low-complexity co-prime photonic beamforming transceivers", "author": [ { "family_name": "Khachaturian", "given_name": "Aroutin", "orcid": "0000-0001-8304-3302", "clpid": "Khachaturian-Aroutin" }, { "family_name": "Fatemi", "given_name": "Reza", "orcid": "0000-0001-9081-2608", "clpid": "Fatemi-Reza" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Integrated photonic active beamforming can significantly reduce the size and cost of coherent imagers for LiDAR and medical imaging applications. In current architectures, the complexity of photonic and electronic circuitry linearly increases with the desired imaging resolution. We propose a novel photonic transceiver architecture based on co-prime sampling techniques that breaks this trade-off and achieves the full (radiating-element-limited) field of view (FOV) for a 2D aperture with a single-frequency laser. Using only order-of-N radiating elements, this architecture achieves beamwidth and sidelobe level (SLL) performance equivalent to a transceiver with order-of-N\u00b2 elements with half-wavelength spacing. Furthermore, we incorporate a pulse amplitude modulation (PAM) row\u2013column drive methodology to reduce the number of required electrical drivers for this architecture from order of N to order of \u221aN. A silicon photonics implementation of this architecture using two 64-element apertures, one for transmitting and one for receiving, requires only 34 PAM electrical drivers and achieves a transceiver SLL of \u221211.3\u2009dB with 1026 total resolvable spots, and 0.6\u00b0 beamwidth within a 23\u00b0\u00d716.3\u00b0 FOV.", "doi": "10.1364/prj.437518", "issn": "2327-9125", "publisher": "Optica Publishing Group", "publication": "Photonics Research", "publication_date": "2022-05", "series_number": "5", "volume": "10", "issue": "5", "pages": "A66-A73" }, { "id": "authors:7c5qy-6gj46", "collection": "authors", "collection_id": "7c5qy-6gj46", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220324-224059015", "type": "article", "title": "Foundry-fabricated grating coupler demultiplexer inverse-designed via fast integral methods", "author": [ { "family_name": "Sideris", "given_name": "Constantine", "orcid": "0000-0002-3042-4889", "clpid": "Sideris-Constantine" }, { "family_name": "Khachaturian", "given_name": "Aroutin", "orcid": "0000-0001-8304-3302", "clpid": "Khachaturian-Aroutin" }, { "family_name": "White", "given_name": "Alexander D.", "orcid": "0000-0002-5387-310X", "clpid": "White-Alexander-D" }, { "family_name": "Bruno", "given_name": "Oscar P.", "orcid": "0000-0001-8369-3014", "clpid": "Bruno-O-P" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Silicon photonics is an emerging technology which, enabling nanoscale manipulation of light on chips, impacts areas as diverse as communications, computing, and sensing. Wavelength division multiplexing is commonly used to maximize throughput over a single optical channel by modulating multiple data streams on different wavelengths concurrently. Traditionally, wavelength (de)multiplexers are implemented as monolithic devices, separate from the grating coupler, used to couple light into the chip. This paper describes the design and measurement of a grating coupler demultiplexer\u2014a single device which combines both light coupling and demultiplexing capabilities. The device was designed by means of a custom inverse design algorithm which leverages boundary integral Maxwell solvers of extremely rapid convergence as the mesh is refined. To the best of our knowledge, the fabricated device enjoys the lowest insertion loss reported for grating demultiplexers, small size, high splitting ratio, and low coupling-efficiency imbalance between ports, while meeting the fabricability constraints of a standard UV lithography process.", "doi": "10.1038/s42005-022-00839-w", "issn": "2399-3650", "publisher": "Nature Publishing Group", "publication": "Communications Physics", "publication_date": "2022-03-23", "volume": "5", "pages": "Art. No. 68" }, { "id": "authors:44ft3-jg113", "collection": "authors", "collection_id": "44ft3-jg113", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220217-686367000", "type": "book_section", "title": "Fully Collapsible Lightweight Dipole Antennas", "book_title": "2021 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (APS/URSI)", "author": [ { "family_name": "Fikes", "given_name": "Austin", "orcid": "0000-0003-4889-5782", "clpid": "Fikes-Austin-C" }, { "family_name": "Mizrahi", "given_name": "Oren S.", "orcid": "0000-0003-4271-8822", "clpid": "Mizrahi-Oren-S" }, { "family_name": "Truong", "given_name": "Alan", "clpid": "Truong-Alan" }, { "family_name": "Wiesem\u00fcller", "given_name": "Fabian", "clpid": "Wiesem\u00fcller-Fabian" }, { "family_name": "Pellegrino", "given_name": "Sergio", "orcid": "0000-0001-9373-3278", "clpid": "Pellegrino-S" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Flexible, deployable phased arrays enable novel and diverse applications but necessitate similarly flexible radiators. Here we present a light and flexible 10GHz dipole antenna, which is co-cured to a glass-fiber composite and suited for flexible phased arrays. The antennas are designed to dynamically conform to new array shapes and be flexible enough to fold completely flat and pop back up upon deployment. We employ a pop-up dipole with a capacitive fingers feed for impedance matching that is highly robust against manufacturing errors. Upon deployment, the antennas exhibit a \u221210 dB-bandwidth >1.5 GHz and >110\u00b0 half-power beam width single lobe pattern suitable for beamforming.", "doi": "10.1109/aps/ursi47566.2021.9704302", "isbn": "978-1-7281-4670-6", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2021-12-04", "pages": "545-546" }, { "id": "authors:hbm88-hza38", "collection": "authors", "collection_id": "hbm88-hza38", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220121-11745000", "type": "book_section", "title": "A Compact, Low-Drive-Voltage Mach-Zehnder Modulator Using Serially-Coupled Rings", "book_title": "2021 IEEE 17th International Conference on Group IV Photonics (GFP)", "author": [ { "family_name": "Khachaturian", "given_name": "Aroutin", "orcid": "0000-0001-8304-3302", "clpid": "Khachaturian-Aroutin" }, { "family_name": "Porsandeh Khial", "given_name": "Parham", "orcid": "0000-0002-3242-8541", "clpid": "Porsandeh-Khial-Parham" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A novel, low-drive-voltage, and compact modulator using serially-coupled ring resonators in a Mach-Zehnder interferometer (MZI) linearly reduces the modulator's energy consumption as the number of rings in the chain increases. Such an MZI with three serially-coupled rings is invested for typical silicon photonics platforms.", "doi": "10.1109/gfp51802.2021.9673938", "isbn": "978-1-6654-2224-6", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2021-12", "pages": "1-2" }, { "id": "authors:cfedq-42j80", "collection": "authors", "collection_id": "cfedq-42j80", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20211104-153445242", "type": "article", "title": "A Framework for Array Shape Reconstruction Through Mutual Coupling", "author": [ { "family_name": "Fikes", "given_name": "Austin", "orcid": "0000-0003-4889-5782", "clpid": "Fikes-Austin" }, { "family_name": "Mizrahi", "given_name": "Oren S.", "orcid": "0000-0003-4271-8822", "clpid": "Mizrahi-Oren-S" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Flexible phased arrays potentially enable diverse applications not permitted by rigid systems; however, they introduce ambiguity in antenna element positions. If this position ambiguity can be overcome, flexible arrays can perform the full suite of array functions: beam steering, wavefront engineering, and beam focusing. Furthermore, shape reconstructions of arrays can be used for applications beyond beamforming. We propose a framework to reconstruct the shape of a flexible array that only uses mutual coupling measurements and does not require additional sensors or functionalities in the system. We discuss the approach, a two-step algorithm, which is highly modular and can be implemented in a variety of phased array systems. To demonstrate the accuracy of the approach, we present results from two passive 2.5-GHz phased array setups using dipole and patch antennas, as well as a 10-GHz (active) integrated circuit flexible phased array, and demonstrate the accuracy of the approach in this system. In all cases, the algorithm reconstructs the antenna shape accurately, with average position errors of approximately 6% of the wavelength. This article can serve as the beginning of the broad study of shape reconstruction algorithms and their applications.", "doi": "10.1109/tmtt.2021.3097729", "issn": "0018-9480", "publisher": "Institute of Electrical and Electronics Engineers", "publication": "IEEE Transactions on Microwave Theory and Techniques", "publication_date": "2021-10", "series_number": "10", "volume": "69", "issue": "10", "pages": "4422-4436" }, { "id": "authors:cd6sp-5ek98", "collection": "authors", "collection_id": "cd6sp-5ek98", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20211217-98205000", "type": "article", "title": "IQ Photonic Receiver for Coherent Imaging With a Scalable Aperture", "author": [ { "family_name": "Khachaturian", "given_name": "Aroutin", "orcid": "0000-0001-8304-3302", "clpid": "Khachaturian-Aroutin" }, { "family_name": "Fatemi", "given_name": "Reza", "orcid": "0000-0001-9081-2608", "clpid": "Fatemi-Reza" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Silicon photonics (SiP) integrated coherent image sensors offer higher sensitivity and improved range-resolution-product compared to direct detection image sensors such as CCD and CMOS devices. Previous generations of SiP coherent imagers suffer from relative optical phase fluctuations between the signal and reference paths, which results in random phase and amplitude fluctuations in the output signal. This limitation negatively impacts the SNR and signal acquisition times. Here, we present a coherent imager system that suppresses the optical carrier signal and removes non-idealities from the relative optical path using a photonic in-phase (I) and quadrature (Q) receiver via a 90\u00b0 hybrid detector. Furthermore, we incorporate row-column read-out and row-column addressing schemes to address the electro-optical interconnect density challenge. Our novel row-column read-out architecture for the sensor array requires only 2N interconnects for N\u00b2 sensors. An 8\u00d78 IQ sensor array is presented as a proof-of-concept demonstration with 1.2\u00d710\u207b\u2075 resolution over range accuracy. Free-space FMCW ranging with 250\u03bcm resolution at 1 m distance has been demonstrated using this sensor array.", "doi": "10.1109/ojsscs.2021.3113264", "issn": "2644-1349", "publisher": "Institute of Electrical and Electronics Engineers", "publication": "IEEE Open Journal of the Solid-State Circuits Society", "publication_date": "2021-09-17", "volume": "1", "pages": "263-270" }, { "id": "authors:6zjk5-1nj75", "collection": "authors", "collection_id": "6zjk5-1nj75", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20201215-141035798", "type": "article", "title": "Dynamic Focusing of Large Arrays for Wireless Power Transfer and Beyond", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-Behrooz" }, { "family_name": "Bohn", "given_name": "Florian", "orcid": "0000-0002-4619-378X", "clpid": "Bohn-Florian" }, { "family_name": "Gal-Katziri", "given_name": "Matan", "orcid": "0000-0001-9100-1188", "clpid": "Gal-Katziri-Matan" }, { "family_name": "Manohara", "given_name": "Mohith H.", "orcid": "0000-0003-1180-8470", "clpid": "Manohara-Mohith-H" } ], "abstract": "We present architectures, circuits, and algorithms for dynamic 3-D lensing and focusing of electromagnetic power in radiative near- and far-field regions by arrays that can be arbitrary and nonuniform. They can benefit applications such as wireless power transfer at a distance (WPT-AD), volumetric sensing and imaging, high-throughput communications, and optical phased arrays. Theoretical limits on system performance are calculated. An adaptive algorithm focuses the power at the receiver(s) without prior knowledge of its location(s). It uses orthogonal bases to change the phases of multiple elements simultaneously to enhance the dynamic range. One class of such 2-D orthogonal and pseudo-orthogonal masks is constructed using the Hadamard and pseudo-Hadamard matrices. Generation and recovery units (GU and RU) work collaboratively to focus energy quickly and reliably with no need for factory calibration. Orthogonality enables batch processing in high-latency and low-rate communication settings. Secondary vector-based calculations allow instantaneous refocusing at different locations using element-wise calculations. An emulator enables further evaluation of the system. We demonstrate modular WPT-AD GUs of up to 400 elements utilizing arrays of 65-nm CMOS ICs to focus power on RUs that convert the RF power to dc. Each RFIC synthesizes 16 independently phase-controlled RF outputs around 10 GHz from a common single low-frequency reference. Detailed measurements demonstrate the feasibility and effectiveness of RF lensing techniques presented in this article. More than 2 W of dc power can be recovered through a wireless transfer at distances greater than 1 m. The system can dynamically project power at various angles and at distances greater than 10 m. These developments are another step toward unified wireless power, sensing, and communication solutions in the future.", "doi": "10.1109/JSSC.2020.3036895", "issn": "0018-9200", "publisher": "IEEE", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2021-07", "series_number": "7", "volume": "56", "issue": "7", "pages": "2077-2101" }, { "id": "authors:kqdm1-3k663", "collection": "authors", "collection_id": "kqdm1-3k663", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210825-145535372", "type": "book_section", "title": "A 28 GHz Optically Synchronized CMOS Phased Array with an Integrated Photodetector", "book_title": "2021 IEEE Radio Frequency Integrated Circuits Symposium (RFIC)", "author": [ { "family_name": "Gal-Katziri", "given_name": "Matan", "orcid": "0000-0001-9100-1188", "clpid": "Gal-Katziri-Matan" }, { "family_name": "Ives", "given_name": "Craig", "clpid": "Ives-Craig-E" }, { "family_name": "Khakpour", "given_name": "Armina", "clpid": "Khakpour-Armina" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper presents a modular 28 GHz phased array. Each of its 2\u00d74-modules is driven by a CMOS RFIC, whose RF output is optically synchronized using a fully integrated silicon photodiode. The photocurrent is amplified using a tuned injection-locked TIA to serve as the reference for an on-chip synthesizer, which generates and distributes the RF signal to the PAs that drive the antennas. We demonstrate beam steering, data transmission, and synchronization of array modules up to 25m away from the clock source.", "doi": "10.1109/rfic51843.2021.9490452", "isbn": "978-1-6654-2549-0", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2021-06-07", "pages": "111-114" }, { "id": "authors:jqsjs-sgp50", "collection": "authors", "collection_id": "jqsjs-sgp50", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220105-101236400", "type": "book_section", "title": "Flexible Phased Array Shape Reconstruction", "book_title": "2021 IEEE MTT-S International Microwave Symposium (IMS)", "author": [ { "family_name": "Mizrahi", "given_name": "Oren S.", "orcid": "0000-0003-4271-8822", "clpid": "Mizrahi-Oren-S" }, { "family_name": "Fikes", "given_name": "Austin", "orcid": "0000-0003-4889-5782", "clpid": "Fikes-Austin" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Lightweight, flexible phased arrays enable new applications by dynamically changing shape during deployment and operation. However, these shape changes must be tracked and accounted for by changing the element excitation in order for the array to continue proper operation. We propose a framework for reconstructing the shape of a flexible phased array using only measurements of mutual coupling between the antennas in the array. The framework is demonstrated using a passive 2.5 GHz phased array and fixed to 8 different frames of known radii of convex and concave curvature. Our results show the ability to reconstruct shape to within \u2248 0.04\u03bb position error, even in cases where the phased array is bent dramatically, without any advanced knowledge or additional information. The framework is modular and can be easily adapted to other phased array systems with different antennas, frequencies, and physical constraints.", "doi": "10.1109/ims19712.2021.9574941", "isbn": "978-1-6654-0307-8", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2021-06-07", "pages": "31-33" }, { "id": "authors:6k6e0-prt13", "collection": "authors", "collection_id": "6k6e0-prt13", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210113-163505538", "type": "article", "title": "Programmable Active Mirror: A Scalable Decentralized Router", "author": [ { "family_name": "Fikes", "given_name": "Austin", "orcid": "0000-0003-4889-5782", "clpid": "Fikes-Austin" }, { "family_name": "Khial", "given_name": "Parham P.", "orcid": "0000-0002-3242-8541", "clpid": "Khial-Parham-P" }, { "family_name": "Nooshabadi", "given_name": "Samir", "clpid": "Nooshabadi-Samir" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This work proposes and demonstrates the scalable router array that eliminates the internal centralization of conventional arrays, unlocking scalability, and the potential for a system composed of spatially separated elements that do not share a common timing reference. Architectural variations are presented, and their specific tradeoffs are discussed. The general operation, steering capabilities, signal and noise considerations, and timing control advantages are evaluated through analysis, simulation, and measurements. An element-level CMOS radio frequency integrated circuit (RFIC) is developed and used to demonstrate a four-element 25 GHz prototype router. The RFIC's programmable true time delay (TTD) control is used to correct path-length-difference-induced intersymbol interference (ISI) and improve a rerouted 270-Mb/s 64-QAM constellation from a completely scrambled state to an EVM of 4% rms (\u221228 dB). The prototype scalable router's concurrent dual-beam capabilities are demonstrated by simultaneously steering two full power beams at 24.9 and 25 GHz in two different directions in a free-space electromagnetic setup.", "doi": "10.1109/tmtt.2020.3042516", "issn": "0018-9480", "publisher": "IEEE", "publication": "IEEE Transactions on Microwave Theory and Techniques", "publication_date": "2021-03", "series_number": "3", "volume": "69", "issue": "3", "pages": "1860-1874" }, { "id": "authors:fgyxk-ff673", "collection": "authors", "collection_id": "fgyxk-ff673", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210211-102546915", "type": "article", "title": "Subtractive photonics", "author": [ { "family_name": "Fatemi", "given_name": "Reza", "orcid": "0000-0001-9081-2608", "clpid": "Fatemi-Reza" }, { "family_name": "Ives", "given_name": "Craig", "clpid": "Ives-Craig-E" }, { "family_name": "Khachaturian", "given_name": "Aroutin", "orcid": "0000-0001-8304-3302", "clpid": "Khachaturian-Aroutin" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Realization of a multilayer photonic process, as well as co-integration of a large number of photonic and electronic components on a single substrate, presents many advantages over conventional solutions and opens a pathway for various novel architectures and applications. Despite the many potential advantages, realization of a complex multilayer photonic process compatible with low-cost CMOS platforms remains challenging. In this paper, a photonic platform is investigated that uses subtractively manufactured structures to fabricate such systems. These structures are created solely using simple post-processing methods, with no modification to the foundry process. This method uses the well-controlled metal layers of advanced integrated electronics as sacrificial layers to define dielectric shapes as optical components. Metal patterns are removed using an etching process, leaving behind a complex multilayer photonic system, while keeping the electronics'metal wiring intact. This approach can be applied to any integrated chip with well-defined metallization, including those produced in pure electronics processes, pure photonics processes, heterogeneously integrated processes, monolithic electronic-photonic processes, etc. This paper provides a proof-of-concept example of monolithic electronic-photonic integration in a 65\u2009nm bulk CMOS process and demonstrates proof-of-concept photonic structures. The fabrication results, characterization, and measurement data are presented.", "doi": "10.1364/oe.410139", "issn": "1094-4087", "publisher": "Optical Society of America", "publication": "Optics Express", "publication_date": "2021-01-18", "series_number": "2", "volume": "29", "issue": "2", "pages": "877-893" }, { "id": "authors:ecawf-37x45", "collection": "authors", "collection_id": "ecawf-37x45", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20201002-151459041", "type": "article", "title": "Breaking FOV-Aperture Trade-Off with Multi-Mode Nano-Photonic Antennas", "author": [ { "family_name": "Fatemi", "given_name": "Reza", "orcid": "0000-0001-9081-2608", "clpid": "Fatemi-R" }, { "family_name": "Khial", "given_name": "Parham P.", "orcid": "0000-0002-3242-8541", "clpid": "Khial-P-P" }, { "family_name": "Khachaturian", "given_name": "Aroutin", "orcid": "0000-0001-8304-3302", "clpid": "Khachaturian-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Nano-photonic antennas are one of the key components in integrated photonic transmitter and receiver systems. Conventionally, grating couplers, designed to couple into an optical fiber, suffering from limitations such as large footprint and small field-of-view (FOV) have been used as on-chip antennas. The challenge of the antenna design is more pronounced for the receiver systems, where both the collected power by the antenna and its FOV often need to be maximized. While some novel solutions have been demonstrated recently, identifying fundamental limits and trade-offs in nano-photonic antenna design is essential for devising compact antenna structures with improved performance. In this paper, the fundamental electromagnetic limits, as well as fabrication imposed constraints on improving antenna effective aperture and FOV are studied, and approximated performance upper limits are derived and quantified. By deviating from the conventional assumptions leading to these limits, high-performance multi-mode antenna structures with performance characteristics beyond the conventional perceived limits are demonstrated. Finally, the application of a pillar multi-mode antenna in a dense array is discussed, an antenna array with more than 95% collection efficiency and 170\u2218 FOV is demonstrated, and a coherent receiving system utilizing such an aperture is presented.", "doi": "10.1109/jstqe.2020.3026966", "issn": "1077-260X", "publisher": "IEEE", "publication": "IEEE Journal of Selected Topics in Quantum Electronics", "publication_date": "2021-01", "series_number": "1", "volume": "27", "issue": "1", "pages": "Art. No. 6100614" }, { "id": "authors:zt63z-d7141", "collection": "authors", "collection_id": "zt63z-d7141", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210205-093044804", "type": "book_section", "title": "Origami-Inspired Shape-Changing Phased Array", "book_title": "2020 50th European Microwave Conference (EuMC)", "author": [ { "family_name": "Williams", "given_name": "D. Elliott", "clpid": "Williams-D-Elliott" }, { "family_name": "Dorn", "given_name": "Charles", "orcid": "0000-0001-6516-2586", "clpid": "Dorn-Charles" }, { "family_name": "Pellegrino", "given_name": "Sergio", "orcid": "0000-0001-9373-3278", "clpid": "Pellegrino-S" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "In situ geometric reconfiguration of a phased array increases the diversity of radiation patterns that can be synthesized by the array. Such shape-changing phased arrays enable new applications by dynamically conforming their shapes to the geometry best suited for a given task. This work presents the design and demonstration of an origami-inspired shape-changing array built out of identical radiating tiles held in place by a mechanical backbone. The array is capable of shifting into planar, spherical, and cylindrical configurations. The benefits of such an array are analyzed by comparing the properties of different geometries and verified with measurements of the first origami-inspired shape-changing phased array.", "doi": "10.23919/eumc48046.2021.9338189", "isbn": "9782874870590", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2021-01", "pages": "344-347" }, { "id": "authors:2y68k-vgh08", "collection": "authors", "collection_id": "2y68k-vgh08", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20201015-152732825", "type": "book_section", "title": "Scalable, Deployable, Flexible Phased Array Sheets", "book_title": "2020 IEEE/MTT-S International Microwave Symposium (IMS)", "author": [ { "family_name": "Gal-Katziri", "given_name": "Matan", "orcid": "0000-0001-9100-1188", "clpid": "Gal-Katziri-M" }, { "family_name": "Fikes", "given_name": "Austin", "clpid": "Fikes-A-C" }, { "family_name": "Bohn", "given_name": "Florian", "clpid": "Bohn-F" }, { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Hashemi", "given_name": "M. Reza", "orcid": "0000-0002-3312-4005", "clpid": "Hashemi-M-Reza" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Large aperture flexible and deployable phased arrays will enable active RF fabric and deployable array structures for terrestrial and space applications. The flexible phased array design paradigm is enabled by small, multi-function radio frequency integrated circuits and low mass radiators, which avoid conventional dielectric materials. This paper presents a 256 element, 30 cm x 30 cm flexible phased array, operating at 10 GHz and focusing 0.8 W at 2 m distance. A novel beam-focusing algorithm is used to demonstrate 2-D beam-steering and deformation correction capabilities of the flexible phased array.", "doi": "10.1109/ims30576.2020.9224066", "isbn": "9781728168159", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2020-08", "pages": "1085-1088" }, { "id": "authors:6sjsf-rw152", "collection": "authors", "collection_id": "6sjsf-rw152", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200528-104303291", "type": "article", "title": "Dynamically Programmable Magnetic Fields for Controlled Movement of Cells Loaded with Iron Oxide Nanoparticles", "author": [ { "family_name": "Pai", "given_name": "Alex", "clpid": "Pai-Alex" }, { "family_name": "Cao", "given_name": "Pengpeng", "clpid": "Cao-Pengpeng" }, { "family_name": "White", "given_name": "Ethan E.", "clpid": "White-E-E" }, { "family_name": "Hong", "given_name": "Brian", "orcid": "0000-0001-8099-0312", "clpid": "Hong-Brian" }, { "family_name": "Pailevanian", "given_name": "Torkom", "clpid": "Pailevanian-T" }, { "family_name": "Wang", "given_name": "Michelle", "clpid": "Wang-Michelle" }, { "family_name": "Badie", "given_name": "Behnam", "clpid": "Badie-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Berlin", "given_name": "Jacob M.", "orcid": "0000-0001-7498-766X", "clpid": "Berlin-J-M" } ], "abstract": "Cell-based therapies are becoming increasingly prominent in numerous medical contexts, particularly in regenerative medicine and the treatment of cancer. However, since the efficacy of the therapy is largely dependent on the concentration of therapeutic cells at the treatment area, a major challenge associated with cell-based therapies is the ability to move and localize therapeutic cells within the body. In this article, a technique based on dynamically programmable magnetic fields is successfully demonstrated to noninvasively aggregate therapeutic cells at a desired location. Various types of therapeutically relevant cells (neural stem cells, monocytes/macrophages, and chimeric antigen receptor T cells) are loaded with iron oxide nanoparticles and then focused at a particular site using externally controlled electromagnets. These experimental results serve as a readily scalable prototype for designing an apparatus that patients can wear to focus therapeutic cells at the anatomical sites needed for treatment.", "doi": "10.1021/acsabm.0c00226", "issn": "2576-6422", "publisher": "American Chemical Society", "publication": "ACS Applied Bio Materials", "publication_date": "2020-07-20", "series_number": "7", "volume": "3", "issue": "7", "pages": "4139-4147" }, { "id": "authors:dtden-pmq53", "collection": "authors", "collection_id": "dtden-pmq53", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200402-141913396", "type": "article", "title": "An mm-Wave CMOS I-Q Subharmonic Resistive Mixer for Wideband Zero-IF Receivers", "author": [ { "family_name": "Parveg", "given_name": "Dristy", "orcid": "0000-0002-9166-8764", "clpid": "Parveg-D" }, { "family_name": "Varonen", "given_name": "Mikko", "orcid": "0000-0002-6515-5092", "clpid": "Varonen-M" }, { "family_name": "Safaripour", "given_name": "Amirreza", "orcid": "0000-0001-9758-6156", "clpid": "Safaripour-A" }, { "family_name": "Kangaslahti", "given_name": "Pekka", "clpid": "Kangaslahti-P" }, { "family_name": "Kantanen", "given_name": "Mikko", "clpid": "Kantanen-M" }, { "family_name": "Tikka", "given_name": "Tero", "clpid": "Tikka-T" }, { "family_name": "Gaier", "given_name": "Todd", "clpid": "Gaier-T" }, { "family_name": "Halonen", "given_name": "Kari A. I.", "clpid": "Halonen-K-A-I" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "In this letter, we propose a novel wideband subharmonically pumped fully differential I\u2013Q resistive mixer architecture, which eliminates the necessity for on-chip dc-blocking capacitors to integrate IF amplifiers. The proposed differential subharmonic mixer topology is verified by presenting a CMOS millimeter-wave monolithic integrated circuit (MMIC), which includes the mixer and two on-chip differential IF amplifiers at the mixer's I- and Q-channels. The 3-dB IF frequency bandwidth is measured from 0.01 to 5 GHz with a peak conversion gain (CG) of \u22122 dB and an image rejection ratio (IRR) of more than 25 dB over the IF frequency range. The proposed mixer covers the input signal (RF) frequency from 170 to 185 GHz. The mixer has also been tested with an on-chip voltage-controlled oscillator (VCO) and shows \u22124.7-dB CG with a 3-dB IF bandwidth from 0.01 to 4.5 GHz.", "doi": "10.1109/lmwc.2020.2980973", "issn": "1531-1309", "publisher": "IEEE", "publication": "IEEE Microwave and Wireless Components Letters", "publication_date": "2020-05", "series_number": "5", "volume": "30", "issue": "5", "pages": "520-523" }, { "id": "authors:psq03-x5843", "collection": "authors", "collection_id": "psq03-x5843", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200430-152742107", "type": "book_section", "title": "A Fully Integrated, Dual Channel, Flip Chip Packaged 113 GHz Transceiver in 28nm CMOS supporting an 80 Gb/s Wireless Link", "book_title": "2020 IEEE Custom Integrated Circuits Conference (CICC)", "author": [ { "family_name": "Townley", "given_name": "Andrew", "clpid": "Townley-A" }, { "family_name": "Baniasadi", "given_name": "Nima", "clpid": "Baniasadi-N" }, { "family_name": "Krishnamurthy", "given_name": "Sashank", "clpid": "Krishnamurthy-Sashank" }, { "family_name": "Sideris", "given_name": "Constantine", "orcid": "0000-0002-3042-4889", "clpid": "Sideris-C" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Alon", "given_name": "Elad", "clpid": "Alon-E" }, { "family_name": "Niknejad", "given_name": "Ali", "clpid": "Niknejad-A" } ], "abstract": "In order to meet the demand for increasingly higher data rate wireless links, broad-bandwidth transceivers that support high-spectral-efficiency modulation schemes are required. In this paper, a mm-wave transceiver IC operating at 113GHz is demonstrated, achieving a single-channel data rate of 80Gb/s. The transceiver achieves a high level of integration, including LO generation circuitry, a bits-to-RF TX DAC, and two transceiver channels for polarization diversity. The chip is flip-chip packaged onto a PCB with two orthogonally polarized antennas.", "doi": "10.1109/cicc48029.2020.9075890", "isbn": "9781728160313", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2020-03", "pages": "1-4" }, { "id": "authors:9tjrk-xgy56", "collection": "authors", "collection_id": "9tjrk-xgy56", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200212-111715644", "type": "article", "title": "A Silicon Photonics Computational Lensless Active-Flat-Optics Imaging System", "author": [ { "family_name": "White", "given_name": "Alexander", "orcid": "0000-0002-5387-310X", "clpid": "White-A-D" }, { "family_name": "Khial", "given_name": "Parham", "orcid": "0000-0002-3242-8541", "clpid": "Khial-P-P" }, { "family_name": "Salehi", "given_name": "Fariborz", "clpid": "Salehi-F" }, { "family_name": "Hassibi", "given_name": "Babak", "orcid": "0000-0002-1375-5838", "clpid": "Hassibi-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "The need for lightweight, miniature imaging systems is becoming increasingly prevalent in light of the development of wearable electronics, IoT devices, and drones. Computational imaging enables new types of imaging systems that replace standard optical components like lenses with cleverly designed computational processes. Traditionally, many of these types of systems use conventional complementary metal oxide semiconductor (CMOS) or charge coupled device (CCD) sensors for data collection. While this allows for rapid development of large-scale systems, the lack of system-sensor co-design limits the compactness and performance. Here we propose integrated photonics as a candidate platform for the implementation of such co-integrated systems. Using grating couplers and co-designed computational processing in lieu of a lens, we demonstrate the use of silicon photonics as a viable platform for computational imaging with a prototype lensless imaging device. The proof-of-concept device has 20 sensors and a 45-degree field of view, and its optics and sensors are contained within a 2,000 \u03bcm \u00d7 200 \u03bcm \u00d7 20 \u03bcm volume.", "doi": "10.1038/s41598-020-58027-1", "pmcid": "PMC6997425", "issn": "2045-2322", "publisher": "Nature Publishing Group", "publication": "Scientific Reports", "publication_date": "2020-02-03", "volume": "10", "pages": "Art. No. 1689" }, { "id": "authors:kdfym-b3b02", "collection": "authors", "collection_id": "kdfym-b3b02", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190926-144327410", "type": "article", "title": "Computational aberration correction of VIS-NIR multispectral imaging microscopy based on Fourier ptychography", "author": [ { "family_name": "Shen", "given_name": "Cheng", "orcid": "0000-0001-7136-4715", "clpid": "Shen-Cheng" }, { "family_name": "Chan", "given_name": "Antony Chi Shing", "clpid": "Chan-Antony-Chi-Shing" }, { "family_name": "Chung", "given_name": "Jaebum", "orcid": "0000-0003-3932-8428", "clpid": "Chung-Jaebum" }, { "family_name": "Williams", "given_name": "D. Elliott", "clpid": "Williams-D-E" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Yang", "given_name": "Changhuei", "orcid": "0000-0001-8791-0354", "clpid": "Yang-Changhuei" } ], "abstract": "Due to the chromatic dispersion properties inherent in all optical materials, even the best-designed multispectral objective will exhibit residual chromatic aberration. Here, we demonstrate a multispectral microscope with a computational scheme based on the Fourier ptychographic microscopy (FPM) to correct these effects in order to render undistorted, in-focus images. The microscope consists of 4 spectral channels ranging from 405 nm to 1552 nm. After the computational aberration correction, it can achieve isotropic resolution enhancement as verified with the Siemens star sample. We image a flip-chip to show the promise of our system to conduct fault detection on silicon chips. This computational approach provides a cost-efficient strategy for high quality multispectral imaging over a broad spectral range.", "doi": "10.1364/oe.27.024923", "issn": "1094-4087", "publisher": "Optical Society of America", "publication": "Optics Express", "publication_date": "2019-09-02", "series_number": "18", "volume": "27", "issue": "18", "pages": "24923-24937" }, { "id": "authors:b0yg2-18986", "collection": "authors", "collection_id": "b0yg2-18986", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190814-152418722", "type": "article", "title": "Proximal-Field Sensing: In Situ Prediction of Far-Field Radiation for Integrated Radiators", "author": [ { "family_name": "Safaripour", "given_name": "Amirreza", "orcid": "0000-0001-9758-6156", "clpid": "Safaripour-A" }, { "family_name": "Asghari", "given_name": "Bahar", "clpid": "Asghari-B" }, { "family_name": "Hashemi", "given_name": "Mohammed Reza M.", "orcid": "0000-0002-8908-0048", "clpid": "Hashemi-M-R-M" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Proximal-field sensing is introduced as an integrated sensing scheme for the in situ characterization of far-field radiation properties of integrated radiators, and the proximal-field radiation sensors (PFRSs) are proposed as the tools to enable this capability. These sensors are integrated on the same dielectric substrate as the transmitting antennas and extract the existing information in the excited substrate modes and use it to predict the far-field radiation properties in real time based on in situ field measurements in the close proximity of the transmitting antennas, without any need to use additional test equipment, remove the antenna from its operating environment, or interrupt its operation in a wireless system. The functionality of this sensing scheme is verified on both PCB and IC platforms through the implementation of two proof-of-concept prototypes, and different aspects of the electromagnetic and electronic design of the PFRS integration with integrated radiators are investigated.", "doi": "10.1109/tmtt.2019.2929154", "issn": "0018-9480", "publisher": "IEEE", "publication": "IEEE Transactions on Microwave Theory and Techniques", "publication_date": "2019-09", "series_number": "9", "volume": "67", "issue": "9", "pages": "3743-3756" }, { "id": "authors:beeyt-tfj40", "collection": "authors", "collection_id": "beeyt-tfj40", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190709-133258992", "type": "article", "title": "A General Theory of Injection Locking and Pulling in Electrical Oscillators--Part I: Time-Synchronous Modeling and Injection Waveform Design", "author": [ { "family_name": "Hong", "given_name": "Brian", "orcid": "0000-0001-8099-0312", "clpid": "Hong-Brian" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A general model of electrical oscillators under the influence of a periodic injection is presented. Stemming solely from the autonomy and periodic time variance inherent in all oscillators, the model's underlying approach makes no assumptions about the topology of the oscillator or the shape of the injection waveform. A single first-order differential equation is shown to be capable of predicting a number of important properties, including the lock range, the relative phase of an injection-locked oscillator, and mode stability. The framework also reveals how the injection waveform can be designed to optimize the lock range. A diverse collection of simulations and measurements, performed on various types of oscillators, serve to verify the proposed theory.", "doi": "10.1109/jssc.2019.2908753", "issn": "0018-9200", "publisher": "IEEE", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2019-08", "series_number": "8", "volume": "54", "issue": "8", "pages": "2109-2121" }, { "id": "authors:5gka5-51e69", "collection": "authors", "collection_id": "5gka5-51e69", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190711-133035819", "type": "article", "title": "A General Theory of Injection Locking and Pulling in Electrical Oscillators--Part II: Amplitude Modulation in LC Oscillators, Transient Behavior, and Frequency Division", "author": [ { "family_name": "Hong", "given_name": "Brian", "orcid": "0000-0001-8099-0312", "clpid": "Hong-Brian" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A number of specialized topics within the theory of injection locking and pulling are addressed. The material builds on our impulse sensitivity function (ISF)-based, time-synchronous model of electrical oscillators under the influence of a periodic injection. First, we show how the accuracy of this model for LC oscillators under large injection is greatly enhanced by accounting for the injection's effect on the oscillation amplitude. In doing so, we capture the asymmetry of the lock range as well as the distinct behaviors exhibited by different LC oscillator topologies. Existing LC oscillator injection locking and pulling theories in the literature are subsumed as special cases. Next, a transient analysis of the dynamics of injection pulling is carried out, both within and outside of the lock range. Finally, we show how our existing framework naturally accommodates locking onto superharmonic and subharmonic injections, leading to several design considerations for injection-locked frequency dividers (ILFDs) and the implementation of a low-power dual-modulus prescaler from an injection-locked ring oscillator. Our theoretical conclusions are supported by simulations and experimental data from a variety of LC, ring, and relaxation oscillators.", "doi": "10.1109/jssc.2019.2908763", "issn": "0018-9200", "publisher": "IEEE", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2019-08", "series_number": "8", "volume": "54", "issue": "8", "pages": "2122-2139" }, { "id": "authors:z3p1g-rzw92", "collection": "authors", "collection_id": "z3p1g-rzw92", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190718-133623700", "type": "article", "title": "Analysis and Design of Coupled Inductive Bridges for Magnetic Sensing Applications", "author": [ { "family_name": "Gal-Katziri", "given_name": "Matan", "orcid": "0000-0001-9100-1188", "clpid": "Gal-Katziri-M" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper presents the analysis and design of a novel magnetic sensor. We study the underlying physics of inductance shift sensors as a special case of the broader family of magnetic energy deviation sensors. The result is a quantitative definition of performance metrics with all assumptions and approximations explicitly stated. This analysis is then used to design a modified ac Wheatstone bridge that uses two inductor-pairs in a cross-coupled configuration, to half its size and double its transducer gain while maintaining a fully differential structure with a matched frequency response. A proof-of-concept sensor was fabricated with peripheral circuitry in a 65-nm bulk CMOS process to operate between 770 and 1450 MHz with an effective sensing area of 200 \u00b5m x 200 \u00b5m. The new bridge sensor is fully characterized at a frequency of 770 MHz and demonstrates a reliable and continuous detection of 4.5-\u00b5m iron-oxide magnetic beads over time periods longer than 30 min, appreciably longer than previously reported works.", "doi": "10.1109/jssc.2019.2907196", "issn": "0018-9200", "publisher": "IEEE", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2019-07", "series_number": "7", "volume": "54", "issue": "7", "pages": "1883-1894" }, { "id": "authors:27wy6-xp082", "collection": "authors", "collection_id": "27wy6-xp082", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190801-154731156", "type": "book_section", "title": "Flexible, Conformal Phased Arrays with Dynamic Array Shape Self-Calibration", "book_title": "2019 IEEE MTT-S International Microwave Symposium (IMS)", "author": [ { "family_name": "Fikes", "given_name": "Austin C.", "clpid": "Fikes-A-C" }, { "family_name": "Safaripour", "given_name": "Amirreza", "orcid": "0000-0001-9758-6156", "clpid": "Safaripour-A" }, { "family_name": "Bohn", "given_name": "Florian", "clpid": "Bohn-F" }, { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Flexible and conformal phased arrays enable a broad range of novel applications. One of the major challenges for such systems is that they experience a change in their behavior when bent or deformed. A self-calibrating flexible phased array can overcome this by estimating the relative position change of its elements as they undergo local deformations. In this work, we demonstrate a dynamically flexible and conformal 8-element phased array based on a custom CMOS transceiver unit. Beam-steering is demonstrated with the flexible array flat and with the array conformed to convex and concave bend radii of \u00b1120 mm. In addition, we propose and test a shape calibration method that uses only the coupling between elements, using the flexible phase array.", "isbn": "978-1-7281-1309-8", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2019-06", "pages": "1458-1461" }, { "id": "authors:c7qwz-bzv53", "collection": "authors", "collection_id": "c7qwz-bzv53", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190712-092832892", "type": "book_section", "title": "A Photodetector-Driven Coherent RF Array with Wide Tuning Range", "book_title": "CLEO: Science and Innovations 2019", "author": [ { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Ives", "given_name": "Craig", "clpid": "Ives-C-E" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A sixteen-element coherent array of wideband spiral antennas driven by photodetectors is presented. The array radiates between 21 and 65 GHz, with \u221245 dBm of coupled power at 42 GHz.", "doi": "10.1364/cleo_si.2019.sf2n.6", "isbn": "978-1-943580-57-6", "publisher": "Optical Society of America", "place_of_publication": "Washington, DC", "publication_date": "2019-05", "pages": "Art. No. SF2N.6" }, { "id": "authors:8m3a5-09j94", "collection": "authors", "collection_id": "8m3a5-09j94", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190712-094214650", "type": "book_section", "title": "A Wideband On-Chip Radiator Driven by a Traveling-Wave Photodetector", "book_title": "CLEO: Science and Innovations 2019", "author": [ { "family_name": "Ives", "given_name": "Craig", "clpid": "Ives-C-E" }, { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "An integrated broadband Vivaldi antenna driven by an on-chip traveling-wave photodetector is reported. The silicon photonic chip radiates between 21 and 67 GHz with\u221265 dBm coupled power at 44 GHz.", "doi": "10.1364/cleo_si.2019.sth3h.7", "isbn": "978-1-943580-57-6", "publisher": "Optical Society of America", "place_of_publication": "Washington, DC", "publication_date": "2019-05", "pages": "Art. No. STh3H.7" }, { "id": "authors:aprqe-vd583", "collection": "authors", "collection_id": "aprqe-vd583", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190416-120325923", "type": "article", "title": "A flexible phased array system with low areal mass density", "author": [ { "family_name": "Hashemi", "given_name": "Mohammed Reza M.", "orcid": "0000-0002-8908-0048", "clpid": "Hashemi-M-R-M" }, { "family_name": "Fikes", "given_name": "Austin C.", "clpid": "Fikes-A-C" }, { "family_name": "Gal-Katziri", "given_name": "Matan", "orcid": "0000-0001-9100-1188", "clpid": "Gal-Katziri-M" }, { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Bohn", "given_name": "Florian", "clpid": "Bohn-F" }, { "family_name": "Safaripour", "given_name": "Amirreza", "orcid": "0000-0001-9758-6156", "clpid": "Safaripour-A" }, { "family_name": "Kelzenberg", "given_name": "Michael D.", "orcid": "0000-0002-6249-2827", "clpid": "Kelzenberg-M-D" }, { "family_name": "Warmann", "given_name": "Emily L.", "clpid": "Warmann-E-L" }, { "family_name": "Espinet", "given_name": "Pilar", "orcid": "0000-0002-7656-0077", "clpid": "Espinet-Gonz\u00e1lez-P" }, { "family_name": "Vaidya", "given_name": "Nina", "clpid": "Vaidya-N" }, { "family_name": "Gdoutos", "given_name": "Eleftherios E.", "clpid": "Gdoutos-E-E" }, { "family_name": "Leclerc", "given_name": "Christophe", "clpid": "Leclerc-C" }, { "family_name": "Royer", "given_name": "Fabien", "clpid": "Royer-F" }, { "family_name": "Pellegrino", "given_name": "Sergio", "orcid": "0000-0001-9373-3278", "clpid": "Pellegrino-S" }, { "family_name": "Atwater", "given_name": "Harry A.", "orcid": "0000-0001-9435-0201", "clpid": "Atwater-H-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Phased arrays are multiple antenna systems capable of forming and steering beams electronically using constructive and destructive interference between sources. They are employed extensively in radar and communication systems but are typically rigid, bulky and heavy, which limits their use in compact or portable devices and systems. Here, we report a scalable phased array system that is both lightweight and flexible. The array architecture consists of a self-monitoring complementary metal\u2013oxide\u2013semiconductor-based integrated circuit, which is responsible for generating multiple independent phase- and amplitude-controlled signal channels, combined with flexible and collapsible radiating structures. The modular platform, which can be collapsed, rolled and folded, is capable of operating standalone or as a subarray in a larger-scale flexible phased array system. To illustrate the capabilities of the approach, we created a 4\u2009\u00d7\u20094 flexible phased array tile operating at 9.4\u201310.4\u2009GHz, with a low areal mass density of 0.1\u2009g\u2009cm^(\u22122). We also created a flexible phased array prototype that is powered by photovoltaic cells and intended for use in a wireless space-based solar power transfer array.", "doi": "10.1038/s41928-019-0247-9", "issn": "2520-1131", "publisher": "Nature Publishing Group", "publication": "Nature Electronics", "publication_date": "2019-05", "series_number": "5", "volume": "2", "issue": "5", "pages": "195-205" }, { "id": "authors:tjhsy-mxr73", "collection": "authors", "collection_id": "tjhsy-mxr73", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190228-152237706", "type": "article", "title": "A Nonuniform Sparse 2-D Large-FOV Optical Phased Array With a Low-Power PWM Drive", "author": [ { "family_name": "Fatemi", "given_name": "Reza", "orcid": "0000-0001-9081-2608", "clpid": "Fatemi-R" }, { "family_name": "Khachaturian", "given_name": "Aroutin", "orcid": "0000-0001-8304-3302", "clpid": "Khachaturian-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Integrated optical phased arrays (OPAs) capable of adaptive beamforming and beam steering enable a wide range of applications. For many of these applications, a large scale 2-D OPA with full phase control for each radiating element is essential to achieve a functional low-cost solution. However, the scalability of such OPAs has been hampered by the optical feed distribution difficulties in a planar photonics process, as well as the high power consumption associated with having a large number of phase control units. In this paper, we present a two-chip solution low-power scalable OPA with a nonuniform sparse aperture, providing radiation pattern adjustment and feed distribution feasibility in a CMOS compatible silicon photonics process. The demonstrated OPA with a 128-element aperture achieves the highest reported grating-lobe-free field-of-view (FOV)-to-beamwidth ratio of 16\u00b0/0.8\u00b0, which is equivalent to a 484-element uniform array. This translates to at least 400 resolvable spots, 30 times more than the state-of-the-art 2-D OPAs. Moreover, by utilizing compact phase shifters in a row\u2013column power delivery grid, we reduce the number of required drivers from 144 to 37. A high-swing pulsewidth modulation (PWM) driving circuit featuring breakdown voltage multipliers and soft turn-on activation significantly reduces the power consumption of the system. The electronic driver chip and the integrated photonic chip are fabricated on a 65-nm CMOS process and a thick silicon-on-insulator (SOI) silicon photonics process, occupying 1.7 mm^2 and 2.08 mm^2 of active area, respectively.", "doi": "10.1109/jssc.2019.2896767", "issn": "0018-9200", "publisher": "IEEE", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2019-05", "series_number": "5", "volume": "54", "issue": "5", "pages": "1200-1215" }, { "id": "authors:92egn-2s343", "collection": "authors", "collection_id": "92egn-2s343", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190710-154813563", "type": "book_section", "title": "A Chip-Scale Nanophotonic Optical Gyroscope", "book_title": "2019 IEEE International Symposium on Inertial Sensors and Systems (INERTIAL)", "author": [ { "family_name": "Khial", "given_name": "Parham P.", "orcid": "0000-0002-3242-8541", "clpid": "Khial-P-P" }, { "family_name": "White", "given_name": "Alexander D.", "orcid": "0000-0002-5387-310X", "clpid": "White-A-D" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper presents the first demonstration of a nanophotonic optical gyroscope (NOG) on a silicon-photonic platform. Reciprocal sensitivity enhancement is introduced as an effective method to overcome the limitations of NOGs.", "doi": "10.1109/ISISS.2019.8739715", "isbn": "978-1-5386-7828-2", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2019-04", "pages": "1-3" }, { "id": "authors:m45qn-23c76", "collection": "authors", "collection_id": "m45qn-23c76", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190522-154638477", "type": "book_section", "title": "Extending the wavelength range of multi-spectral microscope systems with Fourier ptychography", "book_title": "Label-free Biomedical Imaging and Sensing (LBIS) 2019", "author": [ { "family_name": "Chan", "given_name": "Antony Chi Shing", "clpid": "Chan-Antony-Chi-Shing" }, { "family_name": "Shen", "given_name": "Cheng", "orcid": "0000-0001-7136-4715", "clpid": "Shen-Cheng" }, { "family_name": "Williams", "given_name": "Elliot", "clpid": "Williams-E" }, { "family_name": "Lyu", "given_name": "Xiaoyu", "clpid": "Lyu-Xiaoyu" }, { "family_name": "Lu", "given_name": "Hangwen", "clpid": "Lu-Hangwen" }, { "family_name": "Ives", "given_name": "Craig", "clpid": "Ives-C-E" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Yang", "given_name": "Changhuei", "orcid": "0000-0001-8791-0354", "clpid": "Yang-Changhuei" } ], "contributor": [ { "family_name": "Shaked", "given_name": "Natan T.", "clpid": "Shaked-N-T" }, { "family_name": "Hayden", "given_name": "Oliver", "clpid": "Hayden-O" } ], "abstract": "Due to the chromatic dispersion properties inherent in all optical materials, even the best designed multi-spectral objective will exhibit residual chromatic aberration effect. Here we show that the aberration correction ability of Fourier Ptychographic Microscopy (FPM) is well matched and well suited for post-image acquisition correction of these effects to render in-focus images. We show that an objective with significant spectral focal shift (up to 0.02 \u03bcm/nm) and spectral field curvature (up to 0.05 \u03bcm/nm drift at off-axis position of 800\u03bcm) can be computationally corrected to render images with effectively null spectral defocus and field curvature. This approach of combining optical objective design and computational microscopy provides a good strategy for high quality multi-spectral imaging over a broad spectral range, and eliminating the need for mechanical actuation solutions.", "doi": "10.1117/12.2510875", "isbn": "9781510624221", "publisher": "Society of Photo-optical Instrumentation Engineers (SPIE)", "place_of_publication": "Bellingham, WA", "publication_date": "2019-03-25", "pages": "Art. No. 108902O" }, { "id": "authors:6ajep-t6t43", "collection": "authors", "collection_id": "6ajep-t6t43", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190102-155139163", "type": "article", "title": "A Phasor-Based Analysis of Sinusoidal Injection Locking in LC and Ring Oscillators", "author": [ { "family_name": "Hong", "given_name": "Brian", "orcid": "0000-0001-8099-0312", "clpid": "Hong-Brian" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A new perspective into the locking behavior of LC and ring oscillators is presented. By decomposing a sinusoidal injection current into in-phase and quadrature-phase components, exact expressions for the amplitude and phase of an injection-locked LC oscillator which hold for any injection strength and frequency are derived and confirmed by simulation. The analysis, which can be naturally extended to an arbitrary LC resonator topology, leads to a rigorous understanding of the fundamental physics underlying the locking phenomenon. Furthermore, an investigation of the different necessary and sufficient conditions for injection locking to occur is carried out, leading to a more precise notion of the lock range. The ring oscillator is also analyzed in an analogous fashion, resulting in simple yet accurate closed-form expressions for the fractional lock range in the small-injection and long-ring regimes; the expressions are validated by simulations of single-ended inverter-based ring oscillators in 65-nm CMOS. The mathematics behind how the injection modifies the phase delay contributed by each stage in the ring is discussed. A corollary that generalizes the small-injection lock range to any feedback-based oscillator topology is established. Conceptual and analytical connections to the existing literature are reviewed.", "doi": "10.1109/tcsi.2018.2860045", "issn": "1549-8328", "publisher": "IEEE", "publication": "IEEE Transactions on Circuits and Systems I: Regular Papers", "publication_date": "2019-01", "series_number": "1", "volume": "66", "issue": "1", "pages": "355-368" }, { "id": "authors:1qvfa-4vr18", "collection": "authors", "collection_id": "1qvfa-4vr18", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181205-145145663", "type": "article", "title": "High sensitivity active flat optics optical phased array receiver with a two-dimensional aperture", "author": [ { "family_name": "Fatemi", "given_name": "Reza", "orcid": "0000-0001-9081-2608", "clpid": "Fatemi-R" }, { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Khachaturian", "given_name": "Aroutin", "orcid": "0000-0001-8304-3302", "clpid": "Khachaturian-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Optical phased arrays (OPAs) on integrated photonic platforms provide a low-cost chip-scale solution for many applications. Despite the numerous demonstrations of OPA transmitters, the realization of a functional OPA receiver presents a challenge due to the low received signal level in the presence of noise and interference that necessitates high sensitivity of the receiver. In this paper, an integrated receiver system is presented that is capable of on-chip adaptive manipulation and processing of the captured waveform. The receiver includes an optoelectronic mixer that down-converts optical signals to radio frequencies while maintaining their phase and amplitude information. The optoelectronic mixer also provides conversion gain that enhances the system sensitivity and its robustness to noise and interference. Using this system, the first OPA receiver with a two-dimensional aperture of 8-by-8 receiving elements is demonstrated which can selectively receive light from 64 different angles. The OPA receiver can form reception beams with a beamwidth of 0.75\u00b0 over an 8\u00b0 grating-lobe-free field of view.", "doi": "10.1364/oe.26.029983", "issn": "1094-4087", "publisher": "Optical Society of America", "publication": "Optics Express", "publication_date": "2018-11-12", "series_number": "23", "volume": "26", "issue": "23", "pages": "29983-29999" }, { "id": "authors:y6sdp-58y27", "collection": "authors", "collection_id": "y6sdp-58y27", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181023-151906461", "type": "article", "title": "Design and Implementation of Reference-Free Drift-Cancelling CMOS Magnetic Sensors for Biosensing Applications", "author": [ { "family_name": "Sideris", "given_name": "Constantine", "orcid": "0000-0002-3042-4889", "clpid": "Sideris-C" }, { "family_name": "Khial", "given_name": "Parham P.", "orcid": "0000-0002-3242-8541", "clpid": "Khial-P-P" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Magnetic imagers, which utilize magnetic nanoparticles as labels to realize biodetection assays, hold significant promise for deployment at the point-of-use. Resonance-shift-based sensors can be realized in standard CMOS processes without post-process modifications and offer great sensitivity at low price tags. Unfortunately, CMOS resonant-shift magnetic sensors suffer significant degradation in SNR and long-term stability due to low on-chip inductor quality factors and significant noise introduced from active devices and thermal variations. This makes standard resonant-shift-based imagers undesirable for use in low-signal biodetection assays. Furthermore, and most importantly, the significant long-term drift due to slow-varying noise sources and temperature changes makes these sensors inadequate for bioexperiments which may take timescales on the order of hours to reach completion. In this paper, we propose a transformer-based approach which enables sub-parts-per-million (PPM) signal detection without the need for any thermal compensation. The approach is self-referencing, leading to significant savings in chip area by removing the need for replica reference cells. We analyze the performance of the transformer-based circuit compared to the original second-order system and demonstrate its superiority for rejecting system noise. A proof-of-concept design of a fully integrated 2\u00d72 CMOS transformer-based magnetic sensor array is presented which achieves reference-free, sub-PPM detection of magnetic signals. The system can be powered and operated completely from a laptop USB interface and each sensing cell can consume less than 3 mW of DC power. Finally, we show the results of an initial DNA biodetection experiment which confirms the capability of the sensor to be used for realistic bioassays.", "doi": "10.1109/JSSC.2018.2865480", "issn": "0018-9200", "publisher": "IEEE", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2018-11", "series_number": "11", "volume": "53", "issue": "11", "pages": "3065-3075" }, { "id": "authors:npqpe-y4a45", "collection": "authors", "collection_id": "npqpe-y4a45", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190107-110253682", "type": "book_section", "title": "A Sub-Picosecond Hybrid DLL for Large-Scale Phased Array Synchronization", "book_title": "2018 IEEE Asian Solid-State Circuits Conference (A-SSCC)", "author": [ { "family_name": "Gal-Katziri", "given_name": "Matan", "orcid": "0000-0001-9100-1188", "clpid": "Gal-Katziri-M" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A large-scale timing synchronization scheme for scalable phased arrays is presented. This approach utilizes a DLL co-designed with a subsequent 2.5GHz PLL. The DLL employs a low noise, fine/coarse delay tuning to reduce the in-band rms jitter to 323fs, an order of magnitude improvement over previous works at similar frequencies. The DLL was fabricated in a 65nm bulk CMOS process and was characterized from 27MHz to 270MHz. It consumes up to 3.3mW from a 1V power supply and has a small footprint of 0.036mm^2.", "doi": "10.1109/ASSCC.2018.8579340", "isbn": "978-1-5386-6413-1", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2018-11", "pages": "231-234" }, { "id": "authors:k0gn4-zjp51", "collection": "authors", "collection_id": "k0gn4-zjp51", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180807-125405326", "type": "article", "title": "Nanophotonic optical gyroscope with reciprocal sensitivity enhancement", "author": [ { "family_name": "Porsandeh Khial", "given_name": "Parham", "orcid": "0000-0002-3242-8541", "clpid": "Porsandeh-Khial-P" }, { "family_name": "White", "given_name": "Alexander D.", "orcid": "0000-0002-5387-310X", "clpid": "White-A-D" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Optical gyroscopes measure the rate of rotation by exploiting a relativistic phenomenon known as the Sagnac effect. Such gyroscopes are great candidates for miniaturization onto nanophotonic platforms. However, the signal-to-noise ratio of optical gyroscopes is generally limited by thermal fluctuations, component drift and fabrication mismatch. Due to the comparatively weaker signal strength at the microscale, integrated nanophotonic optical gyroscopes have not been realized so far. Here, we demonstrate an all-integrated nanophotonic optical gyroscope by exploiting the reciprocity of passive optical networks to significantly reduce thermal fluctuations and mismatch. The proof-of-concept device is capable of detecting phase shifts 30 times smaller than state-of-the-art miniature fibre-optic gyroscopes, despite being 500 times smaller in size. Thus, our approach is capable of enhancing the performance of optical gyroscopes by one to two orders of magnitude.", "doi": "10.1038/s41566-018-0266-5", "issn": "1749-4885", "publisher": "Nature Publishing Group", "publication": "Nature Photonics", "publication_date": "2018-11", "series_number": "11", "volume": "12", "issue": "11", "pages": "671-675" }, { "id": "authors:yeccs-mnz21", "collection": "authors", "collection_id": "yeccs-mnz21", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180927-080601652", "type": "article", "title": "A 1-D heterodyne lens-free optical phased array camera with reference phase shifting", "author": [ { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Fatemi", "given_name": "Reza", "orcid": "0000-0001-9081-2608", "clpid": "Fatemi-R" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper presents the first integrated silicon photonics optical phased array (OPA) receiver with imaging capabilities. A 32-element 1D OPA with an overall aperture size of 96x50 \u03bcm^2 is used to generate an electrically steerable \"gazing beam\". The OPA receiver elements couple the incident light to on-chip waveguides which is processed as a phased array receiver. To minimize signal loss and enhance sensitivity, a heterodyne architecture with phase shifters in the local reference path is utilized. The OPA receiver can provide fully programmable angular selectivity with a grating-lobe-free field-of-view of 30\u00b0 and a gazing beamwidth of 0.74\u00b0.", "doi": "10.1109/JPHOT.2018.2871823", "issn": "1943-0655", "publisher": "IEEE", "publication": "IEEE Photonics Journal", "publication_date": "2018-10", "series_number": "5", "volume": "10", "issue": "5", "pages": "Art. No. 6601712" }, { "id": "authors:jzac5-r4q89", "collection": "authors", "collection_id": "jzac5-r4q89", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181025-114426172", "type": "book_section", "title": "A Coupled Inductive Bridge for Magnetic Sensing Applications", "book_title": "IEEE 44th European Solid State Circuits Conference", "author": [ { "family_name": "Gal-Katziri", "given_name": "Matan", "orcid": "0000-0001-9100-1188", "clpid": "Gal-Katziri-M" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A highly-sensitive magnetic sensor with excellent long-term stability is presented. We modify a conventional all-inductor AC Wheatstone Bridge by coupling two inductor pairs in a cross-coupled configuration which halves its size and doubles its sensitivity, while maintaining a fully differential output that reduces common-mode induced offset and drift. The sensor was fabricated with integrated excitation and receiver circuitry in a 65nm bulk CMOS process. It operates between 770MHz and 1.45GHz, has an effective sensing area of 200\u00b5m \u00d7 200\u00b5m, and reliably and continuously detects single 4.5\u00b5m magnetic label beads without significant drift over time periods notably longer than previously reported works. To our best knowledge, this is the first demonstration of a magnetic sensor using a fully symmetric, gain enhanced, and all-inductor coupled bridge circuit.", "doi": "10.1109/ESSCIRC.2018.8494313", "isbn": "978-1-5386-5404-0", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2018-09", "pages": "342-345" }, { "id": "authors:kcef9-q5190", "collection": "authors", "collection_id": "kcef9-q5190", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200103-130914658", "type": "book_section", "title": "Proximal-Field Radiation Sensors for Millimeter-Wave Integrated Radiators", "book_title": "2018 IEEE Radio Frequency Integrated Circuits Symposium (RFIC)", "author": [ { "family_name": "Safaripour", "given_name": "Amirreza", "orcid": "0000-0001-9758-6156", "clpid": "Safaripour-A" }, { "family_name": "Asghari", "given_name": "Bahar", "clpid": "Asghari-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Integration of Proximal-Field Radiation Sensors (PFRS) with mm-wave integrated radiators enables extraction of valuable information about their far-field radiation properties from the surface waves inside the substrate and the electromagnetic fields in close proximity of the radiating antennas. In this paper, we present a 72 GHz 2\u00d71 integrated radiator array with four on-chip PFRS units to show proximal-field sensing capability in calculation of far-field radiation properties solely through on-chip measurement of proximal fields.", "doi": "10.1109/RFIC.2018.8429018", "isbn": "9781538645451", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2018-06", "pages": "256-259" }, { "id": "authors:8tte6-1ma75", "collection": "authors", "collection_id": "8tte6-1ma75", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200103-130516403", "type": "book_section", "title": "A Low Power PWM Optical Phased Array Transmitter with 16\u00b0 Field-of-View and 0.8\u00b0 Beamwidth", "book_title": "2018 IEEE Radio Frequency Integrated Circuits Symposium (RFIC)", "author": [ { "family_name": "Fatemi", "given_name": "Reza", "orcid": "0000-0001-9081-2608", "clpid": "Fatemi-R" }, { "family_name": "Khachaturian", "given_name": "Aroutin", "orcid": "0000-0001-8304-3302", "clpid": "Khachaturian-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "An optical phased array (OPA) transmitter system with a high-swing electrical PWM driver achieving the highest reported grating-lobe-free field-of-view to beamwidth ratio of 16\u00b0/0.8\u00b0 for a two-dimensional aperture is presented. This ratio translates to 400 resolvable spots-which is 30x more numerous than the state-of-the-art. This scalable OPA, with a sparsely populated aperture, overcomes optical routing difficulties in planar photonic processes while maintaining the desired transmitter beam characteristics. To reduce the power consumption, a row-column electrical connection grid for the 144 optical phase shifters decreases the number of electrical drivers from 144 to 37. The PWM driver chip incorporates a breakdown-voltage multiplying architecture to increase the output voltage swing. The 65nm CMOS electronic driver chip and the photonic chip, fabricated through a standard silicon photonics process, occupy 1.7mm\u00b2 and 2.08mm\u00b2 of active area respectively.", "doi": "10.1109/rfic.2018.8428847", "isbn": "9781538645451", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2018-06", "pages": "28-31" }, { "id": "authors:p05hy-rjp75", "collection": "authors", "collection_id": "p05hy-rjp75", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181210-140402265", "type": "book_section", "title": "Ultralight Energy Converter Tile for the Space Solar Power Initiative", "book_title": "2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC)", "author": [ { "family_name": "Kelzenberg", "given_name": "Michael D.", "orcid": "0000-0002-6249-2827", "clpid": "Kelzenberg-M-D" }, { "family_name": "Espinet-Gonz\u00e1lez", "given_name": "Pilar", "orcid": "0000-0002-7656-0077", "clpid": "Espinet-Gonz\u00e1lez-P" }, { "family_name": "Vaidya", "given_name": "Nina", "clpid": "Vaidya-N" }, { "family_name": "Warmann", "given_name": "Emily C.", "orcid": "0000-0002-2810-4608", "clpid": "Warmann-E-C" }, { "family_name": "Naqavi", "given_name": "Ali", "clpid": "Naqavi-A" }, { "family_name": "Loke", "given_name": "Samuel P.", "clpid": "Loke-S-P" }, { "family_name": "Saive", "given_name": "Philipp", "clpid": "Saive-P" }, { "family_name": "Roy", "given_name": "Tatiana A.", "clpid": "Roy-T-A" }, { "family_name": "Vinogradova", "given_name": "Tatiana G.", "clpid": "Vinogradova-T-G" }, { "family_name": "Leclerc", "given_name": "Christophe", "clpid": "Leclerc-C" }, { "family_name": "Gdoutos", "given_name": "Eleftherios E.", "clpid": "Gdoutos-E-E" }, { "family_name": "Royer", "given_name": "Fabien", "clpid": "Royer-F" }, { "family_name": "Fikes", "given_name": "Austin", "clpid": "Fikes-A-C" }, { "family_name": "Bohn", "given_name": "Florian", "clpid": "Bohn-F" }, { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Hashemi", "given_name": "Mohammed R.", "clpid": "Hashemi-M-R" }, { "family_name": "Gal-Katziri", "given_name": "Matan", "orcid": "0000-0001-9100-1188", "clpid": "Gal-Katziri-M" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Pellegrino", "given_name": "Sergio", "orcid": "0000-0001-9373-3278", "clpid": "Pellegrino-S" }, { "family_name": "Atwater", "given_name": "Harry A.", "orcid": "0000-0001-9435-0201", "clpid": "Atwater-H-A" } ], "abstract": "We have fabricated a functional prototype of an ultralight power converter tile; a modular building block for a space-based solar power system. The tile is \u223c10\u00d715 cm in area, and weighs \u223c1.5 kg/m^2. It comprises a photovoltaic (PV) solar energy collector, a radio-frequency (RF) power converter, and an array of transmission antennas. The PV collector subassembly utilizes \u223c15x, 1D parabolic trough reflective concentrators with triple-junction (3J) solar cells. It has areal mass of \u223c0.8 kg/m^2, 74% optical efficiency, and a peak specific power of \u223c230W/kg. We demonstrated wireless power transmission over a distance of \u223c50 cm in our lab. Analysis of the sources of mass and inefficiency suggest a path towards achieving dramatically higher performance with future designs.", "doi": "10.1109/pvsc.2018.8547403", "isbn": "9781538685297", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2018-06", "pages": "3357-3359" }, { "id": "authors:jbtxr-geg41", "collection": "authors", "collection_id": "jbtxr-geg41", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180817-160152672", "type": "monograph", "title": "Three Dimensional Aggregation of Magnetic Particles", "author": [ { "family_name": "Pai", "given_name": "Alex", "clpid": "Pai-Alex" }, { "family_name": "Ho", "given_name": "Dimitar", "clpid": "Ho-Dimitar" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Magnetic drug delivery is a promising therapeutic because of magnetic fields' ability to permeate unperturbed in human tissue. One of the long-standing challenges in magnetic drug delivery is the inability to generate 3D aggregation non-invasively within the interior of the body. Earnshaw's theorem, which proves the impossibility of creating an energetic minimum in a curl-free and divergence-free field such as a magnetic field. However, one of the assumptions of Earnshaw's theorem is a static field. Here we show that it is possible to utilize a dynamically changing field and a dissipative force such as the drag, which is generally present, to create a stable aggregation point for magnetic particles. We also introduce a theoretical framework for designing the suitable magnetic fields for controlling a given magnetic particle in a particular fluid. This framework enables accurate determination of the necessary parameters for aggregation across a wide variety of magnetic particles and across multiple biologically-relevant fluids. By coating magnetic particles with desired therapeutic agents or attaching them to cells, a new class of treatment methodologies can be created in therapies such as targeted drug delivery and cell-based therapies. By dynamically changing the aggregation point, agents can also be guided along a particular path in the body. This technique of using dissipative forces to create a stable 3D aggregation point for particles could possibly be extended to a broad range of applications such as microscopic and macroscopic manipulation, robotics, guided self-assembly, magnetic plasma confinement, tissue engineering, and ion traps for quantum computers.", "doi": "10.48550/arXiv.1804.02778", "publisher": "arXiv", "publication_date": "2018-04-09" }, { "id": "authors:nys2v-gbb77", "collection": "authors", "collection_id": "nys2v-gbb77", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190827-111648684", "type": "book_section", "title": "Lensless imaging using silicon photonics optical phased arrays receivers (Conference Presentation)", "book_title": "Silicon Photonics XIII", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "contributor": [ { "family_name": "Reed", "given_name": "Graham T.", "clpid": "Reed-G-T" }, { "family_name": "Knights", "given_name": "Andrew P.", "clpid": "Knights-A-P" } ], "abstract": "The ability to integrate optical phased arrays (OPA) on a single silicon-photonics substrate offers a plethora of new opportunities in various fields, including projection and imaging. In this paper, we will discuss some of the trade-offs in the design of OPAs and their application. We investigate OPA receivers which can form and electronically steer a \"gazing beam\" in a desired direction. We will discuss various architectural and systems choices and present a one-dimensional (1D) OPA and a two dimensional (2D) OPA, as examples. We will demonstrate how an optical heterodyning approach can be used to improve the sensitivity of such OPA and form images directly from the surface of a silicon nano-photonic chip without any lens, additional optical components, or moving parts. We will discuss the design details of a 1D OPA RX camera with a field of view in excess of 60 with a gazing beam width of 0.74 based on a heterodyning architecture. We will also investigate the details of the design of a heterodyne 2D OPA lensless camera which can image with the gazing beam width of 0.75 and the ability to image a field of view of roughly 8 in azimuth and elevation. We will also discuss the concept and implementation of coherent imagers that can be used as highly precise 3D imagers. As an example, we will show 3D imaging at the distance of 0.5m with a resolution of 15um.", "doi": "10.1117/12.2293192", "isbn": "9781510615595", "publisher": "Society of Photo-Optical Instrumentation Engineers (SPIE)", "place_of_publication": "Bellingham, WA", "publication_date": "2018-03-14", "pages": "Art. No. 105370C" }, { "id": "authors:0d6be-j1q10", "collection": "authors", "collection_id": "0d6be-j1q10", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180412-125250249", "type": "book_section", "title": "A 69-to-79GHz CMOS multiport PA/radiator with +35.7dBm CW EIRP and integrated PLL", "book_title": "2018 IEEE International Solid - State Circuits Conference - (ISSCC)", "author": [ { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Low-cost mm-wave silicon integrated signal generation and processing enable many applications, such as silicon-based automotive radars for self-driving cars and wireless communications. Some challenges encountered in commercialization of such systems are the high packaging and testing costs and high sensitivity to antenna parameters, which can diminish the advantage of integrated silicon solutions. On-chip antennas have been proposed as a solution to reduce the packaging costs [1,2]. Link budget analysis of systems (e.g., radar) necessitates high-power (high EIRP) transmitters while system resolution analysis suggests higher frequency of operation for better spatial resolution. The scaling of CMOS transistors facilitates the latter requirement, but, unfortunately, the lower breakdown voltage of the transistors reduces their maximum power handling capabilities at a given radiator impedance. Several approaches have already been implemented to address this issue, each with its own shortcoming. Power-combining multiple PA outputs with passive on-chip power combiners [3] adds extra loss and reduces the overall efficiency, spatial power combining using phased arrays [4] consumes a large die area. Power combining at the antenna [5,6] has been proposed as an approach to address these challenges. In this paper, we propose a spatial PA/radiator power combining approach with optimal PA-load design using strongly coupled antennas in close proximity. This approach utilizes techniques of power combining in free space resulting in favorable drive-point impedance design and using on-chip PAs and radiators to achieve high radiated output power.", "doi": "10.1109/ISSCC.2018.8310355", "isbn": "978-1-5090-4940-0", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2018-02", "pages": "404-406" }, { "id": "authors:05x7s-t4p25", "collection": "authors", "collection_id": "05x7s-t4p25", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180412-104241139", "type": "book_section", "title": "A 0.3ppm dual-resonance transformer-based drift-cancelling reference-free magnetic sensor for biosensing applications", "book_title": "2018 IEEE International Solid - State Circuits Conference - (ISSCC)", "author": [ { "family_name": "Sideris", "given_name": "Constantine", "orcid": "0000-0002-3042-4889", "clpid": "Sideris-C" }, { "family_name": "Porsandeh Khial", "given_name": "Parham", "orcid": "0000-0002-3242-8541", "clpid": "Porsandeh-Khial-P" }, { "family_name": "Ling", "given_name": "Bill", "orcid": "0000-0002-1276-7204", "clpid": "Ling-Bill" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Cost-efficient, point-of-use diagnostics are critical for early disease detection. Traditionally, the majority of lab-based analysis equipment utilizes fluorescent markers for biodetection assays. However, magnetic-based labels have recently been shown to be promising alternatives to fluorescent tags for DNA, protein, and cell assays. Magnetic assays offer several key advantages over their fluorescent counterparts, namely that magnetic beads do not suffer from signal decay due to bleaching and that they can be detected with cheap CMOS-based sensors, eliminating the need for expensive lasers, photo-diodes, filters, and complicated post-processing steps. Significant progress has recently been made in the design of magnetic imager ICs, such as [1] which utilizes a gMr approach for detection and [2-4] which measure the resonance shift in an LC tank.", "doi": "10.1109/ISSCC.2018.8310248", "isbn": "978-1-5090-4940-0", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2018-02", "pages": "190-192" }, { "id": "authors:4afjx-yfv11", "collection": "authors", "collection_id": "4afjx-yfv11", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190805-134837271", "type": "book_section", "title": "A lightweight tile structure integrating photovoltaic conversion and RF power transfer for space solar power applications", "book_title": "AIAA Scitech 2018 Forum", "author": [ { "family_name": "Gdoutos", "given_name": "Eleftherios E.", "clpid": "Gdoutos-E-E" }, { "family_name": "Leclerc", "given_name": "Christophe", "clpid": "Leclerc-C" }, { "family_name": "Royer", "given_name": "Fabien", "clpid": "Royer-F" }, { "family_name": "Kelzenberg", "given_name": "Michael D.", "orcid": "0000-0002-6249-2827", "clpid": "Kelzenberg-M-D" }, { "family_name": "Warmann", "given_name": "Emily C.", "orcid": "0000-0002-2810-4608", "clpid": "Warmann-E-C" }, { "family_name": "Espinet-Gonz\u00e1lez", "given_name": "Pilar", "orcid": "0000-0002-7656-0077", "clpid": "Espinet-Gonz\u00e1lez-P" }, { "family_name": "Vaidya", "given_name": "Nina", "clpid": "Vaidya-N" }, { "family_name": "Bohn", "given_name": "Florian", "clpid": "Bohn-F" }, { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Hashemi", "given_name": "Mohammed R.", "clpid": "Hashemi-M-R" }, { "family_name": "Gal-Katziri", "given_name": "Matan", "orcid": "0000-0001-9100-1188", "clpid": "Gal-Katziri-M" }, { "family_name": "Fikes", "given_name": "Austin", "clpid": "Fikes-A-C" }, { "family_name": "Atwater", "given_name": "Harry A.", "orcid": "0000-0001-9435-0201", "clpid": "Atwater-H-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Pellegrino", "given_name": "Sergio", "orcid": "0000-0001-9373-3278", "clpid": "Pellegrino-S" } ], "abstract": "We demonstrate the development of a prototype lightweight (1.5 kg/m^3) tile structure capable of photovoltaic solar power capture, conversion to radio frequency power, and transmission through antennas. This modular tile can be repeated over an arbitrary area to forma large aperture which could be placed in orbit to collect sunlight and transmit electricity to any location. Prototype design is described and validated through finite element analysis, and high-precision ultra-light component manufacture and robust assembly are described.", "doi": "10.2514/6.2018-2202", "isbn": "9781624105302", "publisher": "AIAA", "place_of_publication": "Reston, VA", "publication_date": "2018-01-08", "pages": "Art. No. 2018-2202" }, { "id": "authors:3jj5p-h3q02", "collection": "authors", "collection_id": "3jj5p-h3q02", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170929-075014830", "type": "article", "title": "Self-equalizing photodiodes, a hybrid electro-optical approach to tackle bandwidth limitation in high-speed signaling", "author": [ { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Aflatouni", "given_name": "Firooz", "clpid": "Aflatouni-F" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "In this paper we provide the design details of self-equalizing photodetectors which enable higher data rate transmission by improving the overall bandwidth of the bandwidth limited transmission link, through a hybrid electro-optical solution. Two different self-equalizing photodiodes, one having fixed equalization and the other being programmable are presented as proof of concept.", "doi": "10.1364/OE.25.019137", "issn": "1094-4087", "publisher": "Optical Society of America", "publication": "Optics Express", "publication_date": "2017-08-07", "series_number": "16", "volume": "25", "issue": "16", "pages": "19137-19146" }, { "id": "authors:xzx6p-ems21", "collection": "authors", "collection_id": "xzx6p-ems21", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181109-081714215", "type": "book_section", "title": "Near-unity ultra-wideband thermal infrared emission for space solar power radiative cooling", "book_title": "2017 IEEE 44th Photovoltaic Specialist Conference (PVSC)", "author": [ { "family_name": "Naqavi", "given_name": "Ali", "clpid": "Naqavi-A" }, { "family_name": "Loke", "given_name": "Samuel P.", "clpid": "Loke-S-P" }, { "family_name": "Kelzenberg", "given_name": "Michael D.", "orcid": "0000-0002-6249-2827", "clpid": "Kelzenberg-M-D" }, { "family_name": "Warmann", "given_name": "Emily C.", "orcid": "0000-0002-2810-4608", "clpid": "Warmann-E-C" }, { "family_name": "Espinet-Gonz\u00e1lez", "given_name": "Pilar", "orcid": "0000-0002-7656-0077", "clpid": "Espinet-Gonz\u00e1lez-P" }, { "family_name": "Vaidya", "given_name": "Nina", "clpid": "Vaidya-N" }, { "family_name": "Huang", "given_name": "Jing-Shun", "orcid": "0000-0002-7531-4691", "clpid": "Huang-Jing-Shun" }, { "family_name": "Roy", "given_name": "Tatiana A.", "clpid": "Roy-T-A" }, { "family_name": "Messer", "given_name": "Alexander J.", "clpid": "Messer-A-J" }, { "family_name": "Vinogradova", "given_name": "Tatiana G.", "clpid": "Vinogradova-T-G" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Pellegrino", "given_name": "Sergio", "orcid": "0000-0001-9373-3278", "clpid": "Pellegrino-S" }, { "family_name": "Atwater", "given_name": "Harry A.", "orcid": "0000-0001-9435-0201", "clpid": "Atwater-H-A" } ], "abstract": "We report the design, fabrication and characterization of ultrathin metasurfaces that exhibit wideband 300 K thermal emissivity. The emissive behavior of these structures is almost independent of the emission angle. Our ultralight subwavelength-thickness metasurfaces can be fabricated relatively easily and are excellent candidates for radiative cooling in space applications.", "doi": "10.1109/PVSC.2017.8366597", "isbn": "978-1-5090-5605-7", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2017-06", "pages": "521-524" }, { "id": "authors:pj5qc-23d13", "collection": "authors", "collection_id": "pj5qc-23d13", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170712-150437498", "type": "book_section", "title": "Fully integrated CMOS X-Band power amplifier quad with current reuse and dynamic digital feedback (DDF) capabilities", "book_title": "2017 IEEE Radio Frequency Integrated Circuits Symposium (RFIC)", "author": [ { "family_name": "Bohn", "given_name": "Florian", "clpid": "Bohn-F" }, { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A 10GHz fully-integrated stacked PA quad with dynamic digital feedback and control loops provides total output power of 200mW at 37% PAE. It utilizes data provided by multiple on-chip sensors to maintain safe operating conditions and regulate the individual power PA power supply voltages and independent power control for each PA. This digitally controlled stacked PA quad with on-chip matching allows higher operation voltages while maintaining current consumption constant, leading to higher overall system efficiency, as ohmic drop losses under large supply-to-breakdown voltage ratios are reduced.", "doi": "10.1109/RFIC.2017.7969054", "isbn": "978-1-5090-4626-3", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2017-06", "pages": "208-211" }, { "id": "authors:jdpzz-92t89", "collection": "authors", "collection_id": "jdpzz-92t89", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20171012-160624981", "type": "book_section", "title": "Proximal-field radiation sensors", "book_title": "2017 IEEE MTT-S International Microwave Symposium", "author": [ { "family_name": "Safaripour", "given_name": "Amirreza", "orcid": "0000-0001-9758-6156", "clpid": "Safaripour-A" }, { "family_name": "Hashemi", "given_name": "Mohammed Reza M.", "orcid": "0000-0002-8908-0048", "clpid": "Hashemi-M-R-M" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Proximal-Field Radiation Sensors (PFRS) are introduced as a new set of tools to enable extraction of far-field radiation properties of integrated antennas from the surface waves inside their dielectric substrates. These sensors allow self-characterization, self-calibration, and self-monitoring of the radiation performance for both printed circuit board (PCB) antennas and integrated circuit (IC) antennas without any need to additional test equipment. In this paper, we explain how these sensors can be implemented and demonstrate how the far-field radiation properties can be determined from them. A PCB prototype consisting of two transmitting patch antennas and four integrated PFRS antennas is fabricated and tested to verify the concept and demonstrate the implemented sensors' capabilities to capture the radiation properties such as gain pattern, radiated polarization, and the steering angle of the antenna array as a few examples of radiation sensors applications.", "doi": "10.1109/MWSYM.2017.8058871", "isbn": "978-1-5090-6360-4", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2017-06", "pages": "1375-1378" }, { "id": "authors:hd7br-x6z92", "collection": "authors", "collection_id": "hd7br-x6z92", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181108-154443049", "type": "book_section", "title": "Design and Prototyping Efforts for the Space Solar Power Initiative", "book_title": "2017 IEEE 44th Photovoltaic Specialist Conference (PVSC)", "author": [ { "family_name": "Kelzenberg", "given_name": "Michael D.", "orcid": "0000-0002-6249-2827", "clpid": "Kelzenberg-M-D" }, { "family_name": "Espinet-Gonz\u00e1lez", "given_name": "Pilar", "orcid": "0000-0002-7656-0077", "clpid": "Espinet-Gonz\u00e1lez-P" }, { "family_name": "Vaidya", "given_name": "Nina", "clpid": "Vaidya-N" }, { "family_name": "Roy", "given_name": "Tatiana A.", "clpid": "Roy-T-A" }, { "family_name": "Warmann", "given_name": "Emily C.", "orcid": "0000-0002-2810-4608", "clpid": "Warmann-E-C" }, { "family_name": "Naqavi", "given_name": "Ali", "clpid": "Naqavi-A" }, { "family_name": "Loke", "given_name": "Samuel P.", "clpid": "Loke-S-P" }, { "family_name": "Huang", "given_name": "Jing-Shun", "orcid": "0000-0002-7531-4691", "clpid": "Huang-Jing-Shun" }, { "family_name": "Vinogradova", "given_name": "Tatiana G.", "clpid": "Vinogradova-T-G" }, { "family_name": "Messer", "given_name": "Alexander J.", "clpid": "Messer-A-J" }, { "family_name": "Leclerc", "given_name": "Christophe", "clpid": "Leclerc-C" }, { "family_name": "Gdoutos", "given_name": "Eleftherios E.", "clpid": "Gdoutos-E-E" }, { "family_name": "Royer", "given_name": "Fabien", "clpid": "Royer-F" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Pellegrino", "given_name": "Sergio", "orcid": "0000-0001-9373-3278", "clpid": "Pellegrino-S" }, { "family_name": "Atwater", "given_name": "Harry A.", "orcid": "0000-0001-9435-0201", "clpid": "Atwater-H-A" } ], "abstract": "The Space Solar Power Initiative (SSPI) seeks to enable reliable, cost-effective baseload power generation from large-scale solar power stations in space. We propose an ultralight, modular power station, having specific power in the range of 1\u201310 kW/kg for the photovoltaic (PV) collection subsystem. The building block of the power station is the 'tile,' a self-contained element that performs PV energy collection, conversion to radio frequency (RF), and transmission to earth. To minimize PV mass, we select a 1D, 10\u201320X parabolic trough concentrator geometry, which provides cooling and radiation shielding for the cells, and which folds flat for deployment. Here, we discuss the design, fabrication, and testing of the initial PV tile prototypes.", "doi": "10.1109/PVSC.2017.8366621", "isbn": "978-1-5090-5605-7", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2017-06", "pages": "558-561" }, { "id": "authors:2ep65-wns11", "collection": "authors", "collection_id": "2ep65-wns11", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170628-124450870", "type": "book_section", "title": "An 8x8 Heterodyne Lens-less OPA Camera", "book_title": "Conference on Lasers and Electro-Optics", "author": [ { "family_name": "Fatemi", "given_name": "Reza", "orcid": "0000-0001-9081-2608", "clpid": "Fatemi-R" }, { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper presents an 8x8 optical phased array (OPA) receiver that operates as a lens-less camera using a heterodyne architecture on a thin silicon-photonics integrated SOI substrate. It has a receiving beam width of 0.75\u00b0 and beam steering range of 8\u00b0.", "doi": "10.1364/CLEO_AT.2017.JW2A.9", "isbn": "978-1-943580-27-9", "publisher": "Optical Society of America (OSA)", "place_of_publication": "San Jose, CA", "publication_date": "2017-05", "pages": "Art. No. JW2A.9" }, { "id": "authors:ckk63-z0e22", "collection": "authors", "collection_id": "ckk63-z0e22", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170503-094736352", "type": "article", "title": "Analysis of a balanced analog multiplier for an arbitrary number of signed inputs", "author": [ { "family_name": "Hong", "given_name": "Brian", "orcid": "0000-0001-8099-0312", "clpid": "Hong-Brian" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "We present an extension of the double-balanced current-commutating analog multiplier (also known as the Gilbert cell) that enables the multiplication of an arbitrary number of signed differential input voltages. A general analysis of the circuit for an arbitrary device nonlinearity is provided, and simulations on a bulk CMOS process as well as measurement results of a discrete bipolar implementation are reported.", "doi": "10.1002/cta.2243", "issn": "0098-9886", "publisher": "Wiley", "publication": "International Journal of Circuit Theory and Applications", "publication_date": "2017-04", "series_number": "4", "volume": "45", "issue": "4", "pages": "483-501" }, { "id": "authors:hfm5x-7nq73", "collection": "authors", "collection_id": "hfm5x-7nq73", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170315-152158738", "type": "book_section", "title": "A 180-GHz CMOS down-converter MMIC for atmospheric remote sensing applications", "book_title": "IEEE 17th Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems (SiRF)", "author": [ { "family_name": "Parveg", "given_name": "Dristy", "clpid": "Parveg-D" }, { "family_name": "Varonen", "given_name": "Mikko", "clpid": "Varonen-M" }, { "family_name": "Safaripour", "given_name": "Amirreza", "orcid": "0000-0001-9758-6156", "clpid": "Safaripour-A" }, { "family_name": "Bowers", "given_name": "Steven", "clpid": "Bowers-S-M" }, { "family_name": "Tikka", "given_name": "Tero", "clpid": "Tikka-T" }, { "family_name": "Kangaslahti", "given_name": "Pekka", "clpid": "Kangaslahti-P" }, { "family_name": "Gaier", "given_name": "Todd", "clpid": "Gaier-T" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Halonen", "given_name": "Kari A. I.", "clpid": "Halonen-K-A-I" } ], "abstract": "In this paper, we study the feasibility of using CMOS circuit blocks for designing future light weight, small in size atmospheric remote sensing receivers. A compact CMOS down-converter is designed which operates from 160 to 188 GHz and includes a sub-harmonically pumped I/Q resistive mixer, two IF amplifiers and a voltage controlled oscillator (VCO) with LO buffer. A measured down-conversion gain of +2.6 dB is achieved with a total dc power consumption of 152 mW using the nominal supply of +1.2 V. The measurement results show a 3 dB IF bandwidth from 1 to 5 GHz and the VCO tuning range is from 85 to 89 GHz. The designed CMOS MMIC down-converter including the probing pads occupies a silicon area of 0.575 mm^2.", "doi": "10.1109/SIRF.2017.7874372", "isbn": "978-1-5090-5237-0", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2017-01", "pages": "64-67" }, { "id": "authors:hkff6-qbv73", "collection": "authors", "collection_id": "hkff6-qbv73", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160930-143636537", "type": "article", "title": "Binary particle swarm optimized 2 \u00d7 2 power splitters in a standard foundry silicon photonic platform", "author": [ { "family_name": "Mak", "given_name": "Jason C. C.", "orcid": "0000-0003-2350-5813", "clpid": "Mak-J-C-C" }, { "family_name": "Sideris", "given_name": "Constantine", "orcid": "0000-0002-3042-4889", "clpid": "Sideris-C" }, { "family_name": "Jeong", "given_name": "Junho", "clpid": "Jeong-Junho" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Poon", "given_name": "Joyce K. S.", "clpid": "Poon-J-K-S" } ], "abstract": "Compact power splitters designed ab initio using binary particle swarm optimization in a 2D mesh for a standard foundry silicon photonic platform are studied. Designs with a 4.8\u2009\u2009\u03bcm\u00d74.8\u2009\u2009\u03bcm footprint composed of 200\u2009\u2009nm\u00d7200\u2009\u2009nm and 100\u2009\u2009nm\u00d7100\u2009\u2009nm cells are demonstrated. Despite not respecting design rules, the design with the smaller cells had lower insertion losses and broader bandwidth and showed consistent behavior across the wafer. Deviations between design and experiments point to the need for further investigations of the minimum feature dimensions.", "doi": "10.1364/OL.41.003868", "issn": "0146-9592", "publisher": "Optical Society of America", "publication": "Optics Letters", "publication_date": "2016-08-15", "series_number": "16", "volume": "41", "issue": "16", "pages": "3868-3871" }, { "id": "authors:efptg-h6832", "collection": "authors", "collection_id": "efptg-h6832", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160802-080138135", "type": "article", "title": "Upper and lower bounds on a system's bandwidth based on its zero-value time constants", "author": [ { "family_name": "Hong", "given_name": "B.", "clpid": "Hong-B" }, { "family_name": "Hajimiri", "given_name": "A.", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "It is shown that for systems with no zeros and no complex poles, the classical estimate of the 3 dB cutoff frequency based on the sum of the zero-value time constants (ZVTs) is always conservative. A non-trivial upper bound on the cutoff frequency which depends only on the sum of the ZVTs and the system's order is also derived. It is demonstrated that both bounds are tight \u2013 specifically, the lower bound is approached by making one of the system's poles increasingly dominant, whereas the best possible bandwidth is achieved when all of the system's poles overlap. The impact of complex poles on the results is also discussed.", "doi": "10.1049/el.2016.1724", "issn": "0013-5194", "publisher": "Institution of Engineering and Technology", "publication": "Electronics Letters", "publication_date": "2016-08-04", "series_number": "16", "volume": "52", "issue": "16", "pages": "1383-1385" }, { "id": "authors:g1knm-dmc94", "collection": "authors", "collection_id": "g1knm-dmc94", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161014-084018774", "type": "article", "title": "Upper and lower bounds on a system's bandwidth based on its zero-value time constants", "author": [ { "family_name": "Hong", "given_name": "B.", "clpid": "Hong-Brian-D" }, { "family_name": "Hajimiri", "given_name": "A.", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "It is shown that for systems with no zeros and no complex poles, the classical estimate of the 3 dB cutoff frequency based on the sum of the zero-value time constants (ZVTs) is always conservative. The opposite problem is also solved, whereby a non-trivial upper bound on the cutoff frequency which depends only on the sum of the ZVTs and the system's order is derived. It is demonstrated that both bounds\nare tight \u2013 specifically, the lower bound is approached by making one of the system's poles increasingly dominant, whereas the best possible bandwidth is achieved when all of the system's poles overlap. The impact of complex poles on the results is also discussed.", "doi": "10.1049/e1.2016.1724", "issn": "0013-5194", "publisher": "Institution of Engineering and Technology (IET)", "publication": "Electronics Letters", "publication_date": "2016-08-04", "series_number": "16", "volume": "52", "issue": "16", "pages": "1383-1384" }, { "id": "authors:4f2xp-t3e22", "collection": "authors", "collection_id": "4f2xp-t3e22", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160825-104818056", "type": "article", "title": "Designing Optimal Surface Currents for Efficient On-Chip mm-Wave Radiators With Active Circuitry", "author": [ { "family_name": "Sengupta", "given_name": "Kaushik", "clpid": "Sengupta-K" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Integrated antennas have become the attractive solution as the electromagnetic (EM) interface for mm-Wave and terahertz ICs. However, on-chip antennas lying at the interface between two different dielectrics (such as air and substrate) can channel most of its power into multiple nonradiative surface-wave modes, reducing efficiency drastically. In this paper, we consider the following problem: given a dielectric substrate, what is the theoretical optimal 2-D surface-current configuration that collectively suppresses surface waves and maximizes radiation efficiency with the desirable radiation pattern? This paper also discusses demonstrative examples of a circuit-EM codesign approach to realize the approximation of such current configurations. Measurement results of radiating arrays in CMOS at mm-Wave frequencies (250-300 GHz) are presented and compared with theoretical predictions.", "doi": "10.1109/TMTT.2016.2573278", "issn": "0018-9480", "publisher": "IEEE", "publication": "IEEE Transactions on Microwave Theory and Techniques", "publication_date": "2016-07", "series_number": "7", "volume": "64", "issue": "7", "pages": "1976-1988" }, { "id": "authors:epd77-b4z42", "collection": "authors", "collection_id": "epd77-b4z42", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170111-132036140", "type": "book_section", "title": "A One-Dimensional Heterodyne Lens-Free OPA Camera", "book_title": "Conference on Lasers and Electro-Optics 2016", "author": [ { "family_name": "Fatemi", "given_name": "Reza", "orcid": "0000-0001-9081-2608", "clpid": "Fatemi-R" }, { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper presents a thin silicon-photonics integrated one-dimensional lens-free camera based on an optical phased array receiver on an SOI process. The camera has beam steering range in excess of 60\u00b0 with no blind spots, a beam width of 0.74\u00b0, and is used to form images.", "doi": "10.1364/CLEO_SI.2016.STu3G.3", "isbn": "978-1-943580-11-8", "publisher": "Optical Society of America (OSA)", "place_of_publication": "Washington, DC", "publication_date": "2016-06", "pages": "Art. No. STu3G.3" }, { "id": "authors:v8v73-xwv09", "collection": "authors", "collection_id": "v8v73-xwv09", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160602-142331678", "type": "article", "title": "CMOS I/Q Subharmonic Mixer for Millimeter-Wave Atmospheric Remote Sensing", "author": [ { "family_name": "Parveg", "given_name": "Dristy", "clpid": "Parveg-D" }, { "family_name": "Varonen", "given_name": "Mikko", "clpid": "Varonen-M" }, { "family_name": "Kangaslahti", "given_name": "Pekka", "clpid": "Kangaslahti-P" }, { "family_name": "Safaripour", "given_name": "Amirreza", "orcid": "0000-0001-9758-6156", "clpid": "Safaripour-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Tikka", "given_name": "Tero", "clpid": "Tikka-T" }, { "family_name": "Gaier", "given_name": "Todd", "clpid": "Gaier-T" }, { "family_name": "Halonen", "given_name": "Kari A. I.", "clpid": "Halonen-K-A-I" } ], "abstract": "A compact second harmonic 180 GHz I/Q balanced resistive mixer is realized in a 32-nm SOI CMOS technology for atmospheric remote sensing applications. The MMIC further includes two on-chip IF amplifiers at the mixer's I and Q channels. A conversion gain of +8 dB is achieved with 74 mW of dc power consumption using a 1.2 V supply. The measured IF frequency range is from 1 to 10 GHz. The mixer achieves a 20 dB imagerejection (IR) ratio with an LO input power of +4 dBm. The chip size is 0.75 mm^2 including probing pads.", "doi": "10.1109/LMWC.2016.2537786", "issn": "1531-1309", "publisher": "IEEE", "publication": "IEEE Microwave and Wireless Components Letters", "publication_date": "2016-04", "series_number": "4", "volume": "26", "issue": "4", "pages": "285-287" }, { "id": "authors:a457j-1rf46", "collection": "authors", "collection_id": "a457j-1rf46", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160512-123859956", "type": "article", "title": "Dynamic Polarization Control of Two-Dimensional Integrated Phased Arrays", "author": [ { "family_name": "Safaripour", "given_name": "Amirreza", "orcid": "0000-0001-9758-6156", "clpid": "Safaripour-A" }, { "family_name": "Bowers", "given_name": "Steven M.", "clpid": "Bowers-S-M" }, { "family_name": "Dasgupta", "given_name": "Kaushik", "clpid": "Dasgupta-K" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Simultaneous two-dimensional (2-D) beam steering and dynamic polarization control (DPC) of the radiated electric field in 2-D phased arrays ensure polarization matching between the transmitter and receiver antennas in both fixed and mobile wireless systems. Polarization matching is maintained regardless of the polarization, orientation, and location of the receiver antenna in space within the 2-D steering range of the transmitter. This work implements a fully integrated 2 \u00d7 2 DPC phased-array transmitter in a 32-nm CMOS silicon-on-insulator process, radiating at 122.9 GHz. It achieves a maximum effective isotropic radiated power of +12.3 dBm in the broadside direction and enables polarization angle control of the radiated linear and elliptical polarizations across the full range of 0 \u00b0 to 180 \u00b0 with tunable axial ratio down to 1.2 dB to achieve circular polarization and the ability to steer the radiated beam up to 15 \u00b0 in both dimensions.", "doi": "10.1109/TMTT.2016.2530704", "issn": "0018-9480", "publisher": "IEEE", "publication": "IEEE Transactions on Microwave Theory and Techniques", "publication_date": "2016-04", "series_number": "4", "volume": "64", "issue": "4", "pages": "1066-1077" }, { "id": "authors:yjv2a-kpz24", "collection": "authors", "collection_id": "yjv2a-kpz24", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170111-150941985", "type": "article", "title": "200-GHz CMOS amplifier with 9-dB noise figure for atmospheric remote sensing", "author": [ { "family_name": "Varonen", "given_name": "M.", "clpid": "Varonen-M" }, { "family_name": "Safaripour", "given_name": "A.", "orcid": "0000-0001-9758-6156", "clpid": "Safaripour-A" }, { "family_name": "Parveg", "given_name": "D.", "clpid": "Parveg-D" }, { "family_name": "Kangaslahti", "given_name": "P.", "clpid": "Kangaslahti-P" }, { "family_name": "Gaier", "given_name": "T.", "clpid": "Gaier-T" }, { "family_name": "Hajimiri", "given_name": "A.", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "The feasibility of using CMOS technology for RF amplification in atmospheric remote sensing receiver is studied. The design and measurement results of a 200-GHz low-noise amplifier which is fabricated using a 32-nm SOI CMOS technology are presented. The 8-stage amplifier in a common-source configuration achieves a 9-dB noise figure and 25-dB gain with a power consumption of 33 mW.", "doi": "10.1049/el.2015.3337", "issn": "0013-5194", "publisher": "IET", "publication": "Electronics Letters", "publication_date": "2016-02-25", "series_number": "5", "volume": "52", "issue": "5", "pages": "369-371" }, { "id": "authors:a3dgv-tk387", "collection": "authors", "collection_id": "a3dgv-tk387", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151124-075124643", "type": "book_section", "title": "Monolithic Mach-Zehnder Interferometer Modulator in an unmodified CMOS process", "author": [ { "family_name": "Khachaturian", "given_name": "Aroutin", "orcid": "0000-0001-8304-3302", "clpid": "Khachaturian-A" }, { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Zhou", "given_name": "Andy", "clpid": "Zhou-Andy" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A compact monolithically integrated Mach-Zehnder Interferometer Modulator operating above 1Gbps is demonstrated in an unmodified 180nm CMOS SOI process. This 50\u00b5m long structure allows for high density integration of photonics modulators and electrical driver circuitry on a single standard CMOS chip.", "doi": "10.1109/IPCon.2015.7323627", "publisher": "IEEE", "publication_date": "2015-10" }, { "id": "authors:rks3h-8rz16", "collection": "authors", "collection_id": "rks3h-8rz16", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20201019-074355743", "type": "book_section", "title": "Cell-culturing, imaging, and magnetic manipulation using a compact 3D printed chamber", "author": [ { "family_name": "Pai", "given_name": "Alex", "clpid": "Pai-Alex" }, { "family_name": "Pailevaniant", "given_name": "Torkom", "clpid": "Pailevaniant-Torkom" }, { "family_name": "White", "given_name": "Ethan", "clpid": "White-E-E" }, { "family_name": "Dasgupta", "given_name": "Kaushik", "clpid": "Dasgupta-Kaushik" }, { "family_name": "Sherman", "given_name": "Jeff", "clpid": "Sherman-Jeff" }, { "family_name": "Alizadeh", "given_name": "Darya", "clpid": "Alizadeh-Darya" }, { "family_name": "Cao", "given_name": "Pengpeng", "clpid": "Cao-Pengpeng" }, { "family_name": "Berlin", "given_name": "Jacob M.", "orcid": "0000-0001-7498-766X", "clpid": "Berlin-J-M" }, { "family_name": "Badie", "given_name": "Behnam", "clpid": "Badie-Behnam" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "[no abstract]", "publisher": "Curran Associates", "publication_date": "2015-10" }, { "id": "authors:qn6nw-7h674", "collection": "authors", "collection_id": "qn6nw-7h674", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151216-105345451", "type": "book_section", "title": "Differential Optical Ring Modulator: Breaking the Bandwidth/Quality-factor Trade-off", "author": [ { "family_name": "Saeedi", "given_name": "Saman", "clpid": "Saeedi-S" }, { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Emami", "given_name": "Azita", "orcid": "0000-0002-6945-9958", "clpid": "Emami-A" } ], "abstract": "We present a differential ring modulator that breaks the optical bandwidth/quality factor trade-off known to limit the speed of high-Q ring modulators. This structure maintains a constant energy in the ring to avoid pattern-dependent power droop.", "doi": "10.1109/ECOC.2015.7341731", "publisher": "IEEE", "publication_date": "2015-10" }, { "id": "authors:1rszz-fb870", "collection": "authors", "collection_id": "1rszz-fb870", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151012-154703698", "type": "article", "title": "Mutual Synchronization for Power Generation and Beam-Steering in CMOS With On-Chip Sense Antennas Near 200 GHz", "author": [ { "family_name": "Sengupta", "given_name": "Kaushik", "clpid": "Sengupta-K" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "In this paper, we introduce the concept of near-field synchronization as an efficient, scalable, and robust method to synchronize a 2-D array of mutually coupled oscillators for beam-forming at frequencies above f_(max) of a technology. The method employs an array of on-chip sense antennas to probe electromagnetic near-fields of the on-chip radiators. These sense antennas are then coupled to each other appropriately through a network that establishes the synchronized state as the lowest energy state. A circuit-electromagnetic co-design methodology is employed to demonstrate beam-steering near 200 GHz with a synchronized 2 \u00d7 2 array. Each element of the array is a traveling-wave oscillator with the nonlinear active devices selectively radiating its second harmonic through the same electromagnetic structure. The beam-pattern can be varied by more than 70\u00b0 in both azimuth and elevation. The chip is realized in 65-nm bulk CMOS.", "doi": "10.1109/TMTT.2015.2457902", "issn": "0018-9480", "publisher": "IEEE", "publication": "IEEE Transactions on Microwave Theory and Techniques", "publication_date": "2015-09", "series_number": "9", "volume": "63", "issue": "9", "pages": "2867-2876" }, { "id": "authors:jk49n-ay157", "collection": "authors", "collection_id": "jk49n-ay157", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151001-111516703", "type": "article", "title": "Nanophotonic projection system", "author": [ { "family_name": "Aflatouni", "given_name": "Firooz", "clpid": "Aflatouni-F" }, { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Rekhi", "given_name": "Angad", "clpid": "Rekhi-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Low-power integrated projection technology can play a key role in development of low-cost mobile devices with built-in high-resolution projectors. Low-cost 3D imaging and holography systems are also among applications of such a technology. In this paper, an integrated projection system based on a two-dimensional optical phased array with fast beam steering capability is reported. Forward biased p-i-n phase modulators with 200MHz bandwidth are used per each array element for rapid phase control. An optimization algorithm is implemented to compensate for the phase dependent attenuation of the p-i-n modulators. Using rapid vector scanning technique, images were formed and recorded within a single snapshot of the IR camera.", "doi": "10.1364/OE.23.021012", "issn": "1094-4087", "publisher": "Optical Society of America", "publication": "Optics Express", "publication_date": "2015-08-10", "series_number": "16", "volume": "23", "issue": "16", "pages": "21012-21022" }, { "id": "authors:td1rs-39e74", "collection": "authors", "collection_id": "td1rs-39e74", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151028-075948528", "type": "book_section", "title": "Hybrid Silicon Photonics and Electronics Solutions for Communications, Sensing, and Imaging", "book_title": "2015 IEEE 12th International Conference on Group IV Photonics (GFP)", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Silicon photonics offer large bandwidths and low-loss delay, while integrated electronics can provide gain and complex signal processing with much lower overhead. Here, we will discuss a few examples of such hybrid solutions to demonstrate the potential of a more holistic approach to silicon integrated systems.", "doi": "10.1109/Group4.2015.7305902", "isbn": "978-1-4799-8254-7", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2015-08", "pages": "193-194" }, { "id": "authors:hnbk2-w6c54", "collection": "authors", "collection_id": "hnbk2-w6c54", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151028-075731448", "type": "book_section", "title": "A compact spiral Mach-Zehnder Interferometer Modulator on SOI process", "book_title": "2015 IEEE 12th International Conference on Group IV Photonics (GFP)", "author": [ { "family_name": "Khachaturian", "given_name": "Aroutin", "orcid": "0000-0001-8304-3302", "clpid": "Khachaturian-A" }, { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A compact, spiral Mach-Zehnder Interferometer Modulator with 9GHz 3dB-band width has been demonstrated. The spiral MZ1 structure allows for high density integration and reduces the cost by wrapping two 3mm long phase shifters in a 550\u03bcm\u00d7650\u03bcm silicon area.", "doi": "10.1109/Group4.2015.7305996", "isbn": "978-1-4799-8254-7", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2015-08", "pages": "151-152" }, { "id": "authors:krk7t-akq11", "collection": "authors", "collection_id": "krk7t-akq11", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151028-073850397", "type": "book_section", "title": "Automated Design of a 3D Printed Waveguide Surface Coupler", "book_title": "2015 IEEE Antennas and Propagation Society International Symposium", "author": [ { "family_name": "Sideris", "given_name": "Constantine", "orcid": "0000-0002-3042-4889", "clpid": "Sideris-C" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Yang", "given_name": "Chen", "clpid": "Yang-Chen" }, { "family_name": "Wu", "given_name": "Sung-Yueh", "clpid": "Wu-Sung-Yueh" }, { "family_name": "Sammoura", "given_name": "Firas", "clpid": "Sammoura-F" }, { "family_name": "Lin", "given_name": "Liwei", "clpid": "Lin-Liwei" }, { "family_name": "Alon", "given_name": "Elad", "clpid": "Alon-E" } ], "abstract": "We have implemented an automated optimization algorithm which generates de-novo EM structures under specified design objectives. We demonstrated a particular design of a surface coupling antenna which is capable of launching energy efficiently into the main mode of a plastic waveguide. A 3D printer was used to print the designed system to verify our results. The maximum available power gain of the system was measured as 0.128, implying that the coupler achieves an efficiency of at least 36% at the designed center frequency of 9.6GHz. The actual coupler efficiency is believed to be much higher because the polymer used is very lossy in this frequency range.", "doi": "10.1109/APS.2015.7304545", "isbn": "978-1-4799-7815-1", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2015-07", "pages": "318-319" }, { "id": "authors:x7r7g-2xw89", "collection": "authors", "collection_id": "x7r7g-2xw89", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150602-162920874", "type": "article", "title": "Functionalized iron oxide nanoparticles for controlling the movement of immune cells", "author": [ { "family_name": "White", "given_name": "Ethan E.", "clpid": "White-Ethan-E" }, { "family_name": "Pai", "given_name": "Alex", "clpid": "Pai-Alex" }, { "family_name": "Weng", "given_name": "Yiming", "clpid": "Weng-Yiming" }, { "family_name": "Suresh", "given_name": "Anil K.", "clpid": "Suresh-Anil-K" }, { "family_name": "Van Haute", "given_name": "Desiree", "clpid": "Van-Haute-Dseriee" }, { "family_name": "Pailevanian", "given_name": "Torkom", "clpid": "Pailevanian-Torkom" }, { "family_name": "Alizadeh", "given_name": "Darya", "orcid": "0000-0002-8470-5424", "clpid": "Alizadeh-Darya" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Badie", "given_name": "Behnam", "orcid": "0000-0001-9811-9306", "clpid": "Badie-Behnam" }, { "family_name": "Berlin", "given_name": "Jacob M.", "orcid": "0000-0001-7498-766X", "clpid": "Berlin-Jacob-M" } ], "abstract": "Immunotherapy is currently being investigated for the treatment of many diseases, including cancer. The ability to control the location of immune cells during or following activation would represent a powerful new technique for this field. Targeted magnetic delivery is emerging as a technique for controlling cell movement and localization. Here we show that this technique can be extended to microglia, the primary phagocytic immune cells in the central nervous system. The magnetized microglia were generated by loading the cells with iron oxide nanoparticles functionalized with CpG oligonucleotides, serving as a proof of principle that nanoparticles can be used to both deliver an immunostimulatory cargo to cells and to control the movement of the cells. The nanoparticle-oligonucleotide conjugates are efficiently internalized, non-toxic, and immunostimulatory. We demonstrate that the in vitro migration of the adherent, loaded microglia can be controlled by an external magnetic field and that magnetically-induced migration is non-cytotoxic. In order to capture video of this magnetically-induced migration of loaded cells, a novel 3D-printed \"cell box\" was designed to facilitate our imaging application. Analysis of cell movement velocities clearly demonstrate increased cell velocities toward the magnet. These studies represent the initial step towards our final goal of using nanoparticles to both activate immune cells and to control their trafficking within the diseased brain.", "doi": "10.1039/c3nr04421a", "pmcid": "PMC4409571", "issn": "2040-3372", "publisher": "Royal Society of Chemistry", "publication": "Nanoscale", "publication_date": "2015-05-07", "series_number": "17", "volume": "7", "issue": "17", "pages": "7780-7789" }, { "id": "authors:hw8r9-wz759", "collection": "authors", "collection_id": "hw8r9-wz759", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150602-153730543", "type": "article", "title": "Silicon Integrated 280 GHz Imaging Chipset With 4x4 SiGe Receiver Array and CMOS Source", "author": [ { "family_name": "Sengupta", "given_name": "Kaushik", "clpid": "Sengupta-K" }, { "family_name": "Seo", "given_name": "Dongjin", "clpid": "Seo-Dongjin" }, { "family_name": "Yang", "given_name": "Lita", "clpid": "Yang-Lita" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "In this paper, we report an integrated silicon-based active imaging chipset with a detector array in 0.13 \u03bcm SiGe process and a CMOS-based source array operating in the 240-290 GHz range. The chipset operates at room-temperature with no external RF or optical sources, high-resistivity silicon lenses (HRSi) or waveguides or any custom fabrication options, such as high-resistivity substrates or substrate thinning. The receiver chip consists of a 2-D array of 16 pixels, measuring 2.5 mm \u00d7 2.5 mm with integrated antennas. An electromagnetic-active circuit co-design approach is carried out to ensure high-efficiency interface with detectors operating above cut-off frequencies with good impedance matching, near-optimal noise performance, while simultaneously suppressing the dominant surface-wave modes in a lensless lossy bulk silicon substrate. The array performance is characterized in the WR-3 band between 220-320 GHz. At the designed frequency of 260 GHz, the NEP of all pixels stays between 7.9 pW/\u221a{Hz}-8.8 pW/\u221a{Hz}. The imaging chipset consists of this 2D detector array chip and a CMOS-based source array chip measuring 0.8 mm \u00d7 0.8 mm. The entire system dissipates less than 180 mW of DC power, representing a truly integrated solution.", "doi": "10.1109/TTHZ.2015.2414826", "issn": "2156-342X", "publisher": "IEEE", "publication": "IEEE Transactions on Terahertz Science and Technology", "publication_date": "2015-05", "series_number": "3", "volume": "5", "issue": "3", "pages": "427-437" }, { "id": "authors:k5ngx-5s849", "collection": "authors", "collection_id": "k5ngx-5s849", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150508-105530561", "type": "article", "title": "Dynamic Polarization Control", "author": [ { "family_name": "Bowers", "given_name": "Steven M.", "clpid": "Bowers-S-M" }, { "family_name": "Safaripour", "given_name": "Amirreza", "orcid": "0000-0001-9758-6156", "clpid": "Safaripour-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Dynamic polarization control (DPC) is the method of setting the polarization of the far-field electric field generated by a radiating antenna entirely electronically in order to maintain polarization matching with the receiving antenna regardless of its polarization or orientation in space. This work implements a fully integrated 2 \u00d7 1 phased array radiator in 32 nm CMOS SOI at 105.5 GHz with DPC. The system consists of a central locking oscillator that phase locks oscillators within the core of each antenna followed by three amplification stages with variable gain that drive the antennas. By controlling the amplitude and phase of two orthogonal polarized subparts of each multi-port antenna, various far-field polarizations can be realized. The array is capable of beam steering, controlling the polarization angle across the entire tuning range of 0\u00b0 to 180\u00b0 while maintaining axial ratios above 10 dB, and controlling the axial ratio from 2.4 dB (near circular) to 14 dB (linear) in various directions of radiation. It radiates a maximum EIRP of 7.8 dBm with a total radiated power of 0.9 mW. To the best of the authors' knowledge, this work presents the first integrated radiator with dynamically controllable polarization.", "doi": "10.1109/JSSC.2015.2403313", "issn": "0018-9200", "publisher": "IEEE", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2015-05", "series_number": "5", "volume": "50", "issue": "5", "pages": "1224-1236" }, { "id": "authors:psyge-1sa91", "collection": "authors", "collection_id": "psyge-1sa91", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151202-094628341", "type": "book_section", "title": "A 2\u00d72 Dynamic Polarization-Controlling integrated phased array", "author": [ { "family_name": "Safaripour", "given_name": "Amirreza", "orcid": "0000-0001-9758-6156", "clpid": "Safaripour-A" }, { "family_name": "Bowers", "given_name": "Steven M.", "clpid": "Bowers-S-M" }, { "family_name": "Dasgupta", "given_name": "Kaushik", "clpid": "Dasgupta-K" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Radiator arrays with Dynamic Polarization Control (DPC) and 2D beam steering enable polarization matching to the receiver antenna regardless of its polarization, orientation, and location. A fully integrated 122.9 GHz 2\u00d72 DPC multi-port driven phased array radiates all linear polarizations (0\u00b0\u2013180\u00b0 polarization angles) with axial ratios above 14 dB, and controls the axial ratio from 1.2 dB (circular) to 17.8 dB (linear) with a maximum EIRP of +12.3 dBm and 2D beam steering of up to 15\u00b0.", "doi": "10.1109/RFIC.2015.7337744", "publisher": "IEEE", "publication_date": "2015-05" }, { "id": "authors:j3fek-8xv08", "collection": "authors", "collection_id": "j3fek-8xv08", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150507-141744018", "type": "article", "title": "A mm-Wave Segmented Power Mixer", "author": [ { "family_name": "Dasgupta", "given_name": "Kaushik", "clpid": "Dasgupta-K" }, { "family_name": "Sengupta", "given_name": "Kaushik", "clpid": "Sengupta-K" }, { "family_name": "Pai", "given_name": "Alex", "clpid": "Pai-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "The segmented power-mixer array based mm-wave power generation architecture is demonstrated to be an energy-efficient technique for generating high-speed nonconstant envelope modulations. High output power levels are achieved by efficiently combining power from several power mixers using an area efficient dual-primary distributed active transformer. The segmented scheme leads to back-off efficiency improvements while simultaneously providing direct envelope modulation eliminating the need for high-speed high-efficiency supply modulators. The power mixer is implemented in a 32-nm silicon-on-insulator CMOS process and provides a peak output power of 19.1 dBm at 51 GHz with a drain efficiency of 14.2% and a peak power-added efficiency of 10.1%. High-speed constant (binary phase-shift keying, quadrature phase-shift keying), as well as nonconstant envelope modulations ( m-amplitude shift keying, quadrature amplitude modulation) show the versatility of the architecture towards spectrally efficient modulation schemes. Reliability against segment breakdown over long periods of time at 30% higher supply voltages has also been demonstrated.", "doi": "10.1109/TMTT.2015.2409094", "issn": "0018-9480", "publisher": "IEEE", "publication": "IEEE Transactions on Microwave Theory and Techniques", "publication_date": "2015-04", "series_number": "4", "volume": "63", "issue": "4", "pages": "1118-1129" }, { "id": "authors:cagkp-3n078", "collection": "authors", "collection_id": "cagkp-3n078", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150603-070801465", "type": "book_section", "title": "Hybrid Electro-Optical Solutions for High-Speed Connectivity", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Aflatouni", "given_name": "Firooz", "clpid": "Aflatouni-F" } ], "abstract": "Integrated optics can provide low-loss broadband optical delay much more readily than electronics. On the other hand, electronic integrated circuits offer unparalleled levels of signal gain and signal processing on a single die. The hybrid electro-optical solutions benefiting from\nbest of both domains can provide significant improvements overs solutions solely in one domain. In this paper, we present two examples of such hybrid electro-optical solutions.", "doi": "10.1109/OIC.2015.7115677", "publisher": "IEEE", "publication_date": "2015-04" }, { "id": "authors:7z409-crs43", "collection": "authors", "collection_id": "7z409-crs43", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150508-085919032", "type": "article", "title": "An Integrated Slot-Ring Traveling-Wave Radiator", "author": [ { "family_name": "Bowers", "given_name": "Steven M.", "clpid": "Bowers-S-M" }, { "family_name": "Safaripour", "given_name": "Amirreza", "orcid": "0000-0001-9758-6156", "clpid": "Safaripour-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Electromagnetic duality is used to design a multi-port traveling-wave slot-ring antenna with on-chip driver circuitry to create a fully integrated radiator. By creating a slot version of the multi-port driven antenna, the required exclusive use area of the antenna is significantly decreased, while still being able to perform impedance matching, power combining, and power transfer off chip through electromagnetic radiation in a single step. The driver core consists of an oscillator followed by three amplification stages. A split path inductor design was utilized to reduce the radiator's dependence on process variation in the metal stack while ensuring proper isolation between the four quadrature paths. The slot radiator has a simulated antenna efficiency of 39% and a measured single-element effective isotropic radiated power of 6.0 dBm with a total radiated power of -1.3 dBm at 134.5 GHz.", "doi": "10.1109/TMTT.2015.2405921", "issn": "0018-9480", "publisher": "IEEE", "publication": "IEEE Transactions on Microwave Theory and Techniques", "publication_date": "2015-04", "series_number": "4", "volume": "63", "issue": "4", "pages": "1154-1162" }, { "id": "authors:0m1ty-pc574", "collection": "authors", "collection_id": "0m1ty-pc574", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150623-081631466", "type": "book_section", "title": "An Adjustable Self Equalizing Photo Detector", "book_title": "Optical Fiber Communication Conference 2015", "author": [ { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Zhou", "given_name": "Andy", "clpid": "Zhou-Andy" }, { "family_name": "Aflatouni", "given_name": "Firooz", "clpid": "Aflatouni-F" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "An optically-wideband adjustable self-equalizing photo-detector (ASEPD), capable of reviving eye closure due to limited bandwidth of electro-optical components in an optical link, is presented. The ASEPD enables use of various slower electro-optical components in faster data links.", "doi": "10.1364/OFC.2015.W3A.3", "isbn": "978-1-55752-937-4", "publisher": "Optical Society of America", "publication_date": "2015-03", "pages": "Art. No. W3A.3" }, { "id": "authors:z7wdg-gpw27", "collection": "authors", "collection_id": "z7wdg-gpw27", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150403-092301542", "type": "article", "title": "Nanophotonic coherent imager", "author": [ { "family_name": "Aflatouni", "given_name": "Firooz", "clpid": "Aflatouni-F" }, { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Rekhi", "given_name": "Angad", "clpid": "Rekhi-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "An integrated silicon nanophotonic coherent imager (NCI), with a 4 \u00d7 4 array of coherent pixels is reported. In the proposed NCI, on-chip optical processing determines the intensity and depth of each point on the imaged object based on the instantaneous phase and amplitude of the optical wave incident on each pixel. The NCI operates based on a modified time-domain frequency modulated continuous wave (FMCW) ranging scheme, where concurrent time-domain measurements of both period and the zero-crossing time of each electrical output of the nanophotonic chip allows the NCI to overcome the traditional resolution limits of frequency domain detection. The detection of both intensity and relative delay enables applications such as high-resolution 3D reflective and transmissive imaging as well as index contrast imaging. We demonstrate 3D imaging with 15\u03bcm depth resolution and 50\u03bcm lateral resolution (limited by the pixel spacing) at up to 0.5-meter range. The reported NCI is also capable of detecting a 1% equivalent refractive index contrast at 1mm thickness.", "doi": "10.1364/OE.23.005117", "issn": "1094-4087", "publisher": "Optical Society of America", "publication": "Optics Express", "publication_date": "2015-02-19", "series_number": "4", "volume": "23", "issue": "4", "pages": "5117-5125" }, { "id": "authors:zsgwa-rjv65", "collection": "authors", "collection_id": "zsgwa-rjv65", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150106-084828698", "type": "article", "title": "A self-correcting quadrature voltage controlled oscillator", "author": [ { "family_name": "Arai", "given_name": "Tomoyuki", "clpid": "Arai-Tomoyuki" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A self-correcting quadrature voltage controlled oscillator (QVCO) with phase correcting loop is proposed. It comprises the QVCO core and phase correcting loop, which corrects the quadrature phase error. Two LC VCOs, buffers, and phase shifters are coupled in circular configuration to achieve IQ symmetry. This paper introduces the idea of realizing QVCO with low phase noise and accurate quadrature phase by using the phase correcting loop. The simulation results based on the 65 nm CMOS process show that the self-correcting QVCO has a phase error less than 0.5\u00b0 and 1 MHz offset phase noise of \u2212120 dBc/Hz at 3.7 GHz with 49% tuning range.", "doi": "10.1587/elex.11.20140684", "issn": "1349-2543", "publisher": "Institute of Electronics, Information and Communication Engineers", "publication": "IEICE Electronics Express", "publication_date": "2014-10-11", "series_number": "19", "volume": "11", "issue": "19", "pages": "Art. No." }, { "id": "authors:2xn66-3e849", "collection": "authors", "collection_id": "2xn66-3e849", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160105-075920380", "type": "book_section", "title": "Cell culture and cell based sensor on CMOS", "book_title": "BioCAS Proceedings", "author": [ { "family_name": "Wang", "given_name": "Hua", "clpid": "Wang-Hua" }, { "family_name": "Mahdavi", "given_name": "Alborz", "orcid": "0000-0002-8790-8112", "clpid": "Mahdavi-Alborz" }, { "family_name": "Park", "given_name": "Jongseok", "clpid": "Park-Jongseok" }, { "family_name": "Chi", "given_name": "Taiyun", "clpid": "Chi-Taiyun" }, { "family_name": "Butts", "given_name": "Jessica", "clpid": "Butts-J" }, { "family_name": "Hookway", "given_name": "Tracy A.", "clpid": "Hookway-T-A" }, { "family_name": "McDevitt", "given_name": "Todd", "clpid": "McDevitt-T" }, { "family_name": "Tirrell", "given_name": "David A.", "orcid": "0000-0003-3175-4596", "clpid": "Tirrell-D-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper focuses on CMOS biosensor technologies for cellular biosensing applications. We first present our technologies to achieve on-CMOS cell culture, maintenance, and differentiation, as the basis for CMOS cellular biosensors. Next, we introduce a CMOS frequency-shift magnetic sensor scheme which performs detections without post-processing or external biasing magnetic field. Finally, we will demonstrate a CMOS magnetic cell based sensor which achieves real-time chemical detections; such a sensor scheme can be utilized for massively paralleled high-throughput chemical screening in drug development.", "doi": "10.1109/BioCAS.2014.6981764", "isbn": "978-1-4799-2346-5", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2014-10", "pages": "468-471" }, { "id": "authors:520pc-6k916", "collection": "authors", "collection_id": "520pc-6k916", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150112-094201262", "type": "book_section", "title": "A self-equalizing photo detector", "book_title": "2014 IEEE Photonics Conference", "author": [ { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Aflatouni", "given_name": "Firooz", "clpid": "Aflatouni-F" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A self-equalizing photo-detector (SEPD) that mitigates the bandwidth limitations of electro-optical components of optical communication systems is demonstrated, enabling higher rate of data transmission, using slower components. Unlike other all-optical equalization schemes, SEPD is optically wide band, thus does not require wavelength tuning.", "doi": "10.1109/IPCon.2014.6995315", "isbn": "978-1-4577-1504-4", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2014-10", "pages": "1-2" }, { "id": "authors:ntjn6-t8275", "collection": "authors", "collection_id": "ntjn6-t8275", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151012-160140554", "type": "book_section", "title": "Dynamic Polarization Control of Integrated Radiators", "author": [ { "family_name": "Bowers", "given_name": "Steven M.", "clpid": "Bowers-S-M" }, { "family_name": "Safaripour", "given_name": "Amirreza", "orcid": "0000-0001-9758-6156", "clpid": "Safaripour-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Dynamic Polarization Control (DPC) ensures polarization matching to the receiving antenna regardless of its polarization or orientation in space. A fully integrated 105.5 GHz 2\u00d71 DPC multi-port driven radiator array with beam steering radiates linear polarization across the full polarization angle range of 0\u00b0 to 180\u00b0 maintaining axial ratios above 10 dB, and controls the axial ratio from 2.4 dB (near circular) to 13 dB (linear) in various directions of radiation and a maximum EIRP of 7.8 dBm.", "doi": "10.1109/RFIC.2014.6851723", "publisher": "IEEE", "publication_date": "2014-06" }, { "id": "authors:7g6wc-zsv55", "collection": "authors", "collection_id": "7g6wc-zsv55", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151013-083134976", "type": "book_section", "title": "An integrated traveling-wave slot radiator", "book_title": "2014 IEEE Radio Frequency Integrated Circuits Symposium", "author": [ { "family_name": "Bowers", "given_name": "Steven M.", "clpid": "Bowers-S-M" }, { "family_name": "Safaripour", "given_name": "Amirreza", "orcid": "0000-0001-9758-6156", "clpid": "Safaripour-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A traveling-wave integrated slot radiator is designed using electromagnetic duality theory based off of the ring portion of a radial multi-port driven radiator to minimize the area required exclusively for the antenna. It is designed in 32 nm SOI CMOS and driven by a buffered quadrature VCO at 4 points to create the traveling wave that radiates out of the backside of the chip. It is measured to have a maximum EIRP of 6.0 dBm at 134.5 GHz with a total radiated power of -1.7 dBm while drawing 168 mW DC power.", "doi": "10.1109/RFIC.2014.6851744", "isbn": "978-1-4799-3862-9", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2014-06", "pages": "369-372" }, { "id": "authors:2f95v-1rg12", "collection": "authors", "collection_id": "2f95v-1rg12", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151013-081934459", "type": "book_section", "title": "A 19.1dBm segmented power-mixer based multi-Gbps mm-Wave transmitter in 32nm SOI CMOS", "book_title": "2014 IEEE Radio Frequency Integrated Circuits Symposium", "author": [ { "family_name": "Dasgupta", "given_name": "Kaushik", "clpid": "Dasgupta-K" }, { "family_name": "Sengupta", "given_name": "Kaushik", "clpid": "Sengupta-K" }, { "family_name": "Pai", "given_name": "Alex", "clpid": "Pai-Alex" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A high-power, fully-integrated, mm-wave power mixer based transmitter capable of generating highspeed, complex non-constant envelope modulations is implemented in a 32nm SOI CMOS process. Segmented power generation approach is shown to be suitable for direct digital modulation as well as efficiency improvement at back-off power levels. The transmitter has a peak output power of 19.1dBm at 51GHz with a drain efficiency of 14.2% and a peak PAE of 10.1%. Measurements results show high-speed modulations for BPSK, QPSK, ASK, m-ASK and 16-QAM. Reliability of the transmitter has also been verified against worst case segmentation at 30% higher supply voltage.", "doi": "10.1109/RFIC.2014.6851737", "isbn": "978-1-4799-3862-9", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2014-06", "pages": "343-346" }, { "id": "authors:gc4xs-pb229", "collection": "authors", "collection_id": "gc4xs-pb229", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151005-152302561", "type": "book_section", "title": "Electronic Two-Dimensional Beam Steering for Integrated Optical Phased Arrays", "author": [ { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Aflatouni", "given_name": "Firooz", "clpid": "Aflatouni-F" }, { "family_name": "Rekhi", "given_name": "Angad", "clpid": "Rekhi-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper presents electrical beam steering in an integrated 4x4 2D optical phased\narray (OPA) on a silicon on insulator (SOI) process enabling fast and repeatable beam steering for\nnext generation projection, tracking, and imaging.", "doi": "10.1364/OFC.2014.M2K.7", "publisher": "Optical Society of America", "publication_date": "2014-03" }, { "id": "authors:mr99f-3zk27", "collection": "authors", "collection_id": "mr99f-3zk27", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151005-144836838", "type": "book_section", "title": "A Compact Optically Driven Travelling-Wave Radiating Source", "author": [ { "family_name": "Bowers", "given_name": "Steven M.", "clpid": "Bowers-S-M" }, { "family_name": "Abiri", "given_name": "Behrooz", "orcid": "0000-0002-3317-2752", "clpid": "Abiri-B" }, { "family_name": "Aflatouni", "given_name": "Firooz", "clpid": "Aflatouni-F" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A compact silicon-photonics optically driven mm-wave radiator uses a multi-port driven travelling-wave antenna driven by 8 silicon photodiodes with -3dB bandwidth of 25GHz to produce -9.7dBm EIRP at 180GHz.", "doi": "10.1364/OFC.2014.Tu2A.3", "publisher": "Optical Society of America", "publication_date": "2014-03" }, { "id": "authors:h5kbe-h1m60", "collection": "authors", "collection_id": "h5kbe-h1m60", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140130-085232364", "type": "article", "title": "A handheld magnetic sensing platform for antigen and nucleic acid detection", "author": [ { "family_name": "Pai", "given_name": "Alex", "clpid": "Pai-Alex" }, { "family_name": "Khachaturian", "given_name": "Aroutin", "orcid": "0000-0001-8304-3302", "clpid": "Khachaturian-A" }, { "family_name": "Chapman", "given_name": "Stephen", "clpid": "Chapman-S-A" }, { "family_name": "Hu", "given_name": "Alexander", "clpid": "Hu-Alexander" }, { "family_name": "Wang", "given_name": "Hua", "clpid": "Wang-Hua" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "The core requirements for point-of-care (POC) diagnostics necessitate low-cost, portability, easily integrated sample preparation, and quick measurement time. Frequency-shift based magnetic sensing is a measurement technique utilizing a complementary metal-oxide-semiconductor (CMOS) integrated-circuit (IC) chip for magnetic label detection. The sensing scheme leverages the low-cost manufacturing of IC chips while demonstrating the potential for multiplexing capabilities. In this article, we present modifications to this scheme for POC viability. We introduce a handheld reusable reader and a disposable open-well cartridge for the detection of nucleic acids and antigens. The diagnostic system utilizes a novel \"magnetic freezing\" technique to reduce measurement time, obviates baseline measurement before or during biological assay, and reduces sensor noise. We utilize these enhancements for the room temperature, amplification-free detection of a 31 base-pair DNA oligomer and the interferon-\u03b3 (IFN-\u03b3) protein. We have demonstrated reliable measurements down to 100 pM for the DNA assay and 1 pM for the protein.", "doi": "10.1039/C3AN01947K", "issn": "0003-2654", "publisher": "Royal Society of Chemistry", "publication": "Analyst", "publication_date": "2013-12-10", "series_number": "6", "volume": "139", "issue": "6", "pages": "1403-1411" }, { "id": "authors:rfrtc-sck96", "collection": "authors", "collection_id": "rfrtc-sck96", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140103-085626421", "type": "article", "title": "Multi-Port Driven Radiators", "author": [ { "family_name": "Bowers", "given_name": "Steven M.", "clpid": "Bowers-S-M" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Integrated multi-port driven (MPD) radiator design is presented as an approach that takes advantage of the increased design space offered by using a hybrid design of an antenna with multiple ports and its driver circuitry integrated together on a single substrate. This reduces costly losses by eliminating independent elements for power combination, output impedance matching networks, and power transfer by engineering current patterns on a chip based on the desired far field pattern. The electromagnetic radiation produced by a circularly polarized MPD antenna is calculated analytically to provide design intuition, with supporting electromagnetic simulations. A single element 160 GHz MPD antenna and the supporting driver circuitry is designed and fabricated in a 0.13 \u03bcm SiGe BiCMOS process. A tuned 8 phase ring oscillator generates the signal with each phase feeding class A power amplifiers that drive the antenna. The radiator achieves 4.6 dBm single element effective isotropically radiated power (EIRP) and total radiated power of -2.0 dBm at 161 GHz while consuming 117.5 mA DC current from a 3.3 V source. Measurements of three frequency bands at 145, 154 and 161 GHz show greater than 0 dBm EIRP for each band, demonstrating the wide band nature of the antenna.", "doi": "10.1109/TMTT.2013.2288230", "issn": "0018-9480", "publisher": "IEEE", "publication": "IEEE Transactions on Microwave Theory and Techniques", "publication_date": "2013-12", "series_number": "12", "volume": "61", "issue": "12", "pages": "4428-4441" }, { "id": "authors:kv000-0zt42", "collection": "authors", "collection_id": "kv000-0zt42", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140221-094415202", "type": "article", "title": "Design and Implementation of an Integrated Magnetic Spectrometer for Multiplexed Biosensing", "author": [ { "family_name": "Sideris", "given_name": "Constantine", "orcid": "0000-0002-3042-4889", "clpid": "Sideris-C" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Magnetic spectroscopy allows for characterization of the magnetic susceptibility of magnetic beads across a broad frequency range. This enables differentiation and quantification of multiple beads of varying types concurrently present in the active volume of a sensor's surface. A magnetic spectrometer can be used for multi-probe tagging and identification akin to multi-color fluorescent bio-sensing. We propose a new sensing methodology to perform magnetic spectroscopy and analyze various important design parameters such as SNR and gain uniformity. We present a proof-of-concept design of a fully integrated CMOS magnetic spectrometer that can detect, quantify, and characterize magnetic materials in the 1.1 GHz to 3.3 GHz frequency range, where we demonstrate magnetic multiplexing capability using a mixture of two different kinds of magnetic beads. The sensor consumes less than 2 mW of DC power within the whole frequency range, requires no external biasing magnetic fields, is implemented in a standard CMOS process, and can be powered and operated completely from a USB interface. The magnetic spectrometer not only increases the throughput and multiplexing of biosensing experiments for a given sensor area, but also can enable additional applications, such as magnetic flow cytometry and signal-collocation assays of multiple probes.", "doi": "10.1109/TBCAS.2013.2297514", "issn": "1932-4545", "publisher": "IEEE", "publication": "IEEE Transactions on Biomedical Circuits and Systems", "publication_date": "2013-12", "series_number": "6", "volume": "7", "issue": "6", "pages": "773-784" }, { "id": "authors:ywxbh-30d43", "collection": "authors", "collection_id": "ywxbh-30d43", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141212-101836648", "type": "book_section", "title": "A Handheld Magnetic Sensing Platform for Antigen And Nucleic Acid Detection", "book_title": "17th International Conference on Miniaturized Systems for Chemistry and Life Sciences", "author": [ { "family_name": "Pai", "given_name": "A.", "clpid": "Pai-A" }, { "family_name": "Khachaturian", "given_name": "A.", "orcid": "0000-0001-8304-3302", "clpid": "Khachaturian-A" }, { "family_name": "Chapman", "given_name": "S.", "clpid": "Chapman-S" }, { "family_name": "Hu", "given_name": "A.", "clpid": "Hu-A" }, { "family_name": "Wang", "given_name": "H.", "clpid": "Wang-H" }, { "family_name": "Hajimiri", "given_name": "A.", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "The core requirements for point-of-care (POC) diagnostics necessitate low-cost, high multiplexing, portability, easily integrated sample preparation, and quick measurement time [1, 2]. Frequency-shift based magnetic sensing is a measurement technique utilizing a complementary metal-oxide-semiconductor (CMOS) integrated-circuit (IC) chip for magnetic label detection. Using this technology, we have developed a complete handheld, low-power, low-cost, disposable cartridge-based diagnostic device (Fig. 1a,b) with two fully implemented assays for antigens and nucleic acids. We have demonstrated reliable measurements down to 100 pM for a 31 base-pair oligomer and 1 pM for the protein interferon-\u03b3 (IFN-\u03b3).", "isbn": "978-0-9798064-6-9", "publisher": "Caltech Library", "publication_date": "2013-10", "pages": "678-680" }, { "id": "authors:jnf07-0d064", "collection": "authors", "collection_id": "jnf07-0d064", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130621-130626802", "type": "article", "title": "Phase Noise and Fundamental Sensitivity of Oscillator-Based Reactance Sensors", "author": [ { "family_name": "Wang", "given_name": "Hua", "clpid": "Wang-Hua" }, { "family_name": "Weng", "given_name": "Ching-Chih", "clpid": "Weng-Ching-Chih" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper investigates the fundamental sensitivity of oscillator-based reactance sensors, which are widely used in numerous types of biomedical sensing applications. We first show that the intrinsic sensitivity is limited by the 1/\u0192^3 phase noise of the sensing oscillators. To achieve sensor detection sensitivity below this limit, a correlated double counting (CDC) noise suppression scheme is proposed to cancel the correlated 1/\u0192^3 phase noise in differential frequency detections. The suppression effect of the CDC scheme is thoroughly modeled. Moreover, the CDC scheme is extended to a high-order configuration, called the Interleaving-N CDC, to further improve the frequency resolution. In addition, we show that the weighting sequence on the Interleaving-N CDC data can be optimized as a digital noise filter to maximize the noise suppression. Given a sensing oscillator with any phase-noise profile, a general weighting optimization method is proposed based on the minimum variance distortion less response. As an example, an oscillator-based inductive magnetic sensor array in a 45-nm CMOS silicon-on-insulator process is implemented with the proposed CDC scheme. It achieves a noise suppression of 10.4 dB with basic CDC sheme and a frequency resolution of 0.128 parts per million for Interleaving-N CDC scheme, both with negligible power overhead. This enables inductance-change detection sensitivity of 0.41 fH for a low-Q on-chip 1.6-nH inductor with a quality factor of only 4.95.", "doi": "10.1109/TMTT.2013.2256142", "issn": "0018-9480", "publisher": "IEEE", "publication": "IEEE Transactions on Microwave Theory and Techniques", "publication_date": "2013-05", "series_number": "5", "volume": "61", "issue": "5", "pages": "2215-2229" }, { "id": "authors:evmya-cxy76", "collection": "authors", "collection_id": "evmya-cxy76", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130424-154627947", "type": "article", "title": "Integrated Self-Healing for mm-Wave Power Amplifiers", "author": [ { "family_name": "Bowers", "given_name": "Steven M.", "clpid": "Bowers-S-M" }, { "family_name": "Sengupta", "given_name": "Kaushik", "clpid": "Sengupta-K" }, { "family_name": "Dasgupta", "given_name": "Kaushik", "clpid": "Dasgupta-K" }, { "family_name": "Parker", "given_name": "Benjamin D.", "clpid": "Parker-B-D" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Self-healing as a technique for improving performance and yield of millimeter-wave power amplifiers (PAs) against process variation and transistor mismatch, load impedance mismatch, and partial and total transistor failure is described and investigated. A 28-GHz PA is presented with three types of sensors, two types of actuators, data converters, and a digital algorithm block that are all integrated on a single chip to show the validity of the technique. Two algorithms are implemented to either maximize output power or to minimize dc power for a desired output power. Measurements from 20 chips show increased RF output power up to 3 dB or reduced dc power by 50% in backoff with a 50-\u03a9 load. Self-healing with up to 4-1 voltage standing-wave ratio load impedance mismatch is verified and linear operation under nonconstant envelope modulation is shown to improve with healing. Self-healing after laser cutter induced transistor failure is verified and increases RF output power by up to 5.4 dB. The aggregate yield of the PA across several representative specifications is increased from 0% to 80% with self-healing.", "doi": "10.1109/TMTT.2013.2243750", "issn": "0018-9480", "publisher": "IEEE", "publication": "IEEE Transactions on Microwave Theory and Techniques", "publication_date": "2013-03", "series_number": "3", "volume": "61", "issue": "3", "pages": "1301-1315" }, { "id": "authors:019p2-5s532", "collection": "authors", "collection_id": "019p2-5s532", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170125-142101153", "type": "book_section", "title": "An integrated magnetic spectrometer for multiplexed biosensing", "book_title": "2013 IEEE International Solid-State Circuits Conference Digest of Technical Papers", "author": [ { "family_name": "Sideris", "given_name": "Constantine", "orcid": "0000-0002-3042-4889", "clpid": "Sideris-C" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "There is high demand for at-home and point-of-care medical diagnostic tools as a step toward fast, low-cost, personal medicine. Integrated biosensors based on magnetic labeling schemes offer higher sensitivity and lower cost due to the elimination of the optics and have emerged as a viable alternative to assays that use fluorescence for biomolecular detection. For instance, the frequency-shift sensor of [1] demonstrates a high-sensitivity example of a cost-effective magnetic particle biosensor in CMOS with no need for external magnets. Despite their cost and sensitivity advantages, magnetic biosensors reported so far suffer from a lack of multi-probe diagnostics similar to fluorescent-based approaches that use multiple colors for simultaneous single-site multiple target differentiation. This is primarily because current approaches measure changes in the magnetic susceptibility, \u03c7, either at low frequencies [2,3] or at a fixed RF frequency [1]. Consequently, these approaches do not provide a clear path for differentiating between a large number of small magnetic particles vs. a smaller number of larger size particles with similar magnetic content.", "doi": "10.1109/ISSCC.2013.6487744", "isbn": "978-1-4673-4516-3", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2013-02", "pages": "300-301" }, { "id": "authors:3wvx1-2qx29", "collection": "authors", "collection_id": "3wvx1-2qx29", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130220-142334283", "type": "article", "title": "A 0.28 THz Power-Generation and Beam-Steering Array in CMOS Based on Distributed Active Radiators", "author": [ { "family_name": "Sengupta", "given_name": "Kaushik", "clpid": "Sengupta-K" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "In this paper, we present a scalable transmitter architecture for power generation and beam-steering at THz frequencies using a centralized frequency reference, sub-harmonic signal distribution, and local phase control. The power generation and radiator core is based on a novel method called distributed active radiation, which enables high conversion efficiency from DC to radiated terahertz power above f_(max) of a technology. The design evolution of the distributed active radiator (DAR) follows from an inverse design approach, where metal surface currents at different harmonics are formulated in the silicon chip for the desired electromagnetic field profiles. Circuits and passives are then designed conjointly to synthesize and control the surface currents. The DAR consists of a self-oscillating active electromagnetic structure, comprising of two loops which sustain out-of-phase currents at the fundamental frequency and in-phase currents at the second harmonic. The fundamental signal, thus gets, spatially filtered, while the second harmonic is radiated selectively, thereby consolidating signal generation, frequency multiplication, radiation of desired harmonic and filtration of undesired harmonics simultaneously in a small silicon footprint. A two-dimensional 4\u00d74 radiating array implemented in 45 nm SOI CMOS (without high-resistivity substrate) radiates with an EIRP of +9.4 dBm at 0.28 THz and beam-steers in 2D over 80\u00b0 in both azimuth and elevation. The chip occupies 2.7 mm \u00d7 2.7 mm and dissipates 820 mW of DC power. To the best of the authors' knowledge, this is the first reported integrated beam-scanning array at THz frequencies in silicon.", "doi": "10.1109/JSSC.2012.2217831", "issn": "0018-9200", "publisher": "IEEE", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2012-12", "series_number": "12", "volume": "47", "issue": "12", "pages": "3013-3031" }, { "id": "authors:sv6n4-mhc06", "collection": "authors", "collection_id": "sv6n4-mhc06", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170207-173346762", "type": "book_section", "title": "A 7GHz wideband self-correcting quadrature VCO", "book_title": "19th IEEE International Conference on Electronics, Circuits, and Systems (ICECS 2012)", "author": [ { "family_name": "Arai", "given_name": "Tomoyuki", "clpid": "Arai-Tomoyuki" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A 4.0 to 6.6GHz self-correcting quadrature voltage controlled oscillator (QVCO) with phase compensation loop is implemented in a 65nm CMOS process. The topology couples IQ oscillation signals of two LC-VCOs, a phase shifter, and buffers with circular configuration. This paper introduces the idea to obtain low phase noise and accurate IQ phase quadrature oscillation signal, by employing phase compensation loop to correct the IQ phase error. The self-correcting QVCO achieves the IQ phase error less than a degree, and 1MHz offset phase noise -107dBc/Hz at 6.9GHz.", "doi": "10.1109/ICECS.2012.6463798", "isbn": "978-1-4673-1260-8", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2012-12", "pages": "61-64" }, { "id": "authors:1vqc6-8rn55", "collection": "authors", "collection_id": "1vqc6-8rn55", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120919-115826812", "type": "article", "title": "A magnetic cell-based sensor", "author": [ { "family_name": "Wang", "given_name": "Hua", "clpid": "Wang-Hua" }, { "family_name": "Mahdavi", "given_name": "Alborz", "orcid": "0000-0002-8790-8112", "clpid": "Mahdavi-Alborz" }, { "family_name": "Tirrell", "given_name": "David A.", "orcid": "0000-0003-3175-4596", "clpid": "Tirrell-D-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Cell-based sensing represents a new paradigm for performing direct and accurate detection of cell- or tissue-specific responses by incorporating living cells or tissues as an integral part of a sensor. Here we report a new magnetic cell-based sensing platform by combining magnetic sensors implemented in the complementary metal-oxide-semiconductor (CMOS) integrated microelectronics process with cardiac progenitor cells that are differentiated directly on-chip. We show that the pulsatile movements of on-chip cardiac progenitor cells can be monitored in a real-time manner. Our work provides a new low-cost approach to enable high-throughput screening systems as used in drug development and hand-held devices for point-of-care (PoC) biomedical diagnostic applications.", "doi": "10.1039/C2LC40392G", "issn": "1473-0197", "publisher": "Royal Society of Chemistry", "publication": "Lab on a Chip", "publication_date": "2012-08-14", "series_number": "21", "volume": "12", "issue": "21", "pages": "4465-4471" }, { "id": "authors:rx5pb-gyx60", "collection": "authors", "collection_id": "rx5pb-gyx60", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120807-104449736", "type": "book_section", "title": "On-chip sensing and actuation methods for integrated self-healing mm-wave CMOS power amplifier", "book_title": "2012 IEEE MTT-S International Microwave Symposium Digest (MTT)", "author": [ { "family_name": "Sengupta", "given_name": "Kaushik", "clpid": "Sengupta-K" }, { "family_name": "Dasgupta", "given_name": "Kaushik", "clpid": "Dasgupta-K" }, { "family_name": "Bowers", "given_name": "Steven M.", "clpid": "Bowers-S-M" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper presents various low power, compact, low insertion-loss sensors with digitized ADC output and digitally controlled actuation methods for on-chip characterization and healing of a mm-Wave power amplifier. We demonstrate low insertion loss (0.4dB) RF sensors which measure true input and output power in presence of load variations and very low-headroom (10\u201330mV) DC sensors with built-in regulators and thermal sensors as methods for measuring PA efficiency. All sensor outputs are digitized by a SAR-based ADC for communication with a central digital core. The paper also presents digitally controlled combiner tuning and PA bias actuation. The circuits are implemented in 45 nm SOI CMOS and enable full on-chip digitally controlled characterization and actuation of the PA with a power overhead of less than 6%.", "doi": "10.1109/MWSYM.2012.6259781", "isbn": "978-1-4673-1088-8", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2012-06", "pages": "1-3" }, { "id": "authors:5jy45-22574", "collection": "authors", "collection_id": "5jy45-22574", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170206-175324890", "type": "book_section", "title": "A fully-integrated self-healing power amplifier", "book_title": "2012 IEEE Radio Frequency Integrated Circuits Symposium", "author": [ { "family_name": "Bowers", "given_name": "Steven M.", "clpid": "Bowers-S-M" }, { "family_name": "Sengupta", "given_name": "Kaushik", "clpid": "Sengupta-K" }, { "family_name": "Dasgupta", "given_name": "Kaushik", "clpid": "Dasgupta-K" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A fully-integrated self-healing mm-wave power amplifier heals process variation, load mismatch, and transistor failure with on-chip sensors, actuators and an integrated digital algorithm ASIC without external calibration. Measurements of 20 chips showed increased RF power up to 3dB, or reduced DC power by 50% in backoff at 28 GHz. Healing 4-1 VSWR load mismatch for RF and DC power improvement was verified, and healing after laser induced transistor failure increased RF power up to 4.8dB.", "doi": "10.1109/RFIC.2012.6242268", "isbn": "978-1-4673-0416-0", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2012-06", "pages": "221-224" }, { "id": "authors:m9wqy-12k54", "collection": "authors", "collection_id": "m9wqy-12k54", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180817-160126772", "type": "monograph", "title": "Gone with the Wind ON_Mars (GOWON): A Wind-Driven Networked System of Mobile Sensors on Mars", "author": [ { "family_name": "Davoodi", "given_name": "Faranak", "clpid": "Davoodi-F" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Murphy", "given_name": "Neil", "clpid": "Murphy-N" }, { "family_name": "Nikzad", "given_name": "Shouleh", "clpid": "Nikzad-S" }, { "family_name": "Nesnas", "given_name": "Issa", "clpid": "Nesnas-I-A-D" }, { "family_name": "Mischna", "given_name": "Michael", "orcid": "0000-0002-8022-5319", "clpid": "Mischna-M-A" }, { "family_name": "Nesmith", "given_name": "Bill", "clpid": "Nesmith-B" } ], "abstract": "We propose a revolutionary way of studying the sur-face of Mars using a wind-driven network of mobile sensors- Gone with the Wind ON_Mars (GOWON). GOWON is envisioned to be a scalable, 100% self energy-generating and distributed system that allows in-situ mapping of a wide range of phenomena in a much larger portion of the surface of Mars compared to earlier missions. It could radically improve the possibility of finding rare phenomena like bio signatures through random wind-driven search. It could explore difficult terrains that were beyond the reach of previous missions, such as regions with very steep slopes, cluttered surfaces and/or sand dunes; GOWON is envisioned as an on going mission with a long life span. It could achieve any of NASA's scientific objectives on Mars in a cost-effective way, leaving a long lasting sensing and searching infrastructure on Mars. GOWON is a 2012 Step B invitee for NASA Innovative Advanced Concept (NIAC). It addresses the challenge area of the Mars Surface System Capabilities area. We believe the challenge to be near-term, i.e., 2018-2024.", "doi": "10.48550/arXiv.1202.3847", "publisher": "arXiv", "publication_date": "2012-02-17" }, { "id": "authors:et3qz-hv320", "collection": "authors", "collection_id": "et3qz-hv320", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170208-173325826", "type": "book_section", "title": "A versatile multi-modality serial link", "book_title": "2012 IEEE International Solid-State Circuits Conference", "author": [ { "family_name": "Tanaka", "given_name": "Yusuke", "clpid": "Tanaka-Yusuke" }, { "family_name": "Hino", "given_name": "Yasufumi", "clpid": "Hino-Yasufumi" }, { "family_name": "Okada", "given_name": "Yasuhiro", "clpid": "Okada-Yasuhiro" }, { "family_name": "Takeda", "given_name": "Takahiro", "clpid": "Takeda-Takahiro" }, { "family_name": "Ohashi", "given_name": "Sho", "clpid": "Ohashi-Sho" }, { "family_name": "Yamagishi", "given_name": "Hiroyuki", "clpid": "Yamagishi-Hiroyuki" }, { "family_name": "Kawasaki", "given_name": "Kenichi", "clpid": "Kawasaki-Kenichi" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Serial data links are often designed targeting a specific transmission medium. High-speed links using different predetermined transmission media have been demonstrated in the past [1-3]. This, however, restricts user's ability to use an integrated link interface with other transmission media once the chip is fabricated. For example, traditional transceivers for copper interconnects typically transmit baseband data, which is incompatible with a free-space wireless channel that is bandpass in nature and often uses RF carriers. A multi-modality transceiver block compatible with different transmission media is highly desirable as it offers great versatility by allowing the exact same interface circuitry to be used with different transmission media. Such a versatile interface can relax the board and system design requirements and enable the reuse of the same transceiver core with different media, reducing the time and cost overhead of re-designing and re-manufacturing.", "doi": "10.1109/ISSCC.2012.6177034", "isbn": "978-1-4673-0377-4", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2012-02", "pages": "332-334" }, { "id": "authors:ctwvk-z3z15", "collection": "authors", "collection_id": "ctwvk-z3z15", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170201-164845758", "type": "book_section", "title": "A 0.28THz 4x4 power-generation and beam-steering array", "book_title": "2012 IEEE International Solid-State Circuits Conference", "author": [ { "family_name": "Sengupta", "given_name": "Kaushik", "clpid": "Sengupta-K" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Up until recently, the terahertz frequency range (0.3 to 3THz) has been mostly addressed by high-mobility custom III-V processes, bulky and expensive nonlinear optics, or cryogenically cooled quantum cascade lasers. A low-cost room temperature alternative will enable a wide range of applications in security, defense, ultra-high-speed wireless communication, sensors, and biomedical imaging not currently accessible due to cost and size limitations. CMOS can potentially provide such a low-cost platform, but it requires novel techniques and architectures to generate, manipulate, radiate, and detect signals above transistor f_(max), which are in the sub-THz frequency region in most of today's nodes.", "doi": "10.1109/ISSCC.2012.6176999", "isbn": "978-1-4673-0377-4", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2012-02", "pages": "256-258" }, { "id": "authors:h76cn-k2p09", "collection": "authors", "collection_id": "h76cn-k2p09", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120608-092557453", "type": "article", "title": "A Wide-Swing Low-Noise Transconductance Amplifier and the Enabling of Large-Signal Handling Direct-Conversion Receivers", "author": [ { "family_name": "Keehr", "given_name": "Edward A.", "clpid": "Keehr-E-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "In this paper, the design of a wide-swing low-noise transconductance amplifier (LNTA) is presented in the context of passive mixer-based direct-conversion RF receivers, noting that the compression performance of such systems is limited by the initial voltage-to-current conversion. The proposed LNTA utilizes a stacked PMOS/NMOS common-gate configuration with its input common-mode voltage maintained by a class-AB operational transconductance amplifier (OTA). Linearization mechanisms and design procedures are explained both quantitatively and intuitively. Simulations of the LNTA at the typical corner, when ideally loaded, show an IIP3 + 32.8 dBm extrapolated at +12.5 dBm/-16.5 dBm CW blocking condition and an out-of-band 1-dB desensitization point of +22 dBm. These results are also shown to qualitatively agree with those extracted from an analytical model of the LNTA.", "doi": "10.1109/TCSI.2011.2161367", "issn": "1549-8328", "publisher": "IEEE", "publication": "IEEE Transactions on Circuits and Systems", "publication_date": "2012-01", "series_number": "1", "volume": "59", "issue": "1", "pages": "30-43" }, { "id": "authors:aw9ha-tbk88", "collection": "authors", "collection_id": "aw9ha-tbk88", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120104-113526830", "type": "article", "title": "A 12.5+12.5 Gb/s Full-Duplex Plastic Waveguide Interconnect", "author": [ { "family_name": "Fukuda", "given_name": "Satoshi", "clpid": "Fukuda-S" }, { "family_name": "Hino", "given_name": "Yasufumi", "clpid": "Hino-Y" }, { "family_name": "Ohashi", "given_name": "Sho", "clpid": "Ohashi-S" }, { "family_name": "Takeda", "given_name": "Takahiro", "clpid": "Takeda-T" }, { "family_name": "Yamagishi", "given_name": "Hiroyuki", "clpid": "Yamagishi-H" }, { "family_name": "Shinke", "given_name": "Satoru", "clpid": "Shinke-S" }, { "family_name": "Komori", "given_name": "Kenji", "clpid": "Komori-K" }, { "family_name": "Uno", "given_name": "Masahiro", "clpid": "Uno-M" }, { "family_name": "Akiyama", "given_name": "Yoshiyuki", "clpid": "Akiyama-Y" }, { "family_name": "Kawasaki", "given_name": "Kenichi", "clpid": "Kawasaki-K" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A new interconnect solution with plastic waveguide is demonstrated. The system consists of a pair of transceivers and a plastic waveguide. Millimeter wave signal is transmitted in a low-cost long piece of solid plastic dielectric acting as a waveguide. The plastic waveguide medium offers a large bandwidth for data communication using mm-wave carrier frequencies. Plastic waveguide interconnects do not require costly electrical-to-optical and optical-to-electrical conversion devices or precise alignment and offer longer transmission distances than wireless solutions due to better field confinement and lower path loss. Multiple plastic waveguides can be used in parallel and the modulated data at different frequencies can be multiplexed to increase the data rate. The demonstrated transceiver chips operate at carrier frequencies of 57 GHz and 80 GHz, and are fabricated in 40 nm low-power logic CMOS. The total area and power consumption of two transceivers are 0.41 mm^2 and 140 mW, respectively. The fabricated demonstrator with Yagi-couplers achieves full-duplex transmission of 12.5 Gb/s ASK modulated signal in each direction over the 120 mm polystyrene waveguide with no equalization. The observed bit error rates for both channels are less than 10^(-12) for a PRBS length of 2^(7)-1 at the total data rate of 25 Gb/s. This paper shows the feasibility of the plastic waveguide interconnect as a promising alternative to electrical, optical, and wireless interconnects.", "doi": "10.1109/JSSC.2011.2168870", "issn": "0018-9200", "publisher": "IEEE", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2011-12", "series_number": "12", "volume": "46", "issue": "12", "pages": "3113-3125" }, { "id": "authors:k80q0-zgr67", "collection": "authors", "collection_id": "k80q0-zgr67", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170302-130129685", "type": "book_section", "title": "A terahertz imaging receiver in \u00b5m SiGe BiCMOS technology", "book_title": "2011 International Conference on Infrared, Millimeter, and Terahertz Waves", "author": [ { "family_name": "Sengupta", "given_name": "Kaushik", "clpid": "Sengupta-K" }, { "family_name": "Seo", "given_name": "Dongjin", "clpid": "Seo-Dongjin" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper presents an integrated THz imaging receiver in bulk 0.13\u03bcm SiGe technology. The receiver, based on direct power detection, achieves a peak responsivity of 2.6MV/W and 700kV/W and a NEP of 8.7pW/\u221aHz and 32.4 pW/\u221aHz at 0.25 THz and 0.3 THz, respectively. No external silicon lens or post-processing, such as substrate thinning, was employed for improving antenna gain, efficiency and reducing power loss in substrate modes. To the best of the authors' knowledge, this is the lowest reported NEP in silicon at THz frequencies, without the use of expensive post-processing or external silicon lens.", "doi": "10.1109/irmmw-THz.2011.6105192", "isbn": "978-1-4577-0509-0", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2011-10" }, { "id": "authors:f7yn2-rkv31", "collection": "authors", "collection_id": "f7yn2-rkv31", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170209-164558334", "type": "book_section", "title": "Timing inaccuracy of clocks", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Since the beginning of time, timing accuracy has been strived for by clock designers. Although everyone has an intuitive sense of what clock accuracy and stability means, there is often an implicit comparison to some sort of assumed reference. In this talk, we will discuss the general notion of oscillator instability and evaluate the oscillator short term instability using a time-variant model which explains the evolution of the physical noise into phase noise in an oscillator. We will examine some of the design implications of such the noise evolution in the oscillator design via some practical examples.", "doi": "10.1109/CICC.2011.6055299", "publication_date": "2011-09" }, { "id": "authors:k7e5t-mfa18", "collection": "authors", "collection_id": "k7e5t-mfa18", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170223-130447610", "type": "book_section", "title": "A broadband self-healing phase synthesis scheme", "book_title": "2011 IEEE Radio Frequency Integrated Circuits Symposium", "author": [ { "family_name": "Wang", "given_name": "Hua", "clpid": "Wang-Hua" }, { "family_name": "Dasgupta", "given_name": "Kaushik", "clpid": "Dasgupta-K" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper presents a full-range broadband phase synthesis scheme with autonomous phase correction functionality. The on-chip phase measurement is achieved by a set of on-chip LO self-/inter-mixing testing sequences, which eliminates the need for auxiliary test tones. As a design example, a 2-to-6GHz quadrature phase synthesis system in a 65nm CMOS is demonstrated. The phase self-healing scheme achieves an RMS phase error of less than 0.6\u00b0 and a full 360\u00b0 interpolation within the entire band.", "doi": "10.1109/RFIC.2011.5940673", "isbn": "978-1-4244-8292-4", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2011-06" }, { "id": "authors:cz7a3-9q864", "collection": "authors", "collection_id": "cz7a3-9q864", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170222-172506615", "type": "book_section", "title": "Distributed Active Radiator arrays for efficient doubling, filtering, and beam-forming", "book_title": "2011 IEEE MTT-S International Microwave Symposium", "author": [ { "family_name": "Seo", "given_name": "Dongjin", "clpid": "Seo-Dongjin" }, { "family_name": "Sengupta", "given_name": "Kaushik", "clpid": "Sengupta-K" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Distributed Active Radiator (DAR) arrays are demonstrated as novel ways of harmonic generation, radiation, and filtration to generate power at frequencies above the cut-off frequency of a technology. As proofs-of-concept, 2\u00d71 and 2\u00d7 2 arrays of DAR with beam-forming are implemented on PCB, which are designed to oscillate at the fundamental frequency of 1.25GHz, while radiating (circularly-polarized) at the doubling frequency of 2.5GHz. The measured EIRP of 2\u00d7 1 and 2\u00d7 2 arrays are 7.46dBm and 12.96dBm, respectively, at 2.5GHz with a DC-to-radiated 2nd harmonic conversion of 0.8%. Almost 40\u00b0 of beam-steering at 2.5GHz was measured in 2D space for the 2\u00d72 array and more than 15dB suppression of the first and third harmonic compared to the desired second harmonic was measured in the radiated far-field.", "doi": "10.1109/MWSYM.2011.5972981", "isbn": "978-1-61284-757-3", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2011-06" }, { "id": "authors:fdw25-psz53", "collection": "authors", "collection_id": "fdw25-psz53", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170223-125809671", "type": "book_section", "title": "Closed-loop spurious tone reduction for self-healing frequency synthesizers", "book_title": "2011 IEEE Radio Frequency Integrated Circuits Symposium", "author": [ { "family_name": "Bohn", "given_name": "Florian", "clpid": "Bohn-F" }, { "family_name": "Dasgupta", "given_name": "Kaushik", "clpid": "Dasgupta-K" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "On-chip spurious tone detection and correction in an 8-12 GHz CMOS synthesizer is used to automatically reduce spurious output tones at different offset frequencies by up to 20dB. Using synchronous detection, sensitivity is limited by detection time only. The presented methods are generally applicable to frequency synthesizers and phased-locked loops in various applications.", "doi": "10.1109/RFIC.2011.5940704", "isbn": "978-1-4244-8292-4", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2011-06" }, { "id": "authors:bamv5-g9769", "collection": "authors", "collection_id": "bamv5-g9769", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110531-081045930", "type": "article", "title": "Successive Regeneration and Adaptive Cancellation of Higher Order Intermodulation Products in RF Receivers", "author": [ { "family_name": "Keehr", "given_name": "Edward A.", "clpid": "Keehr-E-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "In this paper, a general framework for the adaptive\nfeedforward cancellation of higher order intermodulation distortion\n(IMD) products is presented. By generating only second-order\nand principal-odd-order IMD reference products in the RF/analog\ndomain and reproducing higher order IMD reference products at\ndigital baseband, the proposed reference distortion scheme minimizes\nthe analog hardware burden on the system. Inherent in this\nprocedure is an approximation that the profile of blocking signals\ncausing IMD is dominated by one very large blocker. The limitations\nimposed by this approximation are quantitatively examined\nand shown to permit cancellation ratios of nearly the square\nof the ratio between the dominant and nondominant blocking\nsignal RMS amplitudes. An experimental receiver employing\nthe proposed technique was constructed utilizing a wide-swing\nlow-noise transconductance amplifier in order to accommodate a\nrail-to-rail (+12.4 dBm) out-of-band blocker and a -16.3-dBm\nnondominant blocker. The measured receiver out-of-band 1-dB\ndesensitization point is +12.5 dBm and the peak uncorrected\ntwo-tone third-order intermodulation intercept point (IIP3) is\n+33.5 dBm. Utilizing the proposed IMD cancellation scheme in\nthe presence of a modulated dominant blocker improves the total\ninput-referred IMD error power by over 24 dB, resulting in an\nextrapolated IIP3 metric of +43.5 dBm.", "doi": "10.1109/TMTT.2011.2123107", "issn": "0018-9480", "publisher": "IEEE", "publication": "IEEE Transactions on Microwave Theory and Techniques", "publication_date": "2011-05", "series_number": "5", "volume": "59", "issue": "5", "pages": "1379-1396" }, { "id": "authors:pynk1-h9c52", "collection": "authors", "collection_id": "pynk1-h9c52", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110324-091631996", "type": "article", "title": "Next-Generation CMOS RF Power Amplifiers", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Ten years ago, it was widely accepted conventional wisdom that wattlevel fully integrated power amplifiers (PAs) were not feasible in standard complimentary metal-oxide-semiconductor (CMOS) technology. Today millions of such devices are commercially produced and shipped every month and are used in hundreds of millions of cellular phones across the world. Such dramatic transition from being considered an impossibility even by most optimistic academics to the obvious future direction to be followed by everyone happened through a series of demonstrations based on new architectures radically different from the known PA topologies applied over more than half a century.", "doi": "10.1109/MMM.2010.939321", "issn": "1527-3342", "publisher": "IEEE", "publication": "IEEE Microwave Magazine", "publication_date": "2011-02", "series_number": "1", "volume": "12", "issue": "1", "pages": "38-45" }, { "id": "authors:z6bh9-6ma82", "collection": "authors", "collection_id": "z6bh9-6ma82", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110310-133536770", "type": "article", "title": "Solving Large-Scale Hybrid Circuit-Antenna Problems", "author": [ { "family_name": "Lavaei", "given_name": "Javad", "clpid": "Lavaei-J" }, { "family_name": "Babakhani", "given_name": "Aydin", "clpid": "Babakhani-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Doyle", "given_name": "John C.", "orcid": "0000-0002-1828-2486", "clpid": "Doyle-J-C" } ], "abstract": "Motivated by different applications in circuits, electromagnetics, and optics, this paper is concerned with the synthesis of a particular type of linear circuit, where the circuit is associated with a control unit. The objective is to design a controller for this control unit such that certain specifications on the parameters of the circuit are satisfied. It is shown that designing a control unit in the form of a switching network is an NP-complete problem that can be formulated as a rank-minimization problem. It is then proven that the underlying design problem can be cast as a semidefinite optimization if a passive network is designed instead of a switching network. Since the implementation of a passive network may need too many components, the design of a decoupled (sparse) passive network is subsequently studied. This paper introduces a tradeoff between design simplicity and implementation complexity for an important class of linear circuits. The superiority of the developed techniques is demonstrated by different simulations. In particular, for the first time in the literature, a wavelength-size passive antenna is designed, which has an excellent beamforming capability and which can concurrently make a null in at least eight directions.", "doi": "10.1109/TCSI.2010.2072010", "issn": "1549-8328", "publisher": "IEEE", "publication": "IEEE Transactions on Circuits and Systems I: Regular Papers", "publication_date": "2011-02", "series_number": "2", "volume": "58", "issue": "2", "pages": "374-387" }, { "id": "authors:cmqp4-pm554", "collection": "authors", "collection_id": "cmqp4-pm554", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170302-124725518", "type": "book_section", "title": "Distributed active radiation for THz signal generation", "book_title": "2011 IEEE International Solid-State Circuits Conference", "author": [ { "family_name": "Sengupta", "given_name": "Kaushik", "clpid": "Sengupta-K" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "In this paper, we introduce the distributed-active-radiator (DAR) structures which consolidate the signal generation, multiplication, filtering, and radiation in a single active electromagnetically coupled structure. As examples of distributed active radiators, we demonstrate 2x1 and 2x2 arrays of DAR structures radiating at 300GHz, which achieve three orders of magnitude higher total radiated power than previously reported.", "doi": "10.1109/ISSCC.2011.5746322", "isbn": "978-1-61284-302-5", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2011-02", "pages": "288-289" }, { "id": "authors:jhbs0-rrt18", "collection": "authors", "collection_id": "jhbs0-rrt18", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170308-153526291", "type": "book_section", "title": "A 12.5+12.5Gb/s full-duplex plastic waveguide interconnect", "book_title": "2011 IEEE International Solid-State Circuits Conference", "author": [ { "family_name": "Fukuda", "given_name": "Satoshi", "clpid": "Fukuda-Satoshi" }, { "family_name": "Hino", "given_name": "Yasufumi", "clpid": "Hino-Yasufumi" }, { "family_name": "Ohashi", "given_name": "Sho", "clpid": "Ohashi-Sho" }, { "family_name": "Takeda", "given_name": "Takahiro", "clpid": "Takeda-Takahiro" }, { "family_name": "Shinke", "given_name": "Satoru", "clpid": "Shinke-Satoru" }, { "family_name": "Uno", "given_name": "Masahiro", "clpid": "Uno-Masahiro" }, { "family_name": "Komori", "given_name": "Kenji", "clpid": "Komori-Kenji" }, { "family_name": "Akiyama", "given_name": "Yoshiyuki", "clpid": "Akiyama-Yoshiyuki" }, { "family_name": "Kawasaki", "given_name": "Kenichi", "clpid": "Kawasaki-Kenichi" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper presents a 12.5+12.5Gb/s full-duplex plastic waveguide interconnect solution based on millimeter-wave signal transmission. The plastic waveguide is simply a long solid piece of plastic that provides a very simple, versatile, flexible, and low-cost transmission medium that has the main advantages of optical fiber in isolation and bandwidth, without the need for costly EO and OE. The dielectric waveguide does not need to be connected electrically like the wire or aligned to micron-level accuracy like optical fibers. It can be bent and twisted without significant impact on the signal. Compared to the wireless link discussed earlier, it offers additional signal isolation and confinement. Thus, it can be extended over much longer distances due to the low attenuation in the waveguide (as opposed to free space) and multiple independent lines can be run in parallel to increase the bandwidth. In our proposed plastic waveguide link, the TXs and RXs are fully integrated in CMOS, and the waveguide couplers can be fabricated in a conventional resin package without additional cost. In our existing setting there are a transmitter and a receiver operating at different carrier frequencies on each side of the waveguide, making it possible to realize a full-duplex solution. Because of the smaller fractional bandwidth for the millimeter-wave transmission, no equalization circuit is required.", "doi": "10.1109/ISSCC.2011.5746259", "isbn": "978-1-61284-302-5", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2011-02", "pages": "150-152" }, { "id": "authors:xxaz1-zhy17", "collection": "authors", "collection_id": "xxaz1-zhy17", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141202-153053675", "type": "book_section", "title": "Design of a Frequency Shift Based CMOS Magnetic Sensor Array for Point-of-Care (PoC) Biomolecular Diagnosis Applications", "book_title": "Integrated Microsystems", "author": [ { "family_name": "Wang", "given_name": "Hua", "clpid": "Wang-Hua" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "contributor": [ { "family_name": "Iniewski", "given_name": "Krzysztof", "clpid": "Iniewski-K" } ], "abstract": "Future point-of-care (PoC) molecular-level diagnostic systems require advanced biosensors that can offer high sensitivity, ultra-portability, and a low price-tag. Targeting on-site detection of biomolecules, such as DNAs, RNAs, or proteins, this type of systems is believed to play a crucial role in a variety of emerging applications such as in-field medical diagnostics, epidemic disease control, and biohazard detection.", "isbn": "978-1-4398-3620-0", "publisher": "CRC Press", "publication_date": "2011", "pages": "109-132" }, { "id": "authors:7tsxk-ett66", "collection": "authors", "collection_id": "7tsxk-ett66", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110401-112525230", "type": "book_section", "title": "Passively Controllable Smart Antennas", "book_title": "2010 IEEE Global Telecommunications Conference", "author": [ { "family_name": "Lavaei", "given_name": "Javad", "clpid": "Lavaei-J" }, { "family_name": "Babakhani", "given_name": "Aydin", "clpid": "Babakhani-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Doyle", "given_name": "John C.", "orcid": "0000-0002-1828-2486", "clpid": "Doyle-J-C" } ], "abstract": "We recently introduced passively controllable smart (PCS) antenna systems for efficient wireless transmission, with direct applications in wireless sensor networks. A PCS antenna system is accompanied by a tunable passive controller whose adjustment at every signal transmission generates a specific radiation pattern. To reduce co-channel interference and optimize the transmitted power, this antenna can be programmed to transmit data in a desired direction in such a way that no signal is transmitted (to the far field) at pre-specified undesired directions. The controller of a PCS antenna was assumed to be centralized in our previous work, which was an impediment to its implementation. In this work, we study the design of PCS antenna systems under decentralized controllers, which are both practically implementable and cost efficient. The PCS antenna proposed here is made of one active element and its programming needs solving second-order-cone optimizations. These properties differentiate a PCS antenna from the existing smart antennas, and make it possible to implement a PCS antenna on a small-sized, low-power silicon chip.", "doi": "10.1109/GLOCOM.2010.5684358", "isbn": "978-1-4244-5638-3", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2010-12", "pages": "1-6" }, { "id": "authors:8c051-c0395", "collection": "authors", "collection_id": "8c051-c0395", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110112-123555604", "type": "article", "title": "A CMOS Broadband Power Amplifier With a Transformer-Based High-Order Output Matching Network", "author": [ { "family_name": "Wang", "given_name": "Hua", "clpid": "Wang-Hua" }, { "family_name": "Sideris", "given_name": "Constantine", "orcid": "0000-0002-3042-4889", "clpid": "Sideris-C" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A transformer-based high-order output matching network is proposed for broadband power amplifier design, which\nprovides optimum load impedance for maximum output power\nwithin a wide operating frequency range. A design methodology to convert a canonical bandpass network to the proposed matching configuration is also presented in detail. As a design example, a push-pull deep class-AB PA is implemented with a third-order output network in a standard 90 nm CMOS process. The leakage inductances of the on-chip 2:1 transformer are absorbed into the output matching to realize the third-order network with only two\ninductor footprints for area conservation. The amplifier achieves a 3 dB bandwidth from 5.2 to 13 GHz with +25.2 dBm peak P_sat and 21.6% peak PAE. The EVM for QPSK and 16-QAM signals both with 5 Msample/s are below 3.6% and 5.9% at the output 1 dB compression point. This verifies the PA's capability of amplifying a narrowband modulated signal whose center-tone can be programmed across a large frequency range. The measured BER for transmitting a truly broadband PRBS signal up to 7.5 Gb/s is less than 10^(-13) , demonstrating the PA's support for an instantaneous wide operation bandwidth.", "doi": "10.1109/JSSC.2010.2077171", "issn": "0018-9200", "publisher": "IEEE", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2010-12", "series_number": "12", "volume": "45", "issue": "12", "pages": "2709-2722" }, { "id": "authors:q501w-x0359", "collection": "authors", "collection_id": "q501w-x0359", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170313-172430381", "type": "book_section", "title": "A frequency-shift based CMOS magnetic biosensor with spatially uniform sensor transducer gain", "book_title": "IEEE Custom Integrated Circuits Conference 2010", "author": [ { "family_name": "Wang", "given_name": "Hua", "clpid": "Wang-Hua" }, { "family_name": "Sideris", "given_name": "Constantine", "orcid": "0000-0002-3042-4889", "clpid": "Sideris-C" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper presents a scalable and ultrasensitive magnetic biosensing scheme based on on-chip LC resonance frequency-shifting. The sensor transducer gain is demonstrated as being location-dependent on the sensing surface and proportional to the local polarization magnetic field strength |B|^2 generated by the sensing inductor. To improve the gain uniformity, a bowl-shape stacked coil together with floating shimming metal is proposed for the inductor design. As an implementation example, a 16-cell sensor array is designed in a 45nm CMOS process. The spatially uniform sensor gain of the array is verified by testing micron-size magnetic particles randomly placed on the sensing surface. The Correlated-Double-Counting (CDC) noise cancellation scheme is also implemented in the presented design, which achieves a noise suppression of 10.6dB with no power overhead. Overall, the presented sensor demonstrates a dynamic range of at least 85.4dB.", "doi": "10.1109/CICC.2010.5617603", "isbn": "978-1-4244-5760-1", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2010-09" }, { "id": "authors:6183c-cnh29", "collection": "authors", "collection_id": "6183c-cnh29", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110412-144235909", "type": "book_section", "title": "A Study of Near-Field Direct Antenna Modulation Systems Using Convex Optimization", "book_title": "2010 American Control Conference (ACC)", "author": [ { "family_name": "Lavaei", "given_name": "Javad", "clpid": "Lavaei-J" }, { "family_name": "Babakhani", "given_name": "Aydin", "clpid": "Babakhani-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Doyle", "given_name": "John C.", "orcid": "0000-0002-1828-2486", "clpid": "Doyle-J-C" } ], "abstract": "This paper studies the constellation diagram design\nfor a class of communication systems known as near-field\ndirect antenna modulation (NFDAM) systems. The modulation\nis carried out in a NFDAM system by means of a control\nunit that switches among a number of pre-designed passive\ncontrollers such that each controller generates a desired voltage\nsignal at the far field. To find an optimal number of signals\nthat can be transmitted and demodulated reliably in a NFDAM\nsystem, the coverage area of the signal at the far field should\nbe identified. It is shown that this coverage area is a planar\nconvex region in general and simply a circle in the case when no\nconstraints are imposed on the input impedance of the antenna\nand the voltage received at the far field. A convex optimization\nmethod is then proposed to find a polygon that is able to approximate\nthe coverage area of the signal constellation diagram\nsatisfactorily. A similar analysis is provided for the identification\nof the coverage area of the antenna input impedance, which is\nbeneficial for designing an energy-efficient NFDAM system.", "isbn": "978-1-4244-7426-4", "publisher": "IEEE", "publication_date": "2010-07", "pages": "1065-1072" }, { "id": "authors:hpgvj-krt05", "collection": "authors", "collection_id": "hpgvj-krt05", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20101011-132051958", "type": "article", "title": "Generalized Time- and Transfer-Constant Circuit Analysis", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "The generalized method of time and transfer constants\nis introduced. It can be used to determine the transfer\nfunction to the desired level of accuracy in terms of time and\ntransfer constants of first-order systems using exclusively low\nfrequency calculations. This method can be used to determine the\npoles and zeros of circuits with both inductors and capacitors.\nAn inductive proof of this generalized method is given which\nsubsumes special cases, such as methods of zero- and infinite-value\ntime constants. Several important and useful corollaries of this\nmethod are discussed and several examples are analyzed.", "doi": "10.1109/TCSI.2009.2030092", "issn": "0098-4094", "publisher": "IEEE", "publication": "IEEE Transactions on Circuits and Systems", "publication_date": "2010-06", "series_number": "6", "volume": "57", "issue": "6", "pages": "1105-1121" }, { "id": "authors:1cc7h-5aw87", "collection": "authors", "collection_id": "1cc7h-5aw87", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110413-085620030", "type": "book_section", "title": "A Compact Self-similar Power Combining Topology", "book_title": "2010 IEEE MTT-S International Microwave Symposium Digest (MTT)", "author": [ { "family_name": "Sengupta", "given_name": "Kaushik", "clpid": "Sengupta-K" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A compact, modular 16-way combiner is presented\nwhich is based on a self-similar combiner topology. The combiner\nachieves a simulated passive efficiency of 38% at 77 GHz in a\nstandard 90nm process with 1.49 \u00b5m thick AI top metal. A 77\nGHz power amplifier is built based on the combiner, combining\nthe output power of 16 stages to achieve a P_(sat) of 11.4dBm, small\nsignal gain of 9.4dB, and a 3dB bandwidth of more than 11 GHz\non a 0.7V supply, with the optimal MAG for the technology\nbeing approximately 5dB at 77 GHz. The power amplifier is\nunconditionally stable with the K factor exceeding 3.8 between\n50-90 GHz. The entire architecture is based on a modular power\nsplitting and combining network that makes the design flexible\nand scalable. To the best of the authors' knowledge, this is\nthe highest P_(sat) reported at 77 GHz in CMOS with a sub 1V\nquiescent V_(ds).", "doi": "10.1109/MWSYM.2010.5516963", "isbn": "978-1-4244-7732-6", "publisher": "IEEE", "publication_date": "2010-05", "pages": "244-247" }, { "id": "authors:s9d06-19g39", "collection": "authors", "collection_id": "s9d06-19g39", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110413-133914587", "type": "book_section", "title": "An ultrasensitive CMOS magnetic biosensor array with correlated double counting noise suppression", "book_title": "2010 IEEE MTT-S International Microwave Symposium Digest (MTT)", "author": [ { "family_name": "Wang", "given_name": "Hua", "clpid": "Wang-Hua" }, { "family_name": "Kosai", "given_name": "Shohei", "clpid": "Kosai-Shohei" }, { "family_name": "Sideris", "given_name": "Constantine", "orcid": "0000-0002-3042-4889", "clpid": "Sideris-C" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper presents a scalable and ultrasensitive\nfrequency-shift magnetic biosensing array scheme. The\ntheoretical limit of the sensor noise floor is shown to be\ndominated by the phase noise of the sensing oscillators. To\nincrease the sensitivity, a noise suppression technique, Correlated Double Counting (CDC), is proposed with no power overhead. As an implementation example, a 64-cell sensor array is designed in a standard 65nm CMOS process. The CDC scheme achieves an additional 6dB noise suppression. The magnetic sensing capability of the presented sensor is verified by detecting micron size magnetic particles with an SNR of 14.6dB for a single bead and an effective dynamic range of at least 74.5dB.", "doi": "10.1109/MWSYM.2010.5514719", "isbn": "978-1-4244-7732-6", "publisher": "IEEE", "publication_date": "2010-05", "pages": "616-619" }, { "id": "authors:rc492-bvj94", "collection": "authors", "collection_id": "rc492-bvj94", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110425-110624129", "type": "book_section", "title": "Finding globally optimum solutions in antenna optimization problems", "book_title": "2010 IEEE Antennas and Propagation Society International Symposium (APSURSI)", "author": [ { "family_name": "Babakhani", "given_name": "Aydin", "clpid": "Babakhani-A" }, { "family_name": "Lavaei", "given_name": "Javad", "clpid": "Lavaei-J" }, { "family_name": "Doyle", "given_name": "John C.", "orcid": "0000-0002-1828-2486", "clpid": "Doyle-J-C" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "During the last decade, the unprecedented increase in the affordable computational power\nhas strongly supported the development of optimization techniques for designing\nantennas. Among these techniques, genetic algorithm [1] and particle swarm optimization\n[2] could be mentioned. Most of these techniques use physical dimensions of an antenna\nas the optimization variables, and require solving Maxwell's equations (numerically) at\neach optimization step. They are usually slow, unable to handle a large number of\nvariables, and incapable of finding the globally optimum solutions. In this paper, we are\nproposing an antenna optimization technique that is orders of magnitude faster than the\nconventional schemes, can handle thousands of variables, and finds the globally optimum\nsolutions for a broad range of antenna optimization problems. In the proposed scheme,\ntermination impedances embedded on an antenna structure are used as the optimization\nvariables. This is particularly useful in designing on-chip smart antennas, where\nthousands of transistors and variable passive elements can be employed to reconfigure an\nantenna. By varying these parasitic impedances, an antenna can vary its gain, band-width,\npattern, and efficiency. The goal of this paper is to provide a systematic, numerically\nefficient approach for finding globally optimum solutions in designing smart antennas.", "doi": "10.1109/APS.2010.5561993", "isbn": "978-1-4244-4967-5", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2010", "pages": "1-4" }, { "id": "authors:q33kb-jc739", "collection": "authors", "collection_id": "q33kb-jc739", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110331-111458690", "type": "book_section", "title": "A rail-to-rail input receiver employing successive regeneration and adaptive cancellation of intermodulation products", "book_title": "Proceedings of the 2010 IEEE Radio Frequency Integrated Circuits Symposium", "author": [ { "family_name": "Keehr", "given_name": "Edward A.", "clpid": "Keehr-E-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A direct conversion receiver is demonstrated\nwhich operates in the presence of a rail-to-rail (+12.4dBm)\nout-of-band blocker and a -16.3dBm blocker, where the ICP1\nis +12.5dBm and the uncorrected extrapolated IIP3 is\n+33.5dBm. IM distortion is adaptively cancelled via\nfeedforward loops which are digitally expanded to reproduce\nhigher order nonlinear reference terms. Cancellation\nimproves input-referred total IM distortion by over 24dB,\nresulting in an extrapolated IIP3 of +45.3dBm.", "doi": "10.1109/RFIC.2010.5477407", "isbn": "978-1-4244-6241-4", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2010", "pages": "47-50" }, { "id": "authors:60fk2-g0f37", "collection": "authors", "collection_id": "60fk2-g0f37", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110310-094654711", "type": "book_section", "title": "A Frequency-Shift based CMOS Magnetic Biosensor\n with Spatially Uniform Sensor Transducer Gain", "book_title": "2010 IEEE Custom Integrated Circuits Conference", "author": [ { "family_name": "Wang", "given_name": "Hua", "clpid": "Wang-Hua" }, { "family_name": "Sideris", "given_name": "Constantine", "orcid": "0000-0002-3042-4889", "clpid": "Sideris-C" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper presents a scalable and ultrasensitive magnetic biosensing scheme based on on-chip LC resonance frequency-shifting. The sensor transducer gain is demonstrated as being location-dependent on the sensing surface and proportional to the local polarization magnetic field strength |B|^2 generated by the sensing inductor. To improve the gain uniformity, a bowl-shape stacked coil together with floating shimming metal is proposed for the inductor design. As an implementation example, a 16-cell sensor array is designed in a 45nm CMOS process. The spatially uniform sensor gain of the array is verified by testing micron-size magnetic particles randomly placed on the sensing surface. The Correlated-Double-Counting (CDC) noise cancellation scheme is also implemented in the presented design, which achieves a noise suppression of 10.6dB with no power overhead. Overall, the presented sensor demonstrates a dynamic range of at least 85.4dB.", "doi": "10.1109/CICC.2010.5617603", "isbn": "978-1-4244-5760-1", "publisher": "IEEE", "place_of_publication": "New York, NY", "publication_date": "2010", "pages": "1-4" }, { "id": "authors:bt1fs-08y55", "collection": "authors", "collection_id": "bt1fs-08y55", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190226-085922106", "type": "book_section", "title": "Solving large-scale linear circuit problems via convex optimization", "book_title": "Proceedings of the 48h IEEE Conference on Decision and Control (CDC) held jointly with 2009 28th Chinese Control Conference", "author": [ { "family_name": "Lavaei", "given_name": "Javad", "clpid": "Lavaei-J" }, { "family_name": "Babakhani", "given_name": "Aydin", "clpid": "Babakhani-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Doyle", "given_name": "John C.", "orcid": "0000-0002-1828-2486", "clpid": "Doyle-J-C" } ], "abstract": "A broad class of problems in circuits, electromagnetics, and optics can be expressed as finding some parameters of a linear system with a specific type. This paper is concerned with studying this type of circuit using the available control techniques. It is shown that the underlying problem can be recast as a rank minimization problem that is NP-hard in general. In order to circumvent this difficulty, the circuit problem is slightly modified so that the resulting optimization becomes convex. This interesting result is achieved at the cost of complicating the structure of the circuit, which introduces a trade-off between the design simplicity and the implementation complexity. When it is strictly required to solve the original circuit problem, the elegant structure of the proposed rank minimization problem allows for employing a celebrated heuristic method to solve it efficiently.", "doi": "10.1109/cdc.2009.5400690", "isbn": "978-1-4244-3872-3", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2009-12", "pages": "4977-4984" }, { "id": "authors:mqgkf-zw453", "collection": "authors", "collection_id": "mqgkf-zw453", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100126-111532019", "type": "article", "title": "An Octave-Range, Watt-Level, Fully-Integrated CMOS Switching Power Mixer Array for Linearization and Back-Off-Efficiency Improvement", "author": [ { "family_name": "Kousai", "given_name": "Shouhei", "clpid": "Kousai-S" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "The power mixer array is presented as a novel power generation approach for non-constant envelope signals. It comprises several power mixer units that are dynamically turned on and off to improve the linearity and back-off efficiency. At the circuit level, the power mixer unit can operate as a switching amplifier to achieve high peak power efficiency. Additional circuit level linearization and back-off efficiency improvement techniques are also proposed. To demonstrate the feasibility of this idea, a fully-integrated octave-range CMOS power mixer array is implemented in a 130 nm CMOS process. It is operational between 1.2 GHz and 2.4 GHz and can generate an output power of +31.3 dBm into an external 50 \u03a9 load with a PAE of 42% and a gain compression of only 0.4 dB at 1.8 GHz. It achieves a PAE of 25%, at an average output power of +26.4 dBm, and an EVM of 4.6% with a non-constant-envelope 16 QAM signal. It can also produce arbitrary signal levels down to -70 dBm of output power with the 16 QAM-modulated signal without any RF gain control circuit.", "doi": "10.1109/JSSC.2009.2032271", "issn": "0018-9200", "publisher": "IEEE", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2009-12", "series_number": "12", "volume": "44", "issue": "12", "pages": "3376-3392" }, { "id": "authors:x0xfw-gdd47", "collection": "authors", "collection_id": "x0xfw-gdd47", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090923-143136224", "type": "article", "title": "Analysis of Internally Bandlimited Multistage Cubic-Term Generators for RF Receivers", "author": [ { "family_name": "Keehr", "given_name": "Edward A.", "clpid": "Keehr-E-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Adaptive feedforward error cancellation applied to correct distortion arising from third-order nonlinearities in RF receivers requires low-noise low-power reference cubic nonidealities. Multistage cubic-term generators utilizing cascaded nonlinear operations are ideal in this regard, but the frequency response of the interstage circuitry can introduce errors into the cubing operation. In this paper, an overview of the use of cubic-term generators in receivers relative to other applications is presented. An interstage frequency response plan is presented for a receiver cubic-term generator and is shown to function for arbitrary three-signal third-order intermodulation generation. The noise of such circuits is also considered and is shown to depend on the total incoming signal power across a particular frequency band. Finally, the effects of the interstage group delay are quantified in the context of a relevant communication standard requirement.", "doi": "10.1109/TCSI.2008.2008282", "issn": "1549-8328", "publisher": "IEEE", "publication": "IEEE Transactions on Circuits and Systems I: Regular Papers", "publication_date": "2009-08", "series_number": "8", "volume": "56", "issue": "8", "pages": "1758-1771" }, { "id": "authors:s1x30-6b371", "collection": "authors", "collection_id": "s1x30-6b371", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090820-155012753", "type": "article", "title": "A Spectral-Scanning Nuclear Magnetic Resonance Imaging (MRI) Transceiver", "author": [ { "family_name": "Hassibi", "given_name": "Arjang", "clpid": "Hassibi-A" }, { "family_name": "Babakhani", "given_name": "Aydin", "clpid": "Babakhani-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "An integrated spectral-scanning nuclear magnetic resonance imaging (MRI) transceiver is implemented in a 0.12 mum SiGe BiCMOS process. The MRI transmitter and receiver circuitry is designed specifically for small-scale surface MRI diagnostics applications where creating low (below 1 T) and inhomogeneous magnetic field is more practical. The operation frequency for magnetic resonance detection and analysis is tunable from 1 kHz to 37 MHz, corresponding to 0-0.9 T magnetization for ^1H (hydrogen). The concurrent measurement bandwidth is approximately one frequency octave. The chip can also be used for conventional narrowband nuclear magnetic resonance (NMR) spectroscopy from 1 kHz up to 250 MHz. This integrated transceiver consists of both the magnetic resonance transmitter which generates the required excitation pulses for the magnetic dipole excitation, and the receiver which recovers the responses of the dipoles.", "doi": "10.1109/JSSC.2009.2020456", "issn": "0018-9200", "publisher": "IEEE", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2009-06", "series_number": "6", "volume": "44", "issue": "6", "pages": "1805-1813" }, { "id": "authors:zcpj0-06e93", "collection": "authors", "collection_id": "zcpj0-06e93", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090421-112006759", "type": "article", "title": "Near-field direct antenna modulation", "author": [ { "family_name": "Babakhani", "given_name": "Aydin", "clpid": "Babakhani-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "NFDAM systems provide a unique solution for transmitting highly secured direction-dependent data and hence preventing eavesdroppers from properly demodulating the signal. A 60-GHz proof-of-concept chip was designed and measured.", "doi": "10.1109/MMM.2008.930674", "issn": "1527-3342", "publisher": "IEEE", "publication": "IEEE Microwave Magazine", "publication_date": "2009-02", "series_number": "1", "volume": "10", "issue": "1", "pages": "36-46" }, { "id": "authors:n9xvh-5e098", "collection": "authors", "collection_id": "n9xvh-5e098", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100707-095505835", "type": "book_section", "title": "An Octave-Range Watt-Level Fully Integrated CMOS Switching Power Mixer Array for Linearization and Back-Off Efficiency Improvement", "book_title": "IEEE International Solid-State Circuits Conference - Digest of Technical Papers, 2009. ISSCC 2009.", "author": [ { "family_name": "Kousai", "given_name": "Shouhei", "clpid": "Kousai-S" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "In this paper, a wideband watt-level fully-integrated CMOS power amplifier (PA) for non-constant modulation been demonstrated. The output currents of sixteen power mixer cores are combined at their drains, where the non-constant envelope RF signal is regenerated.", "doi": "10.1109/ISSCC.2009.4977465", "isbn": "978-1-4244-3458-9", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2009-02", "pages": "376-378" }, { "id": "authors:vsjam-mz969", "collection": "authors", "collection_id": "vsjam-mz969", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170329-154122508", "type": "book_section", "title": "A compact low-noise weighted distributed amplifier in CMOS", "book_title": "2009 IEEE International Solid-State Circuits Conference - Digest of Technical Papers", "author": [ { "family_name": "Wang", "given_name": "Yu-Jiu", "clpid": "Wang-Yu-Jiu" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "The noise figure (NF) of a front-end low-noise amplifier (LNA) places a lower bound on the sensitivity of a receiver. In a conventional LNA, there is a tradeoff between the intrinsic input capacitance of the input transistors and the achievable bandwidth (BW) of the amplifier. This makes it necessary to use smaller transistors at higher gate overdrive voltages to simultaneously achieve greater BW and better NF. Unfortunately, biasing the transistor in this fashion yields a power-inefficient design. Furthermore, the need for a smaller capacitance presents a challenge to electrostatic discharge (ESD) protection of the input due to its added capacitance.", "doi": "10.1109/ISSCC.2009.4977387", "isbn": "978-1-4244-3458-9", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2009-02", "pages": "220-221" }, { "id": "authors:vym7a-b3z76", "collection": "authors", "collection_id": "vym7a-b3z76", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100615-093255945", "type": "book_section", "title": "Near-Field Direct Antenna Modulation (NFDAM) transmitter at 2.4GHz", "book_title": "Antennas and Propagation Society International Symposium, 2009", "author": [ { "family_name": "Chang", "given_name": "Arthur H.", "clpid": "Chang-A-H" }, { "family_name": "Babakhani", "given_name": "Aydin", "clpid": "Babakhani-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A near-field direct antenna modulation (NFDAM) transmitter at 2.4GHz is demonstrated on a microstrip setting. The transmitter is capable of transmitting information in a direction-dependent fashion by sending the correct signal constellation only in the desired direction while leaving the signal constellation points scrambled in undesired directions. This direction-dependent constellation scrambling nature of the NFDAM systems prevents undesired receivers to correctly demodulate the signal transmitted to a desired receiver at a specific direction.", "doi": "10.1109/APS.2009.5171550", "isbn": "978-1-4244-3646-0", "publisher": "IEEE", "publication_date": "2009", "pages": "1980-1983" }, { "id": "authors:kedc2-jtg57", "collection": "authors", "collection_id": "kedc2-jtg57", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100611-153236105", "type": "book_section", "title": "The Future of High Frequency Circuit Design", "book_title": "ESSCIRC 2009 : Proceedings of the 35th European Solid-State Circuits Conference, Athens, Greece, 14-18 September 2009", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "The cut-off wavelengths of integrated silicon transistors have\nexceeded the die sizes of the chips being fabricated with them.\nCombined with the ability to integrate billions of transistors on\nthe same die, this size-wavelength cross-over has produced a\nunique opportunity for a completely new class of holistic circuit\ndesign combining electromagnetics, device physics, circuits, and\ncommunication system theory in one place. In this paper, we discuss\nsome of these opportunities and their associated challenges\nin greater detail and provide a few of examples of how they can\nbe used in practice.", "doi": "10.1109/ESSCIRC.2009.5325926", "isbn": "978-1-4244-4355-0", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2009", "pages": "45-52" }, { "id": "authors:31z59-nkp44", "collection": "authors", "collection_id": "31z59-nkp44", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:AOKieeejscc08", "type": "article", "title": "A Fully-Integrated Quad-Band GSM/GPRS CMOS Power Amplifier", "author": [ { "family_name": "Aoki", "given_name": "Ichiro", "clpid": "Aoki-I" }, { "family_name": "Kee", "given_name": "Scott", "clpid": "Kee-S-D" }, { "family_name": "Magoon", "given_name": "Rahul", "clpid": "Magoon-R" }, { "family_name": "Aparicio", "given_name": "Roberto", "clpid": "Aparicio-R" }, { "family_name": "Bohn", "given_name": "Florian", "clpid": "Bohn-F" }, { "family_name": "Zachan", "given_name": "Jeff", "clpid": "Zachan-J" }, { "family_name": "Hatcher", "given_name": "Geoff", "clpid": "Hatcher-G" }, { "family_name": "McClymont", "given_name": "Donald", "clpid": "McClymont-D" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Concentric distributed active transformers (DAT) are used to implement a fully-integrated quad-band power amplifier (PA) in a standard 130 nm CMOS process. The DAT enables the power amplifier to integrate the input and output matching networks on the same silicon die. The PA integrates on-chip closed-loop power control and operates under supply voltages from 2.9 V to 5.5 V in a standard micro-lead-frame package. It shows no oscillations, degradation, or failures for over 2000 hours of operation with a supply of 6 V at 135\u00b0 under a VSWR of 15:1 at all phase angles and has also been tested for more than 2 million device-hours (with ongoing reliability monitoring) without a single failure under nominal operation conditions. It produces up to +35 dBm of RF power with power-added efficiency of 51%.", "doi": "10.1109/JSSC.2008.2004870", "issn": "0018-9200", "publisher": "IEEE", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2008-12", "series_number": "12", "volume": "43", "issue": "12", "pages": "2747-2758" }, { "id": "authors:v7p5x-8v926", "collection": "authors", "collection_id": "v7p5x-8v926", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:KEEieeejssc08", "type": "article", "title": "Equalization of Third-Order Intermodulation Products in Wideband Direct Conversion Receivers", "author": [ { "family_name": "Keehr", "given_name": "Edward A.", "clpid": "Keehr-E-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper reports a SAW-less direct-conversion receiver which utilizes a mixed-signal feedforward path to regenerate and adaptively cancel IM3 products, thus accomplishing system-level linearization. The receiver system performance is dominated by a custom integrated RF front end implemented in 130-nm CMOS and achieves an uncorrected out-of-band IIP3 of -7.1 dBm under the worst-case UMTS FDD Region 1 blocking specifications. Under IM3 equalization, the receiver achieves an effective IIP3 of +5.3 dBm and meets the UMTS BER sensitivity requirement with 3.7 dB of margin.", "doi": "10.1109/JSSC.2008.2005701", "issn": "0018-9200", "publisher": "IEEE", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2008-12", "series_number": "12", "volume": "43", "issue": "12", "pages": "2853-2867" }, { "id": "authors:s6wg7-cwz33", "collection": "authors", "collection_id": "s6wg7-cwz33", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:JEOieeejssc08", "type": "article", "title": "A Scalable 6-to-18 GHz Concurrent Dual-Band Quad-Beam Phased-Array Receiver in CMOS", "author": [ { "family_name": "Jeon", "given_name": "Sanggeun", "clpid": "Jeon-Sanggeun" }, { "family_name": "Wang", "given_name": "Yu-Jiu", "clpid": "Wang-Yu-Jiu" }, { "family_name": "Wang", "given_name": "Hua", "clpid": "Wang-Hua" }, { "family_name": "Bohn", "given_name": "Florian", "clpid": "Bohn-F" }, { "family_name": "Natarajan", "given_name": "Arun", "orcid": "0000-0003-3648-3844", "clpid": "Natarajan-A" }, { "family_name": "Babakhani", "given_name": "Aydin", "clpid": "Babakhani-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper reports a 6-to-18 GHz integrated phased- array receiver implemented in 130-nm CMOS. The receiver is easily scalable to build a very large-scale phased-array system. It concurrently forms four independent beams at two different frequencies from 6 to 18 GHz. The nominal conversion gain of the receiver ranges from 16 to 24 dB over the entire band while the worst-case cross-band and cross-polarization rejections are achieved 48 dB and 63 dB, respectively. Phase shifting is performed in the LO path by a digital phase rotator with the worst-case RMS phase error and amplitude variation of 0.5\u00b0 and 0.4 dB, respectively, over the entire band. A four-element phased-array receiver system is implemented based on four receiver chips. The measured array patterns agree well with the theoretical ones with a peak-to-null ratio of over 21.5 dB.", "doi": "10.1109/JSSC.2008.2004863", "issn": "0018-9200", "publisher": "IEEE", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2008-12", "series_number": "12", "volume": "43", "issue": "12", "pages": "2660-2673" }, { "id": "authors:76wk5-85j38", "collection": "authors", "collection_id": "76wk5-85j38", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BABieeejssc08", "type": "article", "title": "Transmitter Architectures Based on Near-Field Direct Antenna Modulation", "author": [ { "family_name": "Babakhani", "given_name": "Aydin", "clpid": "Babakhani-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A near-field direct antenna modulation (NFDAM) technique is introduced, where the radiated far-field signal is modulated by time-varying changes in the antenna near-field electromagnetic (EM) boundary conditions. This enables the transmitter to send data in a direction-dependent fashion producing a secure communication link. Near-field direct antenna modulation (NFDAM) can be performed by using either switches or varactors. Two fully-integrated proof-of-concept NFDAM transmitters operating at 60 GHz using switches and varactors are demonstrated in silicon proving the feasibility of this approach.", "doi": "10.1109/JSSC.2008.2004864", "issn": "0018-9200", "publisher": "IEEE", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2008-12", "series_number": "12", "volume": "43", "issue": "12", "pages": "2674-2692" }, { "id": "authors:z0462-av716", "collection": "authors", "collection_id": "z0462-av716", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170404-163909751", "type": "book_section", "title": "Digitally-Assisted Linearization of Wideband Direct Conversion Receivers", "book_title": "Proceedings of the 3rd European Microwave Integrated Circuit Conference", "author": [ { "family_name": "Keehr", "given_name": "Edward A.", "clpid": "Keehr-E-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A SAW-less direct-conversion receiver is presented which utilizes a mixed-signal feedforward path to regenerate and equalize IM3 products, thus accomplishing system-level linearization. The receiver system performance is dominated by a custom integrated front end realized in 130nm CMOS and achieves an uncorrected out-of-band IIP3 of -7.1dBm under the worst-case UMTS FDD Region 1 blocking specifications. IM3 equalization results in an effective IIP3 of +5.3dBm and reduces total input-referred error by over 23dB.", "doi": "10.1109/EMICC.2008.4772253", "isbn": "978-2-87487-007-1", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2008-10", "pages": "159-162" }, { "id": "authors:85zj7-6yq66", "collection": "authors", "collection_id": "85zj7-6yq66", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:AFSieeetcasI08", "type": "article", "title": "Ultrafast Analog Fourier Transform Using 2-D LC Lattice", "author": [ { "family_name": "Afshari", "given_name": "Ehsan", "clpid": "Afshari-E" }, { "family_name": "Bhat", "given_name": "Harish S.", "orcid": "0000-0001-7631-1831", "clpid": "Bhat-Harish-Subrahmanya" }, { "family_name": "Hajimiri", "given_name": "S. A. (Ali)", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "We describe how a 2-D rectangular lattice of inductors and capacitors can serve as an analog Fourier transform device, generating an approximate discrete Fourier transform (DFT) of an arbitrary input vector of fixed length. The lattice displays diffractive and refractive effects and mimics the combined optical effects of a thin-slit aperture and lens. Diffraction theories in optics are usually derived for 3-D media, whereas our derivations proceed in 2-D. Analytical and numerical results show agreement between lattice output and the true DFT. Potentially, this lattice can be used for an extremely low latency and high throughput analog signal processing device. The lattice can be fabricated on-chip with frequency of operation of more than 10 GHz.", "doi": "10.1109/TCSI.2008.918151", "issn": "1549-8328", "publisher": "IEEE", "publication": "IEEE Transactions on Circuits and Systems I: Regular Papers", "publication_date": "2008-09", "series_number": "8", "volume": "55", "issue": "8", "pages": "2332-2343" }, { "id": "authors:r9vds-01696", "collection": "authors", "collection_id": "r9vds-01696", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100512-105740056", "type": "book_section", "title": "Fully Integrated Frequency and Phase Generation for a 6-18GHz Tunable Multi-Band Phased-Array Receiver in CMOS", "book_title": "Radio Frequency Integrated Circuits Symposium, 2008", "author": [ { "family_name": "Bohn", "given_name": "Florian", "clpid": "Bohn-F" }, { "family_name": "Wang", "given_name": "Hua", "clpid": "Wang-Hua" }, { "family_name": "Natarajan", "given_name": "Arun S.", "clpid": "Natarajan-A-S" }, { "family_name": "Jeon", "given_name": "Sanggeun", "clpid": "Jeon-Sanggeun" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Fully integrated frequency-phase generators\nfor a 6-18GHz wide-band phased-array receiver element are\npresented that generate 5-7GHz and 9-12GHz first LO\nsignals with less than -95dBc/Hz phase noise at 100kHz\noffset. Second LO signals with digitally controllable fourquadrant phase- and amplitude spread with better than 3\u00b0\nresolution are generated and allow removal of systematic\nreference clock skew as well as accurate selection of the\nreceived signal phase. This frequency- and phase generation\nscheme was successfully demonstrated in a 6-18GHz receiver\nsystem configured as an electrical 4-element array.", "doi": "10.1109/RFIC.2008.4561472", "isbn": "978-1-4244-1808-4", "publisher": "IEEE", "publication_date": "2008-07-15", "pages": "439-442" }, { "id": "authors:ge4ns-hkc84", "collection": "authors", "collection_id": "ge4ns-hkc84", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100623-113521881", "type": "book_section", "title": "(Invited) mm-wave silicon ICs: An opportunity for holistic design", "book_title": "2008 IEEE Radio Frequency Integrated Circuits Symposium", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Millimeter-waves integrated circuits offer a unique opportunity for a holistic design approach encompassing RF, analog, and digital, as well as radiation and electromagnetics. The ability to deal with the complete system from the digital circuitry to on-chip antennas and everything in between offers unparalleled opportunities for completely new architectures and topologies, previously impossible due the traditional partitioning of various blocks in conventional design. This opens a plethora of new architectural and system level innovation within the integrated circuit platform. This paper reviews some of the challenges and opportunities for mm-wave ICs and presents several solutions to them.", "doi": "10.1109/RFIC.2008.4561453", "isbn": "978-1-4244-1808-4", "publisher": "IEEE", "publication_date": "2008-07", "pages": "357-360" }, { "id": "authors:ytbta-gfp83", "collection": "authors", "collection_id": "ytbta-gfp83", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170405-171251898", "type": "book_section", "title": "A tunable concurrent 6-to-18 GHz phased-array system in CMOS", "book_title": "2008 IEEE MTT-S International Microwave Symposium Digest", "author": [ { "family_name": "Wang", "given_name": "Hua", "clpid": "Wang-Hua" }, { "family_name": "Jeon", "given_name": "Sanggeun", "clpid": "Jeon-Sanggeun" }, { "family_name": "Wang", "given_name": "Yu-Jiu", "clpid": "Wang-Yu-Jiu" }, { "family_name": "Bohn", "given_name": "Florian", "clpid": "Bohn-F" }, { "family_name": "Natarajan", "given_name": "Arun", "orcid": "0000-0003-3648-3844", "clpid": "Natarajan-A" }, { "family_name": "Babakhani", "given_name": "Aydin", "clpid": "Babakhani-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper presents a scalable phased-array receiver system that covers a tritave bandwidth of 6-to-18 GHz implemented in a 130nm CMOS process. The single receiver element with a 10-bit phase shifting resolution achieves a maximum phase error of 2.5\u00b0 within a baseband amplitude variation of 1.5dB for an arbitrary target angle. This dense interpolation provides excellent phase error/offset calibration capability in the array. A 4-element electrical array pattern is measured at 6 GHz, 13.5 GHz and 18 GHz, showing a worst case peak-to-null ratio of 21.5dB. The EVM and phase noise improvements of the array compared with the single receiver element are also shown.", "doi": "10.1109/MWSYM.2008.4632925", "isbn": "978-1-4244-1780-3", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2008-06", "pages": "687-690" }, { "id": "authors:hxrdz-nx558", "collection": "authors", "collection_id": "hxrdz-nx558", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20171103-120941255", "type": "article", "title": "A self-sustaining ultrahigh-frequency nanoelectromechanical oscillator", "author": [ { "family_name": "Feng", "given_name": "X. L.", "clpid": "Feng-X-L" }, { "family_name": "White", "given_name": "C. J.", "clpid": "White-C-J" }, { "family_name": "Hajimiri", "given_name": "A.", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Roukes", "given_name": "M. L.", "orcid": "0000-0002-2916-6026", "clpid": "Roukes-M-L" } ], "abstract": "Sensors based on nanoelectromechanical systems vibrating at high and ultrahigh frequencies are capable of levels of performance that surpass those of larger sensors. Nanoelectromechanical devices have achieved unprecedented sensitivity in the detection of displacement, mass, force and charge. To date, these milestones have been achieved with passive devices that require external periodic or impulsive stimuli to excite them into resonance. Here, we demonstrate an autonomous and self-sustaining nanoelectromechanical oscillator that generates continuous ultrahigh-frequency signals when powered by a steady d.c. source. The frequency-determining element in the oscillator is a 428 MHz nanoelectromechanical resonator that is embedded within a tunable electrical feedback network to generate active and stable self-oscillation. Our prototype nanoelectromechanical oscillator exhibits excellent frequency stability, linewidth narrowing and low phase noise performance. Such ultrahigh-frequency oscillators provide a comparatively simple means for implementing a wide variety of practical sensing applications. They also offer intriguing opportunities for nanomechanical frequency control, timing and synchronization.", "doi": "10.1038/nnano.2008.125", "issn": "1748-3387", "publisher": "Nature Publishing Group", "publication": "Nature Nanotechnology", "publication_date": "2008-06", "series_number": "6", "volume": "3", "issue": "6", "pages": "342-346" }, { "id": "authors:9w5f8-geq18", "collection": "authors", "collection_id": "9w5f8-geq18", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170418-173743211", "type": "book_section", "title": "A Scalable 6-to-18GHz Concurrent Dual-Band Quad-Beam Phased-Array Receiver in CMOS", "book_title": "2008 IEEE International Solid-State Circuits Conference - Digest of Technical Papers", "author": [ { "family_name": "Jeon", "given_name": "Sanggeun", "clpid": "Jeon-Sanggeun" }, { "family_name": "Wang", "given_name": "Yu-Jiu", "clpid": "Wang-Yu-Jiu" }, { "family_name": "Wang", "given_name": "Hua", "clpid": "Wang-Hua" }, { "family_name": "Bohn", "given_name": "Florian", "clpid": "Bohn-F" }, { "family_name": "Natarajan", "given_name": "Arun", "orcid": "0000-0003-3648-3844", "clpid": "Natarajan-A" }, { "family_name": "Babakhani", "given_name": "Aydin", "clpid": "Babakhani-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper describes the general architecture and the signal-path behavior of a CMOS programmable phased-array receiver element that simultaneously operates at two frequencies between 6 and 18GHz (a tritave) while forming four independently controlled beams.", "doi": "10.1109/ISSCC.2008.4523119", "isbn": "978-1-4244-2010-0", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2008-02", "pages": "186-605" }, { "id": "authors:y9qeg-hr254", "collection": "authors", "collection_id": "y9qeg-hr254", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170329-155930785", "type": "book_section", "title": "A Near-Field Modulation Technique Using Antenna Reflector Switching", "book_title": "2008 IEEE International Solid-State Circuits Conference - Digest of Technical Papers", "author": [ { "family_name": "Babakhani", "given_name": "Aydin", "clpid": "Babakhani-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper presents a near-field reflector switching technique that can generate independently controlled modulated signals for sufficiently different angles of radiation. This technique can be used either to transmit different data in different directions simultaneously, or to generate the correct signal constellation only in the desired direction and scrambled ones for other angles, creating a secure communication link. This approach is also conducive to power-efficient switching PAs, even for wideband non-constant envelope modulation schemes, enabling fast and power-efficient transmitter architectures.", "doi": "10.1109/ISSCC.2008.4523120", "isbn": "978-1-4244-2010-0", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2008-02", "pages": "188-189+605" }, { "id": "authors:7v7jz-vyd97", "collection": "authors", "collection_id": "7v7jz-vyd97", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170404-173623505", "type": "book_section", "title": "Equalization of IM3 Products in Wideband Direct-Conversion Receivers", "book_title": "2008 IEEE International Solid-State Circuits Conference - Digest of Technical Papers", "author": [ { "family_name": "Keehr", "given_name": "Edward", "clpid": "Keehr-E-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "The wideband direct-conversion receiver architecture is proposed in this paper. In order to provide a quantitative design objective, the UMTS standard is targeted. The single-ended-to-differential conversion previously handled by an inter-stage SAW filter is now performed by a balun. The balun is followed by high-P2 MP mixers driven by Cherry-Hooper LO buffers. The MP BB filter is an active-RC 3 rd-order Chebyshev architecture that drives an 8b pipelined ADC with fs=50 MHz. The AP is a scaled-down version of the MP, with the primary difference being the inclusion of an IM3 generator. As scaling reduces the breakdown voltage of CMOS devices and as system integration trends demand the further elimination of off- chip components, there arises a great need to improve the linearity of RF receivers.", "doi": "10.1109/ISSCC.2008.4523128", "isbn": "978-1-4244-2010-0", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2008-02", "pages": "204-607" }, { "id": "authors:7t670-1eg88", "collection": "authors", "collection_id": "7t670-1eg88", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100917-135128884", "type": "book_section", "title": "A Spectral-Scanning Magnetic Resonance Imaging (MRI) Integrated System", "book_title": "Proceedings of the IEEE 2007 Custom Integrated Circuits Conference", "author": [ { "family_name": "Hassibi", "given_name": "Arjang", "clpid": "Hassibi-A" }, { "family_name": "Babakhani", "given_name": "Aydin", "clpid": "Babakhani-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "An integrated spectral-scanning magnetic\nresonance imaging (MRI) technique is implemented in a\n0.12\u03bcm SiGe BiCMOS process. This system is designed for\nsmall-scale MRI applications with non-uniform and low\nmagnetic fields. The system is capable of generating\ncustomized magnetic resonance (MR) excitation signals, and\nalso recovering the MR response using a coherent direct\nconversion receiver. The operation frequency is tunable from\nDC to 37MHz for wide-band MRI and up to 250MHz for\nnarrow-band MR spectroscopy.", "doi": "10.1109/CICC.2007.4405695", "isbn": "978-1-4244-0786-6", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2008-01-21", "pages": "123-126" }, { "id": "authors:0rkxr-2q152", "collection": "authors", "collection_id": "0rkxr-2q152", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100723-095124886", "type": "book_section", "title": "A 6-to-18 GHz tunable concurrent dual-band receiver front end for scalable phased arrays in 130nm CMOS", "book_title": "IEEE Radio Frequency Integrated Circuits Symposium, 2008", "author": [ { "family_name": "Wang", "given_name": "Yu-Jiu", "clpid": "Wang-Y-J" }, { "family_name": "Jeon", "given_name": "Sanggeun", "clpid": "Jeon-S" }, { "family_name": "Babakhani", "given_name": "Aydin", "clpid": "Babakhani-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper presents a study and design of tunable concurrent dual-band receiver. Different system architectures and building blocks have been compared and analyzed. A tunable concurrent dual-band receiver front end has then been fabricated and characterized. It operates across a tri-tave 6-18 GHz bandwidth with a nominal 17-25 dB conversion gain, worst-case -15 dBm IIP3, and worst-case -24.5 dBm ICP 1 dB.", "doi": "10.1109/RFIC.2008.4561450", "isbn": "978-1-4244-1808-4", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2008", "pages": "343-346" }, { "id": "authors:59h74-t7p46", "collection": "authors", "collection_id": "59h74-t7p46", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100910-112239498", "type": "book_section", "title": "mm-Wave Silicon ICs: Challenges and Opportunities", "book_title": "Proceedings of the IEEE 2007 Custom Integrated Circuits Conference", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Millimeter-waves offer promising opportunities and interesting challenges to silicon integrated circuit and system designers. These challenges go beyond standard circuit design questions and span a broader range of topics including wave propagation, antenna design, and communication channel capacity limits. It is only meaningful to evaluate the benefits and shortcoming of silicon-based mm-wave integrated circuits in this broader context. This paper reviews some of these issues and presents several solutions to them.", "doi": "10.1109/CICC.2007.4405837", "isbn": "978-1-4244-0786-6", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2007-09", "pages": "741-747" }, { "id": "authors:8vcv1-ebz23", "collection": "authors", "collection_id": "8vcv1-ebz23", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HASjap07", "type": "article", "title": "On noise processes and limits of performance in biosensors", "author": [ { "family_name": "Hassibi", "given_name": "Arjang", "clpid": "Hassibi-A" }, { "family_name": "Vikalo", "given_name": "Haris", "clpid": "Vikalo-H" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "In this paper, we present a comprehensive stochastic model describing the measurement uncertainty, output signal, and limits of detection of affinity-based biosensors. The biochemical events within the biosensor platform are modeled by a Markov stochastic process, describing both the probabilistic mass transfer and the interactions of analytes with the capturing probes. To generalize this model and incorporate the detection process, we add noisy signal transduction and amplification stages to the Markov model. Using this approach, we are able to evaluate not only the output signal and the statistics of its fluctuation but also the noise contributions of each stage within the biosensor platform. Furthermore, we apply our formulations to define the signal-to-noise ratio, noise figure, and detection dynamic range of affinity-based biosensors. Motivated by the platforms encountered in practice, we construct the noise model of a number of widely used systems. The results of this study show that our formulations predict the behavioral characteristics of affinity-based biosensors which indicate the validity of the model.", "doi": "10.1063/1.2748624", "issn": "0021-8979", "publisher": "Journal of Applied Physics", "publication": "Journal of Applied Physics", "publication_date": "2007-07-01", "series_number": "1", "volume": "102", "issue": "1", "pages": "Art. No. 014909" }, { "id": "authors:50d8c-p4g50", "collection": "authors", "collection_id": "50d8c-p4g50", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170419-140611625", "type": "book_section", "title": "mm-wave phased arrays in silicon with integrated antennas", "book_title": "2007 IEEE Antennas and Propagation International Symposium", "author": [ { "family_name": "Babakhani", "given_name": "A.", "clpid": "Babakhani-A" }, { "family_name": "Rutledge", "given_name": "D. B.", "clpid": "Rutledge-D-B" }, { "family_name": "Hajimiri", "given_name": "A.", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This work demonstrates W-band integrated dipole antennas and a four channel phased transceiver implemented in IBM 130 nm silicon germanium BiCMOS process. The chip includes the complete receiver, transmitter, signal generation blocks, phase shifters, and on-chip dipole antennas. A hemispherical silicon lens with diameter of about one inch is also used to remove the substrate modes. Measurement results show a maximum antenna gain of about +8 dB.", "doi": "10.1109/APS.2007.4396510", "isbn": "978-1-4244-0877-1", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2007-06", "pages": "4369-4372" }, { "id": "authors:f0x0c-byt70", "collection": "authors", "collection_id": "f0x0c-byt70", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:MANieeejssc07", "type": "article", "title": "A Breakdown Voltage Multiplier for High Voltage Swing Drivers", "author": [ { "family_name": "Mandegaran", "given_name": "Sam", "clpid": "Mandegaran-S" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A novel breakdown voltage (BV) multiplier is introduced that makes it possible to generate high output voltage swings using transistors with low breakdown voltages. The timing analysis of the stage is used to optimize its dynamic response. A 10 Gb/s optical modulator driver with a differential output voltage swing of 8 V on a 50 \u03a9 load was implemented in a SiGe BiCMOS process. It uses the BV-Doubler topology to achieve output swings twice the collector\u2013emitter breakdown voltage without stressing any single transistor.", "doi": "10.1109/JSSC.2006.889390", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2007-02-01", "series_number": "2", "volume": "42", "issue": "2", "pages": "302-312" }, { "id": "authors:2db4p-t4m59", "collection": "authors", "collection_id": "2db4p-t4m59", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20101029-143100560", "type": "book_section", "title": "A Wideband CMOS Linear Digital Phase Rotator", "book_title": "Proceedings of the IEEE 2007 Custom Integrated Circuits Conference", "author": [ { "family_name": "Wang", "given_name": "Hua", "clpid": "Wang-Hua" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper presents a 10-bit wideband Cartesian phase\nrotator with a novel linear digital VGA implemented in a 0.13um\nCMOS process. The VGA topology is robust to device modeling\nuncertainties and PVT variations. The system provides 7.8dB\nvoltage gain with -3dB bandwidth of 7.6GHz. A maximum phase\nerror of 2\u00ba has been achieved for a phase shifting range of\n360\u00ba with 32 phase steps of 11.25\u00ba. The capability to\ncompensate for mismatched quadrature inputs is also\ndemonstrated.", "doi": "10.1109/CICC.2007.4405821", "isbn": "978-1-4244-0786-6", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2007", "pages": "671-674" }, { "id": "authors:hm5yw-sg109", "collection": "authors", "collection_id": "hm5yw-sg109", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ROKapl06", "type": "article", "title": "Brownian noise in radiation-pressure-driven micromechanical oscillators", "author": [ { "family_name": "Rokhsari", "given_name": "Hossein", "clpid": "Rokhsari-H" }, { "family_name": "Hossein-Zadeh", "given_name": "Mani", "clpid": "Hossein-Zadeh-M" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Vahala", "given_name": "Kerry", "orcid": "0000-0003-1783-1380", "clpid": "Vahala-K-J" } ], "abstract": "The authors demonstrate Brownian-noise-limited operation of an optomechanical oscillator, wherein mechanical oscillations of a silica optical microcavity are sustained by means of radiation pressure. Using phase noise measurement above threshold, it has been shown that the short-term linewidth of mechanical oscillations is fundamentally broadened, limited by thermal equipartition of energy.", "doi": "10.1063/1.2424276", "issn": "0003-6951", "publisher": "Applied Physics Letters", "publication": "Applied Physics Letters", "publication_date": "2006-12-25", "series_number": "26", "volume": "89", "issue": "26", "pages": "Art. No. 261109" }, { "id": "authors:97vsz-v9y28", "collection": "authors", "collection_id": "97vsz-v9y28", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BABieeejssc06", "type": "article", "title": "A 77-GHz Phased-Array Transceiver With On-Chip Antennas in Silicon: Receiver and Antennas", "author": [ { "family_name": "Babakhani", "given_name": "Aydin", "clpid": "Babakhani-A" }, { "family_name": "Guan", "given_name": "Xiang", "clpid": "Guan-X" }, { "family_name": "Komijani", "given_name": "Abbas", "clpid": "Komijani-A" }, { "family_name": "Natarajan", "given_name": "Arun", "orcid": "0000-0003-3648-3844", "clpid": "Natarajan-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "In this paper, we present the receiver and the on-chip antenna sections of a fully integrated 77-GHz four-element phased-array transceiver with on-chip antennas in silicon. The receiver section of the chip includes the complete down-conversion path comprising low-noise amplifier (LNA), frequency synthesizer, phase rotators, combining amplifiers, and on-chip dipole antennas. The signal combining is performed using a novel distributed active combining amplifier at an IF of 26 GHz. In the LO path, the output of the 52-GHz VCO is routed to different elements and can be phase shifted locally by the phase rotators. A silicon lens on the backside is used to reduce the loss due to the surface-wave power of the silicon substrate. Our measurements show a single-element LNA gain of 23 dB and a noise figure of 6.0 dB. Each of the four receive paths has a gain of 37 dB and a noise figure of 8.0 dB. Each on-chip antenna has a gain of +2 dBi.", "doi": "10.1109/JSSC.2006.884811", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2006-12-01", "series_number": "12", "volume": "41", "issue": "12", "pages": "2795-2806" }, { "id": "authors:3as2h-k1z76", "collection": "authors", "collection_id": "3as2h-k1z76", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:NATieeejssc06", "type": "article", "title": "A 77-GHz Phased-Array Transceiver With On-Chip Antennas in Silicon: Transmitter and Local LO-Path Phase Shifting", "author": [ { "family_name": "Natarajan", "given_name": "Arun", "orcid": "0000-0003-3648-3844", "clpid": "Natarajan-A" }, { "family_name": "Komijani", "given_name": "Abbas", "clpid": "Komijani-A" }, { "family_name": "Guan", "given_name": "Xiang", "clpid": "Guan-X" }, { "family_name": "Babakhani", "given_name": "Aydin", "clpid": "Babakhani-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Integration of mm-wave multiple-antenna systems on silicon-based processes enables complex, low-cost systems for high-frequency communication and sensing applications. In this paper, the transmitter and LO-path phase-shifting sections of the first fully integrated 77-GHz phased-array transceiver are presented. The SiGe transceiver utilizes a local LO-path phase-shifting architecture to achieve beam steering and includes four transmit and receive elements, along with the LO frequency generation and distribution circuitry. The local LO-path phase-shifting scheme enables a robust distribution network that scales well with increasing frequency and/or number of elements while providing high-resolution phase shifts. Each element of the heterodyne transmitter generates +12.5 dBm of output power at 77 GHz with a bandwidth of 2.5 GHz leading to a 4-element effective isotropic radiated power (EIRP) of 24.5 dBm. Each on-chip PA has a maximum saturated power of +17.5 dBm at 77 GHz. The phased-array performance is measured using an internal test option and achieves 12-dB peak-to-null ratio with two transmit and receive elements active.", "doi": "10.1109/JSSC.2006.884817", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2006-12-01", "series_number": "12", "volume": "41", "issue": "12", "pages": "2807-2819" }, { "id": "authors:0aw3h-0yx83", "collection": "authors", "collection_id": "0aw3h-0yx83", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BUCieeemtt06", "type": "article", "title": "An Integrated Subharmonic Coupled-Oscillator Scheme for a 60-GHz Phased-Array Transmitter", "author": [ { "family_name": "Buckwalter", "given_name": "James F.", "clpid": "Buckwalter-J-F" }, { "family_name": "Babakhani", "given_name": "Aydin", "clpid": "Babakhani-A" }, { "family_name": "Komijani", "given_name": "Abbas", "clpid": "Komijani-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper describes the design of an integrated coupled-oscillator array in SiGe for millimeter-wave applications. The design focuses on a scalable radio architecture where multiple dies are tiled to form larger arrays. A 2 \u00d7 2 oscillator array for a 60-GHz transmitter is fabricated with integrated power amplifiers and on-chip antennas. To lock between multiple dies, an injection-locking scheme appropriate for wire-bond interconnects is described. The 2 \u00d7 2 array demonstrates a 200\u2013MHz locking range and 1 \u00d7 4 array formed by two adjacent chips has a 60-MHz locking range. The phase noise of the coupled oscillators is below 100 dBc/Hz at a 1-MHz offset when locked to an external reference. To the best of the authors' knowledge, this is the highest frequency demonstration of coupled oscillators fabricated in a conventional silicon integrated-circuit process.", "doi": "10.1109/TMTT.2006.885581", "issn": "0018-9480", "publisher": "IEEE", "publication": "IEEE Transactions on Microwave Theory and Techniques", "publication_date": "2006-12", "series_number": "12, Pa", "volume": "54", "issue": "12, Pa", "pages": "4271-4280" }, { "id": "authors:r8yn2-dwb31", "collection": "authors", "collection_id": "r8yn2-dwb31", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:KOMieeejssc06", "type": "article", "title": "A Wideband 77-GHz, 17.5-dBm Fully Integrated Power Amplifier in Silicon", "author": [ { "family_name": "Komijani", "given_name": "Abbas", "clpid": "Komijani-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A 77-GHz, +17.5 dBm power amplifier (PA) with fully integrated 50-\u03a9 input and output matching and fabricated in a 0.12-\u00b5m SiGe BiCMOS process is presented. The PA achieves a peak power gain of 17 dB and a maximum single-ended output power of 17.5 dBm with 12.8% of power-added efficiency (PAE). It has a 3-dB bandwidth of 15 GHz and draws 165 mA from a 1.8-V supply. Conductor-backed coplanar waveguide (CBCPW) is used as the transmission line structure resulting in large isolation between adjacent lines, enabling integration of the PA in an area of 0.6 mm^2. By using a separate image-rejection filter incorporated before the PA, the rejection at IF frequency of 25 GHz is improved by 35 dB, helping to keep the PA design wideband.", "doi": "10.1109/JSSC.2006.877258", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2006-08-01", "series_number": "8", "volume": "41", "issue": "8", "pages": "1749-1756" }, { "id": "authors:mr37j-f1w31", "collection": "authors", "collection_id": "mr37j-f1w31", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HOSpra06", "type": "article", "title": "Characterization of a radiation-pressure-driven micromechanical oscillator", "author": [ { "family_name": "Hossein-Zadeh", "given_name": "Mani", "clpid": "Hossein-Zadeh-M" }, { "family_name": "Rokhsari", "given_name": "Hossein", "clpid": "Rokhsari-H" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Vahala", "given_name": "Kerry J.", "orcid": "0000-0003-1783-1380", "clpid": "Vahala-K-J" } ], "abstract": "We present for the first time a detailed experimental study of the oscillation frequency, linewidth, RF spectrum and the phase noise of a radiation-pressure-driven micromechanical oscillator in a microtoroid geometry. Through this study we identify the critical parameters for optimal operation of this device and derive key expressions for tailoring the desired characteristics. The outcome of this study paves the ground for exploiting this unique phenomenon in photonic systems as well as fundamental studies in macroscopic quantum mechanics.", "doi": "10.1103/PhysRevA.74.023813", "issn": "1050-2947", "publisher": "Physical Review A", "publication": "Physical Review A", "publication_date": "2006-08-01", "series_number": "2", "volume": "74", "issue": "2", "pages": "Art. No. 023813" }, { "id": "authors:1g0w3-bf512", "collection": "authors", "collection_id": "1g0w3-bf512", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BUCieeejssc06c", "type": "article", "title": "Phase and amplitude pre-emphasis techniques for low-power serial links", "author": [ { "family_name": "Buckwalter", "given_name": "James F.", "clpid": "Buckwalter-J-F" }, { "family_name": "Meghelli", "given_name": "Mounir", "clpid": "Meghelli-M" }, { "family_name": "Friedman", "given_name": "Daniel J.", "clpid": "Friedman-D-J" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A novel approach to equalization of high-speed serial links combines both amplitude pre-emphasis to correct for intersymbol interference and phase pre-emphasis to compensate for deterministic jitter, in particular, data-dependent jitter. Phase pre-emphasis augments the performance of low power transmitters in bandwidth-limited channels. The transmitter circuit is implemented in a 90-nm bulk CMOS process and reduces power consumption by pushing CMOS static logic to the output stage, a 4:1 output multiplexer. The received signal jitter over a cable is reduced from 16.15 ps to 10.29 ps with only phase pre-emphasis at the transmitter. The jitter is reduced by 3.6 ps over an FR-4 backplane interconnect. A transmitter without phase pre-emphasis consumes 18 mW of power at 6Gb/s and 600mVpp output swing, a power budget of 3mW/Gb/s, while a transmitter with phase pre-emphasis consumes 24mW, a budget of 4 mW/Gb/s.", "doi": "10.1109/JSSC.2006.874270", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2006-06-01", "series_number": "6", "volume": "41", "issue": "6", "pages": "1391-1399" }, { "id": "authors:rf9yj-9e969", "collection": "authors", "collection_id": "rf9yj-9e969", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110119-112821542", "type": "book_section", "title": "Quadrature Subharmonic Coupled Oscillators for a 60GHz SiGe Scalable Phased Array", "book_title": "IEEE MTT-S International Microwave Symposium Digest 2006", "author": [ { "family_name": "Buckwalter", "given_name": "James F.", "clpid": "Buckwalter-J-F" }, { "family_name": "Babakhani", "given_name": "Aydin", "clpid": "Babakhani-A" }, { "family_name": "Komijani", "given_name": "Abbas", "clpid": "Komijani-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper describes an integrated coupled oscillator array in SiGe for millimeter wave applications. The design focuses on scalable radio architectures where multiple dies are tiled to form larger arrays. A 2 x 2 oscillator array for a 60GHz transmitter is designed with integrated power amplifiers and antennas. The 2 x 2 array demonstrates a 200MHz locking range and 1 x 4 array formed by two adjacent chips has a 60MHz locking range. The phase noise of the array is below -110dBc/Hz at a 1MHz offset.", "doi": "10.1109/MWSYM.2006.249799", "isbn": "978-0-7803-9541-1", "publisher": "IEEE", "publication_date": "2006-06", "pages": "822-825" }, { "id": "authors:7ee3s-sf944", "collection": "authors", "collection_id": "7ee3s-sf944", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:AFSjap06", "type": "article", "title": "Extremely wideband signal shaping using one- and two-dimensional nonuniform nonlinear transmission lines", "author": [ { "family_name": "Afshari", "given_name": "E.", "clpid": "Afshari-E" }, { "family_name": "Bhat", "given_name": "H. S.", "clpid": "Bhat-H-S" }, { "family_name": "Hajimiri", "given_name": "A.", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Marsden", "given_name": "J. E.", "clpid": "Marsden-J-E" } ], "abstract": "We propose a class of electrical circuits for extremely wideband (EWB) signal shaping. A one-dimensional, nonlinear, nonuniform transmission line is proposed for narrow pulse generation. A two-dimensional transmission lattice is proposed for EWB signal combining. Model equations for the circuits are derived. Theoretical and numerical solutions of the model equations are presented, showing that the circuits can be used for the desired application. The procedure by which the circuits are designed exemplifies a modern, mathematical design methodology for EWB circuits.", "doi": "10.1063/1.2174126", "issn": "0021-8979", "publisher": "Journal of Applied Physics", "publication": "Journal of Applied Physics", "publication_date": "2006-03-01", "series_number": "5", "volume": "99", "issue": "5", "pages": "Art. No. 054901" }, { "id": "authors:jq1pe-gvw12", "collection": "authors", "collection_id": "jq1pe-gvw12", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BUCieeejssc06a", "type": "article", "title": "Analysis and equalization of data-dependent jitter", "author": [ { "family_name": "Buckwalter", "given_name": "James F.", "clpid": "Buckwalter-J-F" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Data-dependent jitter limits the bit-error rate (BER) performance of broadband communication systems and aggravates synchronization in phase- and delay-locked loops used for data recovery. A method for calculating the data-dependent jitter in broadband systems from the pulse response is discussed. The impact of jitter on conventional clock and data recovery circuits is studied in the time and frequency domain. The deterministic nature of data-dependent jitter suggests equalization techniques suitable for high-speed circuits. Two equalizer circuit implementations are presented. The first is a SiGe clock and data recovery circuit modified to incorporate a deterministic jitter equalizer. This circuit demonstrates the reduction of jitter in the recovered clock. The second circuit is a MOS implementation of a jitter equalizer with independent control of the rising and falling edge timing. This equalizer demonstrates improvement of the timing margins that achieve 10/sup -12/ BER from 30 to 52 ps at 10 Gb/s.", "doi": "10.1109/JSSC.2005.864119", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2006-03-01", "series_number": "3", "volume": "41", "issue": "3", "pages": "607-620" }, { "id": "authors:994c0-rvk50", "collection": "authors", "collection_id": "994c0-rvk50", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BUCieeejssc06b", "type": "article", "title": "Cancellation of crosstalk-induced jitter", "author": [ { "family_name": "Buckwalter", "given_name": "James F.", "clpid": "Buckwalter-J-F" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A novel jitter equalization circuit is presented that addresses crosstalk-induced jitter in high-speed serial links. A simple model of electromagnetic coupling demonstrates the generation of crosstalk-induced jitter. The analysis highlights unique aspects of crosstalk-induced jitter that differ from far-end crosstalk. The model is used to predict the crosstalk-induced jitter in 2-PAM and 4-PAM, which is compared to measurement. Furthermore, the model suggests an equalizer that compensates for the data-induced electromagnetic coupling between adjacent links and is suitable for pre- or post-emphasis schemes. The circuits are implemented using 130-nm MOSFETs and operate at 5-10 Gb/s. The results demonstrate reduced deterministic jitter and lower bit-error rate (BER). At 10 Gb/s, the crosstalk-induced jitter equalizer opens the eye at 10^sup-12 BER from 17 to 45 ps and lowers the rms jitter from 8.7 to 6.3 ps.", "doi": "10.1109/JSSC.2005.864113", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2006-03-01", "series_number": "3", "volume": "41", "issue": "3", "pages": "621-632" }, { "id": "authors:7309e-jts86", "collection": "authors", "collection_id": "7309e-jts86", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HAJcsic05", "type": "book_section", "title": "Fully integrated millimeter-wave CMOS phased arrays", "book_title": "Compound Semiconductor Integrated Circuit Symposium, 2005 (CSIC '05)", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A decade ago, RF CMOS, even at low gigahertz frequencies, was considered an oxymoron by all but the most ambitious and\noptimistic. Today, it is a dominating force in most commercial wireless applications (e.g., cellular, WLAN, GPS, BlueTooth, etc.) and has proliferated into areas such as watt level power amplifiers (PA) [1] that have been the undisputed realm of compound semiconductors. \n\nThis seemingly ubiquitous embracement of silicon and particularly CMOS is no accident. It stems from the reliable nature of silicon process technologies that make it possible to integrated hundreds of millions of transistors on a single chip without a single device failure, as evident in today's microprocessors. Applied to microwave and millimeter wave applications, silicon opens the door for a plethora of new topologies, architectures, and applications. This rapid adoption of silicon is further facilitated by one's ability to integrate a great deal of in situ digital signal processing and calibration [2]. \n\nIntegration of high-frequency phased-array systems in silicon (e.g., CMOS) promises a future of low-cost radar and gigabit-per-second wireless communication networks. In communication applications, phased array provides an improved signal-to-noise ratio via formation of a beam and reduced interference generation for other users. The practically unlimited number of active and passive devices available on a silicon chip and their extremely tight control and excellent repeatability enable new architectures (e.g., [3]) that are not practical in compound semiconductor module-based approaches. \n\nThe feasibility of such approaches can be seen through the discussion of an integrated 24GHz 4-element phased-array transmitter in 0.18\u03bcm CMOS [2], capable of beam forming and rapid beam steering for radar applications. On-chip power amplifiers (PA), with integrated 50\u03a9 output matching, make this a fully-integrated transmitter. This CMOS transmitter and the 8-element phased-array SiGe receiver in [5], demonstrate the feasibility of 24GHz phased-array systems in silicon-based processes.", "doi": "10.1109/CSICS.2005.1531752", "isbn": "0-7803-9250-7", "publisher": "IEEE", "place_of_publication": "Los Alamitos, CA", "publication_date": "2006-01-30", "pages": "45-48" }, { "id": "authors:njykm-a7s82", "collection": "authors", "collection_id": "njykm-a7s82", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100423-142111516", "type": "book_section", "title": "Characterization of a Radiation-Pressure-Driven Micromechanical Oscillator", "book_title": "Proceedings of the 2006 IEEE International Frequency Control Symposium and Exposition", "author": [ { "family_name": "Hossein-Zadeh", "given_name": "Mani", "clpid": "Hossein-Zadeh-M" }, { "family_name": "Rokhsari", "given_name": "Hossein", "clpid": "Rokhsari-H" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Vahala", "given_name": "Kerry", "orcid": "0000-0003-1783-1380", "clpid": "Vahala-K-J" } ], "abstract": "We present results of an experimental study of the\noscillation frequency, linewidth, RF-spectrum and the phase\nnoise of a radiation-pressure-driven optomechanical oscillator in\na microtoroidal geometry. Through this study we identify the\ncritical parameters that can be used for tailoring the desired\ncharacteristics of this device.", "doi": "10.1109/FREQ.2006.275419", "isbn": "978-1-4244-0073-7", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2006", "pages": "405-408" }, { "id": "authors:6mv16-pms15", "collection": "authors", "collection_id": "6mv16-pms15", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ANAieeejssc05", "type": "article", "title": "A 10-Gb/s two-dimensional eye-opening monitor in 0.13-\u03bcm standard CMOS", "author": [ { "family_name": "Analui", "given_name": "Behnam", "clpid": "Analui-B" }, { "family_name": "Rylyakov", "given_name": "Alexander", "clpid": "Rylyakov-A" }, { "family_name": "Rylov", "given_name": "Sergey", "clpid": "Rylov-S" }, { "family_name": "Meghelli", "given_name": "Mounir", "clpid": "Meghelli-M" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "An eye-opening monitor (EOM) architecture that can capture a two-dimensional (2-D) map of the eye diagram of a high-speed data signal has been developed. Two single-quadrant phase rotators and one digital-to-analog converter (DAC) are used to generate rectangular masks with variable sizes and aspect ratios. Each mask is overlapped with the received eye diagram and the number of signal transitions inside the mask is recorded as error. The combination of rectangular masks with the same error creates error contours that overall provide a 2-D map of the eye. The authors have implemented a prototype circuit in 0.13-\u03bcm standard CMOS technology that operates up to 12.5 Gb/s at 1.2-V supply. The EOM maps the input eye to a 2-D error diagram with up to 68-dB mask error dynamic range. The left and right halves of the eyes are monitored separately to capture horizontally asymmetric eyes. The chip consumes 330 mW and operates reliably with supply voltages as low as 1 V at 10 Gb/s. The authors also present a detailed analysis that verifies if the measurements are in good agreement with the expected results.", "doi": "10.1109/JSSC.2005.856576", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2005-12-01", "series_number": "12", "volume": "40", "issue": "12", "pages": "2689-2699" }, { "id": "authors:0r82e-jjk94", "collection": "authors", "collection_id": "0r82e-jjk94", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:NATieeejssc05", "type": "article", "title": "A fully integrated 24-GHz phased-array transmitter in CMOS", "author": [ { "family_name": "Natarajan", "given_name": "Arun", "orcid": "0000-0003-3648-3844", "clpid": "Natarajan-A" }, { "family_name": "Komijani", "given_name": "Abbas", "clpid": "Komijani-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper presents the first fully integrated 24-GHz phased-array transmitter designed using 0.18-/spl mu/m CMOS transistors. The four-element array includes four on-chip CMOS power amplifiers, with outputs matched to 50 /spl Omega/, that are each capable of generating up to 14.5 dBm of output power at 24 GHz. The heterodyne transmitter has a two-step quadrature up-conversion architecture with local oscillator (LO) frequencies of 4.8 and 19.2 GHz, which are generated by an on-chip frequency synthesizer. Four-bit LO path phase shifting is implemented in each element at 19.2 GHz, and the transmitter achieves a peak-to-null ratio of 23 dB with raw beam-steering resolution of 7/spl deg/ for radiation normal to the array. The transmitter can support data rates of 500 Mb/s on each channel (with BPSK modulation) and occupies 6.8 mm /spl times/ 2.1 mm of die area.", "doi": "10.1109/JSSC.2005.857420", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2005-12-01", "series_number": "12", "volume": "40", "issue": "12", "pages": "2502-2514" }, { "id": "authors:nnnqm-vcb56", "collection": "authors", "collection_id": "nnnqm-vcb56", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ANAieeetmtt05", "type": "article", "title": "Data-dependent jitter in serial communications", "author": [ { "family_name": "Analui", "given_name": "Behnam", "clpid": "Analui-B" }, { "family_name": "Buckwalter", "given_name": "James F.", "clpid": "Buckwalter-J-F" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "We present a method for predicting data-dependent jitter (DDJ) introduced by a general linear time-invariant LTI system based on the system's unit step response. We express the exact DDJ of a first-order system and verify the validity of the solution experimentally. We then propose a perturbation technique to generalize the analytical expression for DDJ. We highlight the significance of the unit step response in characterizing DDJ and emphasize that bandwidth is not a complete measure for predicting DDJ. We separate the individual jitter contributions of prior bits and use the result to predict the DDJ of a general LTI system. In particular, we identify a dominant prior bit that signifies the well-known distribution of deterministic jitter, the two impulse functions. We also show a jitter minimization property of high-order LTI systems. We verify our generalized analytical expression of DDJ for several real systems including an integrated CMOS 10-Gb/s trans-impedance amplifier by comparing the theory and measurement results. The theory predicts the jitter with as low as only 7.5% error.", "doi": "10.1109/TMTT.2005.857118", "issn": "0018-9480", "publisher": "IEEE Transactions on Microwave Theory and Techniques", "publication": "IEEE Transactions on Microwave Theory and Techniques", "publication_date": "2005-11-01", "series_number": "11", "volume": "53", "issue": "11", "pages": "3388-3397" }, { "id": "authors:y535t-n5g32", "collection": "authors", "collection_id": "y535t-n5g32", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:KOMieeejssc05", "type": "article", "title": "A 24-GHz, +14.5-dBm fully integrated power amplifier in 0.18-\u03bcm CMOS", "author": [ { "family_name": "Komijani", "given_name": "Abbas", "clpid": "Komijani-A" }, { "family_name": "Natarajan", "given_name": "Arun", "orcid": "0000-0003-3648-3844", "clpid": "Natarajan-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A 24-GHz +14.5-dBm fully integrated power amplifier with on-chip 50-[ohm] input and output matching is demonstrated in 0.18-\u03bcm CMOS. The use of substrate-shielded coplanar waveguide structures for matching networks results in low passive loss and small die size. Simple circuit techniques based on stability criteria derived result in an unconditionally stable amplifier. The power amplifier achieves a power gain of 7 dB and a maximum single-ended output power of +14.5-dBm with a 3-dB bandwidth of 3.1 GHz, while drawing 100 mA from a 2.8-V supply. The chip area is 1.26 mm^2.", "doi": "10.1109/JSSC.2005.848143", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2005-09-01", "series_number": "9", "volume": "4", "issue": "9", "pages": "1901-1908" }, { "id": "authors:znn24-h0k29", "collection": "authors", "collection_id": "znn24-h0k29", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HAJprocieee05", "type": "article", "title": "Integrated phased array systems in silicon", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Hashemi", "given_name": "Hossein", "clpid": "Hashemi-H" }, { "family_name": "Natarajan", "given_name": "Arun", "orcid": "0000-0003-3648-3844", "clpid": "Natarajan-A" }, { "family_name": "Guan", "given_name": "Xiang", "clpid": "Guan-X" }, { "family_name": "Komijani", "given_name": "Abbas", "clpid": "Komijani-A" } ], "abstract": "Silicon offers a new set of possibilities and challenges for RF, microwave, and millimeter-wave applications. While the high cutoff frequencies of the SiGe heterojunction bipolar transistors and the ever-shrinking feature sizes of MOSFETs hold a lot of promise, new design techniques need to be devised to deal with the realities of these technologies, such as low breakdown voltages, lossy substrates, low-Q passives, long interconnect parasitics, and high-frequency coupling issues. As an example of complete system integration in silicon, this paper presents the first fully integrated 24-GHz eight-element phased array receiver in 0.18-\u03bcm silicon-germanium and the first fully integrated 24-GHz four-element phased array transmitter with integrated power amplifiers in 0.18-\u03bcm CMOS. The transmitter and receiver are capable of beam forming and can be used for communication, ranging, positioning, and sensing applications.", "doi": "10.1109/JPROC.2005.852231", "issn": "0018-9219", "publisher": "Proceedings of the IEEE", "publication": "Proceedings of the IEEE", "publication_date": "2005-09-01", "series_number": "9", "volume": "93", "issue": "9", "pages": "1637-1655" }, { "id": "authors:s676n-0kq86", "collection": "authors", "collection_id": "s676n-0kq86", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110819-071747535", "type": "book_section", "title": "A Wideband 77GHz, 17.5dBm Power Amplifier in Silicon", "book_title": "Proceedings of the IEEE 2005 Custom Integrated Circuits Conference", "author": [ { "family_name": "Komijani", "given_name": "Abbas", "clpid": "Komijani-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A 77GHz, +17.5dBm fully-integrated power amplifier (PA) with 50\u03a9 input and output matching is fabricated in a 0.12\u03bcm SiGe BiCMOS process. The power amplifier achieves a peak power gain of 17dB and a maximum single-ended output power of +17.5dBm with 12.8% of power-added efficiency (PAE). It has a 3dB bandwidth of 15GHz and draws 165mA from a 1.8V supply. Microstrip tubs are used as the transmission line structure resulting in large isolation between adjacent lines, enabling integration of the PA in a small area of 0.6mm.", "doi": "10.1109/CICC.2005.1568732", "isbn": "0-7803-9023-7", "publisher": "IEEE", "place_of_publication": "Piscataway, N.J.", "publication_date": "2005-09", "pages": "571-574" }, { "id": "authors:4z3fg-21j15", "collection": "authors", "collection_id": "4z3fg-21j15", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ANAieeetcsII05", "type": "article", "title": "Instantaneous Clockless Data Recovery and Demultiplexing", "author": [ { "family_name": "Analui", "given_name": "Behnam", "clpid": "Analui-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "An alternative architecture for instantaneous data recovery for burst-mode communication is introduced. The architecture can perform 1:n demultiplexing without additional clock recovery phase-locked loop or sampling blocks. A finite-state machine (FSM) is formed with combinational logic and analog LC transmission line delay cells in a feedback loop. The FSM responds to input data transitions instantaneously and sets the outputs. The system reduces unit interval jitter by a factor of n. The new architecture is demonstrated via a SiGe 1:2 clockless demultiplexer circuit that operates at 7.5 Gb/s.", "doi": "10.1109/TCSII.2005.850453", "issn": "1549-7747", "publisher": "IEEE", "publication": "IEEE Transactions on Circuits and Systems II: Express Briefs", "publication_date": "2005-08", "series_number": "8", "volume": "52", "issue": "8", "pages": "437-441" }, { "id": "authors:w2533-37483", "collection": "authors", "collection_id": "w2533-37483", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110825-151120289", "type": "book_section", "title": "A Solid-State Atomic Frequency Standard", "book_title": "2005 IEEE International Frequency Control Symposium and Exposition", "author": [ { "family_name": "White", "given_name": "Christopher J.", "clpid": "White-C-J" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper describes a new class of frequency\nreference. The frequency source uses the same operating\nprinciple as a passive atomic frequency standard; however, the device is entirely solid-state, removing many cost and\nreliability issues associated with gas phase atomic clocks. More specifically, the \"atomic resonance\" is derived from zero-field magnetic resonance transitions of the vanadium ion in magnesium oxide. The characteristics of these resonances will be described in detail. The apparatus for measuring the \"atomic\" resonances uses a microwave resonant cavity and frequency-discriminator circuit. Using integrated circuits, the radio-frequency signal processing functions can be implemented at very low cost in a reliable manufacturing process. We discuss the system design and the measurement sensitivity. The estimated short term stability is in the range of 10^(-8) to 10^(-9) @ 1 s. Advantages of the new frequency reference may include immunity to vibration, reduced aging compared to crystal oscillators, and immediate cold start.", "doi": "10.1109/FREQ.2005.1574061", "isbn": "0-7803-9052-0", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2005-08", "pages": "940-946" }, { "id": "authors:6n2th-b1m39", "collection": "authors", "collection_id": "6n2th-b1m39", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ANAmttsims05", "type": "book_section", "title": "Estimating data-dependent jitter of a general LTI system from step response", "book_title": "2005 IEEE MTT-S International Microwave Symposium Digest", "author": [ { "family_name": "Analui", "given_name": "Behnam", "clpid": "Analui-B" }, { "family_name": "Buckwalter", "given_name": "James", "orcid": "0000-0002-9390-0897", "clpid": "Buckwalter-J-F" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "We present a method for estimating data dependent jitter (DDJ) introduced by a general LTI system, based on the system's step response. A perturbation technique is used to generalize the analytical expression for DDJ. Different scales of DDJ are defined that characterize the probability distribution of jitter. In particular, we identify a dominant prior bit that signifies the well-known distribution of DDJ, the two impulse functions. We also highlight that system bandwidth is not a complete measure for predicting DDJ. We verify our generalized analytical expression of DDJ experimentally and show that estimation errors are less than 7.5%.", "doi": "10.1109/MWSYM.2005.1517087", "isbn": "0780388453", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2005-06-12", "pages": "1841-1844" }, { "id": "authors:2zqrh-k2g27", "collection": "authors", "collection_id": "2zqrh-k2g27", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110817-114618470", "type": "book_section", "title": "Fully Integrated RF CMOS Power Amplifiers - A Prelude to FulI Radio Integration", "book_title": "2005 IEEE Radio Frequency Integrated Circuits", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A fully integrated radio on a chip offers innumerable advantages and several challenges. We discuss some of these opportunities and challenges for a fully-integrated CMOS PA and see how the distributed active transformer (DAT) technology can overcome them.", "doi": "10.1109/RFIC.2005.1489837", "isbn": "0-7803-8983-2", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2005-06", "pages": "439-442" }, { "id": "authors:54za1-6ag81", "collection": "authors", "collection_id": "54za1-6ag81", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110825-080937821", "type": "book_section", "title": "A 24 GHz Phased-Array Transmitter in 0.18\u00b5m CMOS", "book_title": "42nd Design Automation Conference", "author": [ { "family_name": "Natarajan", "given_name": "Arun", "orcid": "0000-0003-3648-3844", "clpid": "Natarajan-A" }, { "family_name": "Komijani", "given_name": "Abbas", "clpid": "Komijani-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A fully-integrated 4-element phased array transmitter at 24 GHz with on-chip PAs is demonstrated in 0.18 \u00b5m CMOS. It has a beam-forming resolution of 10 degrees, a peak-to-null ratio of 23 dB, and 28 dB isolation between paths. Each PA can deliver up to +14 dBm into 50 \u03a9 in saturation. The die size is 6.8mm x 2.1mm. The transmitter bandwidth is more than 400MHz and supports up to 1 Gbit/s QPSK, facilitating a Gigabit wireless LAN solution.", "doi": "10.1109/DAC.2005.193871", "isbn": "1-59593-058-2", "publisher": "Association for Computing Machinery", "place_of_publication": "New York, NY", "publication_date": "2005-06", "pages": "551-552" }, { "id": "authors:q69fw-36m49", "collection": "authors", "collection_id": "q69fw-36m49", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:AFSieeejssc05", "type": "article", "title": "Nonlinear transmission lines for pulse shaping in silicon", "author": [ { "family_name": "Afshari", "given_name": "Ehsan", "clpid": "Afshari-E" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Nonlinear transmission lines (NLTL) are used for pulse shaping. We developed the theory of pulse propagation through the NLTL. The problem of a wide pulse degenerating into multiple pulses rather than a single pulse is solved by using a gradually scaled NLTL. We exploit certain favorable properties of accumulation-mode MOS varactors to design an NLTL that can simultaneously sharpen both rising and falling edges. There is a good agreement among the theory, simulations, and measurements.", "doi": "10.1109/JSSC.2005.843639", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2005-03-01", "series_number": "3", "volume": "40", "issue": "3", "pages": "744-752" }, { "id": "authors:hkwze-e7k27", "collection": "authors", "collection_id": "hkwze-e7k27", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HASieeetmtt05", "type": "article", "title": "A 24-GHz SiGe Phased-Array Receiver\u2014LO Phase-Shifting Approach", "author": [ { "family_name": "Hashemi", "given_name": "Hossein", "clpid": "Hashemi-H" }, { "family_name": "Guan", "given_name": "Xiang", "clpid": "Guan-X" }, { "family_name": "Komijani", "given_name": "Abbas", "clpid": "Komijani-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A local-oscillator phase-shifting approach is introduced to implement a fully integrated 24-GHz phased-array receiver using an SiGe technology. Sixteen phases of the local oscillator are generated in one oscillator core, resulting in a raw beam-forming accuracy of 4 bits. These phases are distributed to all eight receiving paths of the array by a symmetric network. The appropriate phase for each path is selected using high-frequency analog multiplexers. The raw beam-steering resolution of the array is better than 10 [degrees] for a forward-looking angle, while the array spatial selectivity, without any amplitude correction, is better than 20 dB. The overall gain of the array is 61 dB, while the array improves the input signal-to-noise ratio by 9 dB.", "doi": "10.1109/TMTT.2004.841218", "issn": "0018-9480", "publisher": "IEEE Transactions on Microwave Theory and Techniques", "publication": "IEEE Transactions on Microwave Theory and Techniques", "publication_date": "2005-02-01", "series_number": "2", "volume": "53", "issue": "2", "pages": "614-626" }, { "id": "authors:a09wf-vew30", "collection": "authors", "collection_id": "a09wf-vew30", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ANAisscc05", "type": "book_section", "title": "A 10Gb/s eye-opening monitor in 0.13\u03bcm CMOS", "book_title": "IEEE International Solid-State Circuits Conference, Digest of Technical Papers. ISSCC '05. San Francisco, CA", "author": [ { "family_name": "Analui", "given_name": "Behnam", "clpid": "Analui-B" }, { "family_name": "Rylyakov", "given_name": "Alexander", "clpid": "Rylyakov-A" }, { "family_name": "Rylov", "given_name": "Sergey", "clpid": "Rylov-S" }, { "family_name": "Meghelli", "given_name": "Mounir", "clpid": "Meghelli-M" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "An eye-opening monitor circuit in 0.13 \u03bcm CMOS operates from 1 to 12.5Gbit/s at 1.2V supply. It maps the input eye to a 2D error diagram with 68dB mask error dynamic range. Left and right halt of the eye are monitored separately to capture asymmetric eyes. Tested input amplitude is from 50 to 400mV. The chip consumes 330mW and works at 10Gb/s with a supply voltage as low as 1V.", "doi": "10.1109/ISSCC.2005.1494004", "isbn": "0780389042", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2005-02-01", "pages": "332-333 + 602" }, { "id": "authors:sx1qm-c8571", "collection": "authors", "collection_id": "sx1qm-c8571", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110517-090627598", "type": "book_section", "title": "Crosstalk-induced jitter equalization", "book_title": "Proceedings of the IEEE 2005 Custom Integrated Circuits Conference", "author": [ { "family_name": "Buckwalter", "given_name": "James", "clpid": "Buckwalter-J" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A novel jitter equalization circuit is presented that addresses crosstalk-induced jitter in high-speed communication links. A simplified model of electromagnetic coupling demonstrates the generation of crosstalk-induced jitter. This model suggests an equalizer that compensates for the data-induced electromagnetic coupling between adjacent links. Additionally, a data-dependent jitter equalizer that provides separate adjustments of rising and falling edge deviations is presented. The circuits are implemented using 130 nm MOSFETs and operate at 5-10Gb/s. The results demonstrate reduced deterministic jitter and lower bit-error rate. At 10Gb/s, the crosstalk-induced jitter equalizer opens the eye at BER of 10^(-12) from 17ps to 45ps.", "doi": "10.1109/CICC.2005.1568692", "isbn": "0-7803-9023-7", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2005", "pages": "409-412" }, { "id": "authors:f55vb-c4j85", "collection": "authors", "collection_id": "f55vb-c4j85", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:GUAieeejssc04b", "type": "article", "title": "A Fully Integrated 24-GHz Eight-Element Phased-Array Receiver in Silicon", "author": [ { "family_name": "Guan", "given_name": "Xiang", "clpid": "Guan-X" }, { "family_name": "Hashemi", "given_name": "Hossein", "clpid": "Hashemi-H" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper reports the first fully integrated 24-GHz eight-element phased-array receiver in a SiGe BiCMOS technology. The receiver utilizes a heterodyne topology and the signal combining is performed at an IF of 4.8 GHz. The phase-shifting with 4 bits of resolution is realized at the LO port of the first down-conversion mixer. A ring LC voltage-controlled oscillator (VCO) generates 16 different phases of the LO. An integrated 19.2-GHz frequency synthesizer locks the VCO frequency to a 75-MHz external reference. Each signal path achieves a gain of 43 dB, a noise figure of 7.4 dB, and an IIP3 of -11 dBm. The eight-path array achieves an array gain of 61 dB and a peak-to-null ratio of 20 dB and improves the signal-to-noise ratio at the output by 9 dB.", "doi": "10.1109/JSSC.2004.836339", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2004-12-01", "series_number": "12", "volume": "39", "issue": "12", "pages": "2311-2320" }, { "id": "authors:20wrx-ycr38", "collection": "authors", "collection_id": "20wrx-ycr38", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BUCcicc04", "type": "book_section", "title": "A 10Gb/s data-dependent jitter equalizer", "book_title": "IEEE Custom Integrated Circuits Conference, 2004, Orlando, FL, 3-6 October 2004", "author": [ { "family_name": "Buckwalter", "given_name": "James", "clpid": "Buckwalter-J-F" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "An equalization circuit is presented that reduces data-dependent jitter by aligning data transition deviations. This paper presents an analytic solution to data-dependent jitter and demonstrates its impact on the phase noise of the recovered clock. A data-dependent jitter equalizer is presented that compensates for impairment of the channel and lowers the phase noise of the recovered clock. The circuit is implemented in a SiGe BiCMOS process and operates at 10 Gb/s. It suppresses phase noise resulting from data-dependent jitter by 10 dB.", "isbn": "0-7803-8495-4", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2004-11-22", "pages": "39-42" }, { "id": "authors:j4wr4-zpv17", "collection": "authors", "collection_id": "j4wr4-zpv17", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BUCmttsims04", "type": "book_section", "title": "Data-dependent jitter and crosstalk-induced bounded uncorrelated jitter in copper interconnects", "book_title": "IEEE MTT-S International Microwave Symposium Digest, 2004", "author": [ { "family_name": "Buckwalter", "given_name": "James", "clpid": "Buckwalter-J-F" }, { "family_name": "Analui", "given_name": "Behnam", "clpid": "Analui-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper resolves the jitter impairment of non-return-to-zero data in transmission lines. The limited bandwidth of the transmission line introduces data-dependent jitter. Crosstalk between neighbouring lines results in bounded uncorrelated jitter in the data eye. An analytical approach to representing data-dependent jitter and crosstalk-induced bounded uncorrelated jitter is presented. Comparison with jitter measurements of microstrip lines on FR4 board demonstrated accuracy to within 15% of the predictions for deterministic jitter.", "doi": "10.1109/MWSYM.2004.1338895", "isbn": "0-7803-8331-1", "publisher": "IEEE", "place_of_publication": "Los Alamitos, CA", "publication_date": "2004-10-08", "pages": "1627-1630" }, { "id": "authors:7ygx6-aev32", "collection": "authors", "collection_id": "7ygx6-aev32", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110818-085428330", "type": "book_section", "title": "A breakdown voltage doubler for high voltage swing drivers", "book_title": "Proceedings of the IEEE 2004 Custom Integrated Circuits Conference", "author": [ { "family_name": "Mandegaran", "given_name": "Sam", "clpid": "Mandegaran-S" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A novel breakdown voltage (BV) doubler is introduced that makes it possible to generate high output voltage swings using transistors with low breakdown voltages. The timing analysis of the stage is used to optimize its dynamic response. A 10Gb/s optical modulator driver with a differential output voltage swing of 8V on a 50\u03a9 load was implemented in a SiGe BiCMOS process. It uses the BV-doubler topology to achieve output swings twice the collector-emitter breakdown voltage without stressing any single transistor.", "doi": "10.1109/CICC.2004.1358747", "isbn": "0-7803-8495-4", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2004-10", "pages": "103-106" }, { "id": "authors:jqfsx-98w27", "collection": "authors", "collection_id": "jqfsx-98w27", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111014-080912895", "type": "book_section", "title": "A 24GHz, +14.5dBm Fully-Integrated Power Amplifier in 0.18\u00b5m CMOS", "book_title": "Proceedings of the IEEE 2004 Custom Integrated Circuits Conference", "author": [ { "family_name": "Komijani", "given_name": "Abbas", "clpid": "Komijani-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A 24 GHz, +14.5 dBm fully-integrated power amplifier with 50 \u03a9 input and output matching is fabricated using 0.18 \u03bcm CMOS transistors. To enable this, a shielded-substrate coplanar waveguide transmission line structure is used to achieve low loss and small area. The power amplifier achieves a power gain of 7 dB and a maximum single-ended output power of +14.5 dBm with a 3 dB bandwidth of 3.1 GHz, while drawing 100 mA from a 2.8 V supply. The chip area is 1.26 mm^2.", "doi": "10.1109/CICC.2004.1358884", "isbn": "0-7803-8495-4", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2004-10", "pages": "561-564" }, { "id": "authors:t9h3d-7vs21", "collection": "authors", "collection_id": "t9h3d-7vs21", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:APAissccc04", "type": "book_section", "title": "Circular-geometry oscillators", "book_title": "IEEE International Solid-State Circuits Conference, ISSCC 2004.,", "author": [ { "family_name": "Aparicio", "given_name": "R.", "clpid": "Aparicio-R" }, { "family_name": "Hajimiri", "given_name": "A.", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "5.3GHz 0.18\u03bcm CMOS circular-geometry oscillator exploits high Q of slab inductors. The oscillator draws 10mA from 1.4V with a phase noise of -147.3dBc/Hz at 10MHz offset. A second 5.4GHz circular-geometry VCO has a tuning range of 8% with phase noise of -142.2dBc/Hz at 10MHz offset while drawing 12mA from a 1.8V supply.", "doi": "10.1109/ISSCC.2004.1332752", "isbn": "0-7803-8267-6", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2004-09-13" }, { "id": "authors:jr2qh-w6w38", "collection": "authors", "collection_id": "jr2qh-w6w38", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BUCieeetcsII04", "type": "article", "title": "Predicting data-dependent jitter", "author": [ { "family_name": "Buckwalter", "given_name": "James", "clpid": "Buckwalter-J-F" }, { "family_name": "Analui", "given_name": "Behnam", "clpid": "Analui-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "An analysis for calculating data-dependent jitter (DDJ) in a first-order system is introduced. The predicted DDJ features unique threshold crossing times with self-similar geometry. An approximation for DDJ in second-order systems is described in terms of the damping factor and natural frequency. Higher order responses demonstrate conditions under which unique threshold crossing times do not exist and total jitter is minimized. The DDJ predictions are verified with jitter measurements in a bandwidth-limited amplifier. The predictions for both first and second-order systems anticipate the features of the observed jitter.", "doi": "10.1109/TCSII.2004.834537", "issn": "1549-7747", "publisher": "IEEE", "publication": "IEEE Transactions on Circuits and Systems II: Express Briefs", "publication_date": "2004-09", "series_number": "9", "volume": "51", "issue": "9", "pages": "453-457" }, { "id": "authors:5veaq-wz633", "collection": "authors", "collection_id": "5veaq-wz633", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HAJieeecm04", "type": "article", "title": "Phased Array Systems in Silicon", "author": [ { "family_name": "Hajimiri", "given_name": "A.", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Komijani", "given_name": "A.", "clpid": "Komijani-A" }, { "family_name": "Natarjan", "given_name": "A.", "orcid": "0000-0003-3648-3844", "clpid": "Natarajan-A" }, { "family_name": "Chunara", "given_name": "R.", "clpid": "Chunara-R" }, { "family_name": "Guan", "given_name": "X.", "clpid": "Guan-X" }, { "family_name": "Hashemi", "given_name": "H.", "clpid": "Hashemi-H" } ], "abstract": "Phased array systems, a special case of MIMO systems, take advantage of spatial directivity and array gain to increase spectral efficiency. Implementing a phased array system at high frequency in a commercial silicon process technology presents several challenges. This article focuses on the architectural and circuit-level trade-offs involved in the design of the first silicon-based fully integrated phased array system operating at 24 GHz. The details of some of the important circuit building blocks are also discussed. The measured results demonstrate the feasibility of using integrated phased arrays for wireless communication and vehicular radar applications at 24 GHz.", "doi": "10.1109/MCOM.2004.1321403", "issn": "0163-6804", "publisher": "IEEE Communications Magazine", "publication": "IEEE Communications Magazine", "publication_date": "2004-08-01", "series_number": "8", "volume": "42", "issue": "8", "pages": "122-130" }, { "id": "authors:5bbzz-wx990", "collection": "authors", "collection_id": "5bbzz-wx990", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ANAieeejssc04", "type": "article", "title": "Bandwidth Enhancement for Transimpedance Amplifiers", "author": [ { "family_name": "Analui", "given_name": "Behnam", "clpid": "Analui-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A technique for bandwidth enhancement of a given amplifier is presented. Adding several interstage passive matching networks enables the control of transfer function and frequency response behavior. Parasitic capacitances of cascaded gain stages are isolated from each other and absorbed into passive networks. A simplified design procedure, using well-known low-pass filter component values, is introduced. To demonstrate the feasibility of the method, a CMOS transimpedance amplifier (TIA) is implemented in a 0.18-\u03bcm BiCMOS technology. It achieves 3 dB bandwidth of 9.2 GHz in the presence of a 0.5-pF photodiode capacitance. This corresponds to a bandwidth enhancement ratio of 2.4 over the amplifier without the additional passive networks. The trans-resistance gain is 54 dB[ohm], while drawing 55 mA from a 2.5-V supply. The input sensitivity of the TIA is -18 dBm for a bit error rate of 10^-12.", "doi": "10.1109/JSSC.2004.831783", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2004-08-01", "series_number": "8", "volume": "39", "issue": "8", "pages": "1263-1270" }, { "id": "authors:558ph-xfk60", "collection": "authors", "collection_id": "558ph-xfk60", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110916-101624435", "type": "book_section", "title": "An Active Analog Delay and the Delay Reference Loop", "book_title": "2004 IEEE Radio Frequency Integrated Circuits (RFIC) Symposium", "author": [ { "family_name": "Buckwalter", "given_name": "James", "clpid": "Buckwalter-J-F" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "contributor": [ { "family_name": "Deval", "given_name": "Y.", "clpid": "Deval-Y" } ], "abstract": "Wireline signal processing circuits such as transversal equalizers rely on true time delay. An active analog delay stage is proposed that requires a sixteenth of the area of a comparable LC delay line. A delay reference loop is also presented to tune the delay stage against process, voltage, and temperature variations. A reference signal is introduced to tune the delay. The impact of non-idealities must be considered, to understand the relationship between the reference frequency and the locked time delay. A SiGe BiCMOS implementation of the active analog delay stage and delay reference loop is presented that operates to 10 Gb/s.", "doi": "10.1109/RFIC.2004.1320512", "isbn": "0-7803-8333-8", "publisher": "IEEE", "place_of_publication": "Piscataway, N.J.", "publication_date": "2004-06-06", "pages": "17-20" }, { "id": "authors:p8267-e2v04", "collection": "authors", "collection_id": "p8267-e2v04", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110823-101014576", "type": "book_section", "title": "Multiple phase generation and distribution for a fully-integrated 24-GHz phased-array receiver in silicon", "book_title": "2004 IEEE Radio Frequency Integrated Circuits (RFIC) Symposium", "author": [ { "family_name": "Guan", "given_name": "Xiang", "clpid": "Guan-X" }, { "family_name": "Hashemi", "given_name": "Hossein", "clpid": "Hashemi-H" }, { "family_name": "Komijani", "given_name": "Abbas", "clpid": "Komijani-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "contributor": [ { "family_name": "Deval", "given_name": "Y.", "clpid": "Deval -Y" } ], "abstract": "This paper presents an on-chip multiphase LO generation and distribution technique used to implement a fully-integrated 24-GHz 8-path phased-array receiver in silicon. Sixteen LO phases are generated by an LC ring oscillator and distributed by a symmetric network to all eight paths. The 8-path array achieves a phase shifting resolution of 22.5\u00b0 and a total array gain of 61dB.", "doi": "10.1109/RFIC.2004.1320580", "isbn": "0-7803-8333-8", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2004-06", "pages": "229-232" }, { "id": "authors:es965-3et79", "collection": "authors", "collection_id": "es965-3et79", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111013-115154839", "type": "book_section", "title": "Reprogrammable, Wide Tuning Range 1.6GHz CMOS VCO with\n Low Phase Noise Variation", "book_title": "2004 IEEE Radio Frequency Integrated Circuits (RFIC) Symposium", "author": [ { "family_name": "Papalias", "given_name": "Tamara A.", "clpid": "Papalias-T-A" }, { "family_name": "Lee", "given_name": "Thomas T.", "clpid": "Lee-T-T" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Dutton", "given_name": "Robert W.", "clpid": "Dutton-R-W" }, { "family_name": "Lee", "given_name": "Thomas H.", "clpid": "Lee-T-H" } ], "abstract": "Phase noise can vary dramatically over the tying range of a VCO, but the published literature often obscures this fad by reporting phase noise measurements at only a small number of selected turning voltages. It is diffcult to obtain simultaneously a large tuning range, low phase noise, and small phase noise variation, particularly while accommodating manufacturing and packaging tolerances. This work describes the first use of native EPROM devices (available in every standard CMOS technology) and switched reactances to relax these tradeoffs. In addition to permitting post-packaging compensation for manufacturing variations, the inherent reprogrammability of they cells also enables the rapid prototyping and optional\nreconfiguration of RF and mixed-signal systems. This\ntechnology allows the realization of a fully-integrated\noscillator in 0.25\u03bcm CMOS with a phase noise variation of\nunder lOdB (compared with 40dB variation in a conventional\nimplementation) over a 1.25GHz to 1.92GHz (42%) tuning\nrange. The oscillator consumes 23mW from a 3V supply\nwhile exhibiting a phase noise of better than -93dBdHz at\n100kHz offset from a nominal 1.58GHz center frequency.", "doi": "10.1109/RFIC.2004.1320659", "isbn": "0-7803-8333-8", "publisher": "IEEE", "publication_date": "2004-06", "pages": "479-482" }, { "id": "authors:d7m7z-82693", "collection": "authors", "collection_id": "d7m7z-82693", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:GUAieeejssc04a", "type": "article", "title": "A 24-GHz CMOS Front-End", "author": [ { "family_name": "Guan", "given_name": "Xiang", "clpid": "Guan-X" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper reports the first 24-GHz CMOS front-end in a 0.18-\u00b5m process. It consists of a low-noise amplifier (LNA) and a mixer and downconverts an RF input at 24GHz to an IF of 5 GHz. It has a power gain of 27.5 dB and an overall noise figure of 7.7 dB with an input return loss, S[sub]11 of 21 dB consuming 20 mA from a 1.5-V supply. The LNA achieves a power gain of 15 dB and a noise figure of 6 dB on 16 mA of dc current. The LNA's input stage utilizes a common-gate with resistive feedthrough topology. The performance analysis of this topology predicts the experimental results with good accuracy.", "doi": "10.1109/JSSC.2003.821783", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2004-02-01", "series_number": "2", "volume": "39", "issue": "2", "pages": "368-373" }, { "id": "authors:ncmch-j3k74", "collection": "authors", "collection_id": "ncmch-j3k74", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110920-115356193", "type": "book_section", "title": "A Fully Integrated 24GHz 8-Path Phased-Array Receiver in Silicon", "book_title": "2004 IEEE International Solid-State Circuits Conference, Digest of Technical Papers", "author": [ { "family_name": "Hashemi", "given_name": "Hossein", "clpid": "Hashemi-H" }, { "family_name": "Guan", "given_name": "Xiang", "clpid": "Guan-X" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "contributor": [ { "family_name": "Fujino", "given_name": "L. C.", "clpid": "Fujino-L-C" } ], "abstract": "A fully integrated 8-channel phased-array receiver at 24 GHz is demonstrated. Each channel achieves a gain of 43 dB, noise figure of 8 dB, and an IIP3 of -11dBm, consuming 29 mA of current from a 2.5 V supply. The 8-channel array has a beam-forming resolution of 22.5\u00b0, a peak-to- ratio of 20 dB (4-bits), a total array gain of 61 dB, and improves the signal-to-noise ratio by 9 dB.", "doi": "10.1109/ISSCC.2004.1332758", "isbn": "0-7803-8267-6", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2004-02", "pages": "390-391" }, { "id": "authors:2s3fh-p3t51", "collection": "authors", "collection_id": "2s3fh-p3t51", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:WUHieeejssc03", "type": "article", "title": "Integrated Transversal Equalizers in High-Speed Fiber-Optic Systems", "author": [ { "family_name": "Wu", "given_name": "Hui", "clpid": "Wu-H" }, { "family_name": "Tierno", "given_name": "Jose A.", "clpid": "Tierno-J-A" }, { "family_name": "Pepeljugoski", "given_name": "Petar", "clpid": "Pepeljugoski-P" }, { "family_name": "Schaub", "given_name": "Jeremy", "clpid": "Schaub-J" }, { "family_name": "Gowda", "given_name": "Sudhir", "clpid": "Gowda-S" }, { "family_name": "Kash", "given_name": "Jeffrey A.", "clpid": "Kash-J-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Intersymbol interference (ISI) caused by intermodal dispersion in multimode fibers is the major limiting factor in the achievable data rate or transmission distance in high-speed multimode fiber-optic links for local area networks applications. Compared with optical-domain and other electrical-domain dispersion compensation methods, equalization with transversal filters based on distributed circuit techniques presents a cost-effective and low-power solution. The design of integrated distributed transversal equalizers is described in detail with focus on delay lines and gain stages. This seven-tap distributed transversal equalizer prototype has been implemented in a commercial 0.18-\u00b5m SiGe BiCMOS process for 10-Gb/s multimode fiber-optic links. A seven-tap distributed transversal equalizer reduces the ISI of a 10-Gb/s signal after 800 m of 50-\u00b5m multimode fiber from 5 to 1.38 dB, and improves the bit-error rate from about 10^-5 to less than 10^-12.", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2003-12-01", "series_number": "12", "volume": "38", "issue": "12", "pages": "2131-2137" }, { "id": "authors:jx712-nny11", "collection": "authors", "collection_id": "jx712-nny11", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:WUHcicc03", "type": "book_section", "title": "Differential 4-tap and 7-tap transverse filters in SiGe for 10Gb/s multimode fiber optic link equalization", "book_title": "Proceedings of the IEEE 2003 Custom Integrated Circuits Conference, DoubleTree Hotel, September 21-24, 2003, San Jose, California", "author": [ { "family_name": "Wu", "given_name": "Hui", "clpid": "Wu-H" }, { "family_name": "Tierno", "given_name": "J.", "clpid": "Tierno-J-A" }, { "family_name": "Pepeljugoski", "given_name": "P.", "clpid": "Pepeljugoski-P" }, { "family_name": "Schaub", "given_name": "J.", "clpid": "Schaub-J" }, { "family_name": "Gowda", "given_name": "S.", "clpid": "Gowda-S" }, { "family_name": "Kash", "given_name": "J.", "clpid": "Kash-J-A" }, { "family_name": "Hajimiri", "given_name": "A.", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Differential 4-tap and 7-tap transverse filters are designed in a 0.18 \u00b5m SiGe BiCMOS technology for equalization of 10Gb/s multimode fiber optic signals. The 7-tap equalizer reduced the ISI of a 10Gb/s signal received through 300m of 50 \u00b5m noncompliant next generation multimode fiber from 4.2dB to 0.8dB. The circuit dissipates 40mW from a 3.3V supply.", "doi": "10.1109/ISSCC.2003.1234257", "isbn": "0-7803-7707-9", "publisher": "IEEE", "place_of_publication": "Los Alamitos, CA", "publication_date": "2003-10-20", "pages": "10.4" }, { "id": "authors:w8npb-1fj62", "collection": "authors", "collection_id": "w8npb-1fj62", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111020-133215948", "type": "book_section", "title": "Bringing Optics Inside the Box: Recent Progress and Future Trends", "book_title": "2003 IEEE LEOS Annual Meeting Conference Proceedings", "author": [ { "family_name": "Kash", "given_name": "J.", "clpid": "Kash-J" }, { "family_name": "Baks", "given_name": "C.", "clpid": "Baks-C" }, { "family_name": "Gowda", "given_name": "S.", "clpid": "Gowda-S" }, { "family_name": "Graham", "given_name": "L.", "clpid": "Graham-L" }, { "family_name": "Hajimiri", "given_name": "A.", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Haymes", "given_name": "C.", "clpid": "Haymes-C" }, { "family_name": "Jewell", "given_name": "J.", "clpid": "Jewell-J" }, { "family_name": "Kucharski", "given_name": "D.", "clpid": "Kucharski-D" }, { "family_name": "Kuchta", "given_name": "D.", "clpid": "Kuchta-D" }, { "family_name": "Kwark", "given_name": "Y.", "clpid": "Kwark-Y" }, { "family_name": "Pepeljugoski", "given_name": "P.", "clpid": "Pepeljugoski-P" }, { "family_name": "Schaub", "given_name": "J.", "clpid": "Schaub-J" }, { "family_name": "Schuster", "given_name": "C.", "orcid": "0000-0002-1948-2367", "clpid": "Schuster-C" }, { "family_name": "Tierno", "given_name": "J.", "clpid": "Tierno-J" }, { "family_name": "Wu", "given_name": "H.", "clpid": "Wu-H" } ], "abstract": "Needs and requirements for optical interconnects in next generation servers are outlined. Related results on equalizing and characterizing high speed multimode links, building and testing parallel 12 \u00d7 10 Gbit/sec transceivers, and highly parallel silicon photodetectors are presented.", "doi": "10.1109/LEOS.2003.1251644", "isbn": "0-7803-7888-1", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2003-10", "pages": "148-149" }, { "id": "authors:p8rws-53c82", "collection": "authors", "collection_id": "p8rws-53c82", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:AFScicc03", "type": "book_section", "title": "Non-linear transmission lines for pulse shaping in silicon", "book_title": "IEEE Custom Integrated Circuits Conference (CICC '03)", "author": [ { "family_name": "Afshari", "given_name": "Ehsan", "clpid": "Afshari-E" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Non-linear transmission limes (NLTL) are used for pulse shaping. We developed the theory of pulse propagation through the NLTL. The problem of a wide pulse degenerating into multiple pulses rather than a single pulse is solved by using a novel gradually scaled NLTL. We exploit certain favorable properties of accumulation mode MOS varactors to design an NLTL that can sharpen both rising and falling edges, simultaneously. There is a good agreement among the theory,\nsimulations, and measurements.", "doi": "10.1109/CICC.2003.1249366", "isbn": "0780378423", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2003-09-01", "pages": "91-94" }, { "id": "authors:1fpe7-dyq57", "collection": "authors", "collection_id": "1fpe7-dyq57", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ANAcicc03", "type": "book_section", "title": "Statistical analysis of integrated passive delay lines", "book_title": "IEEE Custom Integrated Circuits Conference (CICC 2003)", "author": [ { "family_name": "Analui", "given_name": "Behnam", "clpid": "Analui-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Statistical properties of integrated passive LC delay lines are investigated. A new variation using spiral inductors and vertical parallel plate (VPP) capacitors is introduced whose delay is primarily determined by the lateral dimensions, resulting in very accurate and repeatable delays. An MIM-based version of this line is also fabricated for comparison. Additionally, LC delay-based oscillators are implemented to compare the variations in active and passive delay elements. Experimental data is obtained from measurement of 27 and 47 sites on two wafers from two different process runs, respectively. The measurements show 0.6% delay variations for VPP-based delay line compared to 1.0% for its MIM-based counterpart.", "doi": "10.1109/CICC.2003.1249370", "isbn": "0780378423", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2003-09-01", "pages": "107-110" }, { "id": "authors:ew4mh-9x724", "collection": "authors", "collection_id": "ew4mh-9x724", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:KEEieeetmtt03", "type": "article", "title": "The Class-E/F Family of ZVS Switching Amplifiers", "author": [ { "family_name": "Kee", "given_name": "Scott D.", "clpid": "Kee-S-D" }, { "family_name": "Aoki", "given_name": "Ichiro", "clpid": "Aoki-I" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Rutledge", "given_name": "David", "clpid": "Rutledge-D-B" } ], "abstract": "A new family of switching amplifiers, each member having some of the features of both class E and inverse F, is introduced. These class-E/F amplifiers have class-E features such as incorporation of the transistor parasitic capacitance into the circuit, exact truly switching time-domain solutions, and allowance for zero-voltage-switching operation. Additionally, some number of harmonics may be tuned in the fashion of inverse class F in order to achieve more desirable voltage and current waveforms for improved performance. Operational waveforms for several implementations are presented, and efficiency estimates are compared to class-E.", "doi": "10.1109/TMTT.2003.812564", "issn": "0018-9480", "publisher": "IEEE Transactions on Microwave Theory and Techniques", "publication": "IEEE Transactions on Microwave Theory and Techniques", "publication_date": "2003-06-01", "series_number": "6", "volume": "51", "issue": "6", "pages": "1677-1690" }, { "id": "authors:dyf8n-sr140", "collection": "authors", "collection_id": "dyf8n-sr140", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:AOKrfic03", "type": "book_section", "title": "A fully-integrated 1.8-V, 2.8-W, 1.9-GHz, CMOS power amplifier", "book_title": "IEEE Radio Frequency Integrated Circuits (RFIC 2003) Symposium", "author": [ { "family_name": "Aoki", "given_name": "I.", "clpid": "Aoki-I" }, { "family_name": "Kee", "given_name": "S.", "clpid": "Kee-S" }, { "family_name": "Rutledge", "given_name": "D.", "clpid": "Rutledge-D-B" }, { "family_name": "Hajimiri", "given_name": "A.", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "contributor": [ { "family_name": "Quach", "given_name": "Tina" } ], "abstract": "This paper demonstrated the first 2-stage, 2.8W, 1.8V, 1.9GHz fully-integrated DAT power amplifier with 50\u03a9 input and output matching using 0.18\u03bcm CMOS transistors. It has a small-signal gain of 27dB. The amplifier provides 2.8W of power into a 50\u03a9 load with a PAE of 50%.", "isbn": "0-7803-7694-3", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2003-06", "pages": "199-202" }, { "id": "authors:haq0x-nke82", "collection": "authors", "collection_id": "haq0x-nke82", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HAMieeejssc03", "type": "article", "title": "Virtual damping and Einstein relation in oscillators", "author": [ { "family_name": "Ham", "given_name": "Donhee", "clpid": "Ham-D" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper presents a new physical theory of oscillator phase noise. Built around the concept of phase diffusion, this work bridges the fundamental physics of noise and existing oscillator phase-noise theories. The virtual damping of an ensemble of oscillators is introduced as a measure of phase noise. The explanation of linewidth compression through virtual damping provides a unified view of resonators and oscillators. The direct correspondence between phase noise and the Einstein relation is demonstrated, which reveals the underlying physics of phase noise. The validity of the new approach is confirmed by consistent experimental agreement.", "doi": "10.1109/JSSC.2002.808283", "issn": "0018-9200", "publisher": "IEEE", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2003-03", "series_number": "3", "volume": "38", "issue": "3", "pages": "407-418" }, { "id": "authors:g6ykc-20t19", "collection": "authors", "collection_id": "g6ykc-20t19", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:APAieeejssc02b", "type": "article", "title": "A Noise-Shifting Differential Colpitts VCO", "author": [ { "family_name": "Aparicio", "given_name": "Roberto", "clpid": "Aparicio-R" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A novel noise-shifting differential Colpitts VCO is presented. It uses current switching to lower phase noise by cyclostationary noise alignment and improve the start-up condition. A design strategy is also devised to enhance the phase noise performance of quadrature coupled oscillators. Two integrated VCOs are presented as design examples.", "doi": "10.1109/JSSC.2002.804354", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2002-12-01", "series_number": "12", "volume": "37", "issue": "12", "pages": "1728-1736" }, { "id": "authors:b2gde-f7w23", "collection": "authors", "collection_id": "b2gde-f7w23", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:WHIel02", "type": "article", "title": "Phase noise in distributed oscillators", "author": [ { "family_name": "White", "given_name": "C. J.", "clpid": "White-C-J" }, { "family_name": "Hajimiri", "given_name": "A.", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "The phase noise of a distributed oscillator is evaluated very simply by identifying an effective capacitance equal to the total capacitance distributed along the transmission lines. The contributions of the various passive and active noise sources to the total phase noise are calculated revealing several guidelines for improved distributed oscillator designs.", "doi": "10.1049/el:20020982", "issn": "0013-5194", "publisher": "Electronics Letters", "publication": "Electronics Letters", "publication_date": "2002-11-07", "series_number": "23", "volume": "38", "issue": "23", "pages": "1453-1454" }, { "id": "authors:j5bmn-30r91", "collection": "authors", "collection_id": "j5bmn-30r91", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111103-080251094", "type": "book_section", "title": "A 24GHz CMOS Front-end", "author": [ { "family_name": "Guan", "given_name": "Xiang", "clpid": "Guan-X" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper reports the first 24GHz 0.18-\u00b5m CMOS front-end. It down-converts an RF input at 24GHz range to an IF of 5GHz range with a power gain of 27.5dB and an overall noise figure of 7.7dB. It achieves an input return loss, S_(11) of -21dB drawing 43mA from a 1.5V supply. The LNA achieves a voltage gain of 22dB and a noise figure of 6dB consuming 16mA of dc current. This performance is achieved through an analysis of the LNA showing that the NF and gain of the common-gate stage scale more gracefully with frequency and hence it is the topology of choice for very high frequency front-ends.", "publisher": "IEEE", "publication_date": "2002-09" }, { "id": "authors:2byad-fk373", "collection": "authors", "collection_id": "2byad-fk373", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111101-115243350", "type": "book_section", "title": "Multi-Pole Bandwidth Enhancement Technique for Trans-impedance Amplifiers", "book_title": "ESSCIRC 2002", "author": [ { "family_name": "Analui", "given_name": "Behnam", "clpid": "Analui-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "contributor": [ { "family_name": "Baschirotto", "given_name": "Andrea", "clpid": "Baschirotto-A" }, { "family_name": "Malcovati", "given_name": "Piero", "clpid": "Malcovati-P" } ], "abstract": "A new technique for bandwidth enhancement of amplifiers is developed. Adding several passive networks, which can be designed independently, enables the control of transfer function and frequency response behavior. Parasitic capacitances of cascaded gain stages are isolated from each other and absorbed into passive networks. A simplified design procedure, using well-known filter component values is introduced. To demonstrate the feasibility of the method, a CMOS trans-impedance amplifier is implemented in 0.18\u00b5m BiCMOS technology. It achieves 9.2GHz bandwidth in the presence of 0.5pF photo diode capacitance and a trans-resistance gain of 54dB\u03a9, while drawing 55mA from a 2.5V supply.", "isbn": "8890084790", "publisher": "University of Bologna", "place_of_publication": "Bologna, Italy", "publication_date": "2002-09", "pages": "303-306" }, { "id": "authors:4js4e-9ta51", "collection": "authors", "collection_id": "4js4e-9ta51", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BOHmttsim02", "type": "book_section", "title": "Demonstration of a switchless Class E/Fodd dual-band power amplifier", "book_title": "IEEE MTT-S International Microwave Symposium Digest, Seattle, WA, 2-7 June 2002", "author": [ { "family_name": "Bohn", "given_name": "Florian", "clpid": "Bohn-F" }, { "family_name": "Kee", "given_name": "Scott", "clpid": "Kee-S-D" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "contributor": [ { "family_name": "Hamilton", "given_name": "Rob" }, { "family_name": "Chiang", "given_name": "Norman" } ], "abstract": "A 250 W dual-band power amplifier belonging to the Class E/F switching amplifier family is presented. The amplifier operates in the 7 MHz and 10 MHz HAM bands, achieving 16 dB and 15 d B gain with power added efficiencies (PAE) of 92% and 87% in those bands, respectively. It utilizes dual-resonant passive input and output networks to achieve high-efficiency Class E/Fodd operation at both frequencies of operation, allowing the same passive networks to be used for both frequency bands without the use of band-select switches.", "doi": "10.1109/MWSYM.2002.1012170", "isbn": "0-7803-7239-5", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2002-06", "pages": "1631-1634" }, { "id": "authors:4m4vy-2je30", "collection": "authors", "collection_id": "4m4vy-2je30", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111103-085201628", "type": "book_section", "title": "Virtual damping in oscillators", "book_title": "Proceedings of the IEEE 2002 Custom Integrated Circuits Conference", "author": [ { "family_name": "Ham", "given_name": "Donhee", "clpid": "Ham-D" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "This paper presents a new point of view of oscillator noise, bringing transparent insight into phase noise. This work bridges the fundamental physics of noise and existing oscillator phase noise theories and reveals the direct correspondence of phase noise and the Einstein relation. The concept of virtual damping is presented utilizing an ensemble of oscillators as a measure of phase noise. The explanation of the linewidth narrowing through virtual damping results in a clear definition of loaded and unloaded quality factors of an oscillator. The validity of this new approach is verified by excellent experimental agreement.", "doi": "10.1109/CICC.2002.1012799", "isbn": "0-7803-7250-6", "publisher": "IEEE", "place_of_publication": "Piscataway, N.J.", "publication_date": "2002-05", "pages": "213-216" }, { "id": "authors:56ebc-6qa97", "collection": "authors", "collection_id": "56ebc-6qa97", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:APAieeejssc02a", "type": "article", "title": "Capacity limits and matching properties of integrated capacitors", "author": [ { "family_name": "Aparicio", "given_name": "Roberto", "clpid": "Aparicio-R" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Theoretical limits for the capacitance density of integrated capacitors with combined lateral and vertical field components are derived. These limits are used to investigate the efficiency of various capacitive structures such as lateral flux and quasifractal capacitors. This study leads to two new capacitor structures with high lateral-field efficiencies. These new capacitors demonstrate larger capacities, superior matching properties, tighter tolerances, and higher self-resonance frequencies than the standard horizontal parallel plate and previously reported lateral-field capacitors, while maintaining comparable quality factors. These superior qualities are verified by simulation and experimental results.", "doi": "10.1109/4.987091", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2002-03-01", "series_number": "3", "volume": "37", "issue": "3", "pages": "384-393" }, { "id": "authors:rtpz5-41f87", "collection": "authors", "collection_id": "rtpz5-41f87", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:AOKieeejssc02", "type": "article", "title": "Fully integrated CMOS power amplifier design using the distributed active-transformer architecture", "author": [ { "family_name": "Aoki", "given_name": "Ichiro", "clpid": "Aoki-I" }, { "family_name": "Kee", "given_name": "Scott D.", "clpid": "Kee-S-D" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A novel on-chip impedance matching and power-combining method, the distributed active transformer is presented. It combines several low-voltage push-pull amplifiers efficiently with their outputs in series to produce a larger output power while maintaining a 50-\u03a9 match. It also uses virtual ac grounds and magnetic couplings extensively to eliminate the need for any off-chip component, such as tuned bonding wires or external inductors. Furthermore, it desensitizes the operation of the amplifier to the inductance of bonding wires making the design more reproducible. To demonstrate the feasibility of this concept, a 2.4-GHz 2-W 2-V truly fully integrated power amplifier with 50-\u03a9 input and output matching has been fabricated using 0.35-\u03bcm CMOS transistors. It achieves a power added efficiency (PAE) of 41 % at this power level. It can also produce 450 mW using a 1-V supply. Harmonic suppression is 64 dBc or better. This new topology makes possible a truly fully integrated watt-level gigahertz range low-voltage CMOS power amplifier for the first time.", "doi": "10.1109/4.987090", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2002-03-01", "series_number": "3", "volume": "37", "issue": "3", "pages": "371-383" }, { "id": "authors:8pct1-fwy06", "collection": "authors", "collection_id": "8pct1-fwy06", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HAJieeecm02", "type": "article", "title": "Distributed Integrated Circuits: An Alternative Approach to High-Frequency Design", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Distributed integrated circuits are presented as a methodology to design high-frequency communication building blocks. Distributed circuits operate based on multiple parallel signal paths working in synchronization that can be used to enhance the frequency of operation, combine power, and enhance the robustness of the design. These multiple signal paths usually result in strong couplings inside the circuit that necessitate\na treatment spanning architecture, circuits, devices, and electromagnetic levels of abstraction.", "doi": "10.1109/35.983925", "issn": "0163-6804", "publisher": "IEEE Communications Magazine", "publication": "IEEE Communications Magazine", "publication_date": "2002-02-01", "series_number": "2", "volume": "40", "issue": "2", "pages": "168-173" }, { "id": "authors:qthcc-3zp42", "collection": "authors", "collection_id": "qthcc-3zp42", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:APAisscc02", "type": "book_section", "title": "A CMOS differential noise-shifting Colpitts VCO", "book_title": "IEEE International Solid-State Circuits Conference, Digest of Technical Papers. ISSCC 2002, San Francisco, CA, 3-7 February 2002", "author": [ { "family_name": "Aparicio", "given_name": "Roberto", "clpid": "Aparicio-R" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A 0.35 \u03bcm VCO uses current switching to increase voltage swing, lower phase noise by cyclostationary noise alignment, and improve startup reliability. A CMOS VCO in a 3-metal, 0.35 \u03bcm process has -139 dBc/Hz phase noise at 3 MHz offset from a 1.8 GHz carrier and 30% of continuous tuning using inductors with Q of 6 and 4 mA dc current.", "doi": "10.1109/ISSCC.2002.993045", "isbn": "0-7803-7335-9", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2002-02" }, { "id": "authors:9b0pp-sp920", "collection": "authors", "collection_id": "9b0pp-sp920", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:AOKieeemtt02", "type": "article", "title": "Distributed active transformer - a new power-combining andimpedance-transformation technique", "author": [ { "family_name": "Aoki", "given_name": "Ichiro", "clpid": "Aoki-I" }, { "family_name": "Kee", "given_name": "Scott D.", "clpid": "Kee-S-D" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "In this paper, we compare the performance of the newly introduced distributed active transformer (DAT) structure to that of conventional on-chip impedance-transformations methods. Their fundamental power-efficiency limitations in the design of high-power fully integrated amplifiers in standard silicon process technologies are analyzed. The DAT is demonstrated to be an efficient impedance-transformation and power-combining method, which combines several low-voltage push-pull amplifiers in series by magnetic coupling. To demonstrate the validity of the new concept, a 2.4-GHz 1.9-W 2-V fully integrated power-amplifier achieving a power-added efficiency of 41% with 50-\u03a9 input and output matching has been fabricated using 0.35-\u03bcm CMOS transistors", "doi": "10.1109/22.981284", "issn": "0018-9480", "publisher": "IEEE Transactions on Microwave Theory and Techniques", "publication": "IEEE Transactions on Microwave Theory and Techniques", "publication_date": "2002-01-01", "series_number": "1, pt.", "volume": "50", "issue": "1, pt.", "pages": "316-331" }, { "id": "authors:p6zms-zhr15", "collection": "authors", "collection_id": "p6zms-zhr15", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HASieeetmtt02", "type": "article", "title": "Concurrent multiband low-noise amplifiers -- theory, design, and applications", "author": [ { "family_name": "Hashemi", "given_name": "Hossein", "clpid": "Hashemi-H" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "The concept of concurrent multiband low-noise-amplifiers (LNAs) is introduced. A systematic way to design concurrent multiband integrated LNAs in general is developed. Applications of concurrent multiband LNAs in concurrent multiband receivers together with receiver architecture are discussed. Experimental results of a dual-band LNA implemented in a 0.35-\u03bcm CMOS technology as a demonstration of the concept and theory is presented.", "doi": "10.1109/22.981282", "issn": "0018-9480", "publisher": "IEEE Transactions on Microwave Theory and Techniques", "publication": "IEEE Transactions on Microwave Theory and Techniques", "publication_date": "2002-01-01", "series_number": "1", "volume": "50", "issue": "1", "pages": "288-301" }, { "id": "authors:8tyjy-3p546", "collection": "authors", "collection_id": "8tyjy-3p546", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HAMieeejssc01", "type": "article", "title": "Concepts and methods in optimization of integrated LC VCOs", "author": [ { "family_name": "Ham", "given_name": "Donhee", "clpid": "Ham-D" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Underlying physical mechanisms controlling the noise properties of oscillators are studied. This treatment shows the importance of inductance selection for oscillator noise optimization. A design strategy centered around an inductance selection scheme is executed using a practical graphical optimization method to optimize phase noise subject to design constraints such as power dissipation, tank amplitude, tuning range, startup condition, and diameters of spiral inductors. The optimization technique is demonstrated through a design example, leading to a 2.4-GHz fully integrated, LC voltage-controlled oscillator (VCO) implemented using 0.35-\u03bcm MOS transistors. The measured phase-noise values are -121, -117, and -115 dBc/Hz at 600-kHz offset from 1.91, 2.03, and 2.60-GHz carriers, respectively. The VCO dissipates 4 mA from a 2.5-V supply voltage. The inversion mode MOSCAP tuning is used to achieve 26% of tuning range. Two figures of merit for performance comparison of various oscillators are introduced and used to compare this work to previously reported results.", "doi": "10.1109/4.924852", "issn": "0018-9200", "publisher": "IEEE", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2001-06", "series_number": "6", "volume": "36", "issue": "6", "pages": "896-909" }, { "id": "authors:zk3ds-yj770", "collection": "authors", "collection_id": "zk3ds-yj770", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111117-120951431", "type": "book_section", "title": "Concurrent Dual-Band CMOS Low Noise Amplifiers and Receiver Architectures", "book_title": "2001 Symposium on VLSI Circuits", "author": [ { "family_name": "Hashemi", "given_name": "Hossein", "clpid": "Hashemi-H" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A new concurrent dual-band receiver architecture is introduced that is capable of simultaneous operation at two different frequency bands. The concurrent operation results in higher bandwidth, lower total power dissipation and less sensitivity to channel variations. The architecture uses a novel concurrent dual-band low noise amplifier (LNA), combined with an elaborate frequency conversion scheme to reject the image bands. A general methodology for the design of concurrent LNAs is provided that makes it possible to achieve simultaneous narrowband gain and matching at multiple frequencies. The methodology is demonstrated by implementing an integrated dual-band concurrent LNA using 0.35 \u03bcm CMOS transistors. The LNA provides narrow-band gain and matching at 2.45 GHz and 5.25 GHz bands, simultaneously. It drains 4 mA of current and achieves voltage gains of 14 dB and 15.5 dB, input return losses of 25 dB and 15 dB, and noise figures of 2.3 dB and 4.5 dB at these two bands, respectively.", "doi": "10.1109/VLSIC.2001.934254", "isbn": "4-89114-014-3", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2001-06", "pages": "247-250" }, { "id": "authors:m5yxt-bq245", "collection": "authors", "collection_id": "m5yxt-bq245", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:AOKcicc01", "type": "book_section", "title": "A 2.4-GHz, 2.2-W, 2-V fully-integrated CMOS circular-geometry active-transformer power amplifier", "book_title": "IEEE Conference on Custom Integrated Circuits (CICC 2001), San Diego, CA, 6-9 May 2001", "author": [ { "family_name": "Aoki", "given_name": "Ichiro", "clpid": "Aoki-I" }, { "family_name": "Kee", "given_name": "Scott D.", "clpid": "Kee-S-D" }, { "family_name": "Rutledge", "given_name": "David", "clpid": "Rutledge-D-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A 2.4-GHz, 2.2-W, 2-V fully integrated circular geometry power amplifier with 50 \u03a9 input and output matching is fabricated using 2.5V, 0.35 pm CMOS transistors. It can also produce 450mW using a 1V supply. Harmonic suppression is 64dB or better. An on-chip circular-geometry active-transformer is used to combine several push-pull low-voltage amplifiers efficiently to produce a larger output power while maintaining a 50 \u03a9 match. This new on-chip power combining and impedance matching method uses virtual ac grounds and magnetic couplings extensively to eliminate the need for any off-chip component such as wirebonds. It also desensitizes the operation of the amplifier to the inductance of bonding wires and makes the design more reproducible. This new topology makes possible a fully-integrated 2.2W, 2.4GHz, low voltage CMOS power amplifier for the first time.", "doi": "10.1109/CICC.2001.929723", "isbn": "0-7803-6591-7", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2001-05", "pages": "57-60" }, { "id": "authors:9cbmc-jj058", "collection": "authors", "collection_id": "9cbmc-jj058", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:WUHieeejssc01", "type": "article", "title": "Silicon-based distributed voltage-controlled oscillators", "author": [ { "family_name": "Wu", "given_name": "Hui", "clpid": "Wu-H" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Distributed voltage-controlled oscillators (DVCOs) are presented as a new approach to the design of silicon VCOs at microwave frequencies. In this paper, the operation of distributed oscillators is analyzed and the general oscillation condition is derived, resulting in analytical expressions for the frequency and amplitude. Two tuning techniques for DVCOs are demonstrated, namely, the inherent-varactor tuning and delay-balanced current-steering tuning. A complete analysis of the tuning techniques is presented. CMOS and bipolar DVCOs have been designed and fabricated in a 0.35-\u03bcm BiCMOS process. A 10-GHz CMOS DVCO achieves a tuning range of 12% (9.3-10.5 GHz) and a phase noise of -103 dBc/Hz at 600 kHz offset from the carrier. The oscillator provides an output power of -4.5 dBm without any buffering, drawing 14 mA of dc current from a 2.5-V power supply. A 12-GHz bipolar DVCO consuming 6 mA from a 2.5-V power supply is also demonstrated. It has a tuning range of 26% with a phase noise of -99 dBc/Hz at 600 kHz offset from the carrier.", "doi": "10.1109/4.910488", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2001-03-01", "series_number": "3", "volume": "36", "issue": "3", "pages": "493-502" }, { "id": "authors:85fa7-4bq31", "collection": "authors", "collection_id": "85fa7-4bq31", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HUWIsscc01", "type": "book_section", "title": "A 19 GHz 0.5 mW 0.35 \u03bcm CMOS frequency divider with shunt-peaking locking-range enhancement", "book_title": "IEEE International Solid-State Circuits Conference, 2001. Digest of Technical Papers. ISSCC. San Francisco, 5-7 February 2001", "author": [ { "family_name": "Wu", "given_name": "Hui", "clpid": "Wu-H" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A frequency divider is an essential building block and one of the major sources of power dissipation in widely-used frequency synthesizers. As the output frequency of the synthesizer increases, the trade-off between the speed and power dissipation of dividers becomes more critical. Narrow-band injection-locked frequency dividers (ILFD) dissipate a fraction of the energy stored in the tank, which is determined by the quality factor, Q, of the resonator, in every cycle. Therefore, they have fundamentally lower power dissipation than wide-band dividers. Due to their narrow-band nature, ILFDs work in a limited frequency range (locking range). In this paper, shunt-peaking is used as an approach to increase the locking range and lower the power dissipation at higher frequencies.", "doi": "10.1109/ISSCC.2001.912698", "isbn": "0-7803-6608-5", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2001-02", "pages": "412-413, 471" }, { "id": "authors:mehst-6sc27", "collection": "authors", "collection_id": "mehst-6sc27", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111117-115945405", "type": "book_section", "title": "Noise in Phase-Locked Loops [Invited]", "book_title": "2001 Southwest Symposium on Mixed Signal Design", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Jitter and phase noise properties of phase-locked loops (PLL) are analyzed, identifying various forms of jitter and phase noise in PLLs. The effects of different building blocks on the jitter and phase noise performance of PLLs are demonstrated through a parallel analytical and graphical treatment of noise evolution in the phase-locked loop.", "doi": "10.1109/SSMSD.2001.914927", "isbn": "0-7803-6742-1", "publisher": "IEEE", "place_of_publication": "Piscataway, N.J.", "publication_date": "2001-02", "pages": "1-6" }, { "id": "authors:et33s-jpe50", "collection": "authors", "collection_id": "et33s-jpe50", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:APAcicc01", "type": "book_section", "title": "Capacity limits and matching properties of lateral flux integrated capacitors", "book_title": "Custom Integrated Circuits Conference (CICC '01), San Diego, CA, 6-9 May 2001", "author": [ { "family_name": "Aparicio", "given_name": "R.", "clpid": "Aparicio-R" }, { "family_name": "Hajimiri", "given_name": "A.", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Theoretical limits for the capacitance density of lateral flux and quasi-fractal capacitors are calculated. These limits are used to investigate the efficiency of various capacitive structures such as lateral flux and quasi-fractal structures. This study leads to two new capacitor structures with high lateral field efficiency. Simulation and experimental results demonstrate higher capacity and superior matching properties compared to the standard horizontal parallel plate and previously reported lateral-field capacitors.", "doi": "10.1109/CICC.2001.929803", "isbn": "0 7803 6591 7", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2001", "pages": "365-368" }, { "id": "authors:gxcnr-93n40", "collection": "authors", "collection_id": "gxcnr-93n40", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111205-084201864", "type": "book_section", "title": "Analysis and Design of Silicon Bipolar Distributed Oscillators", "book_title": "2000 Symposium on VSLI Circuits: Digest Technical Papers", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Wu", "given_name": "Hui", "clpid": "Wu-H" } ], "abstract": "A systematic approach to design of silicon bipolar distributed oscillators and voltage-controlled oscillators (VCOs) is presented. The operation of the distributed oscillators is analyzed and the general condition for oscillation is derived, resulting in analytical expressions for the frequency and amplitude of the distributed oscillators. Special attention is paid to transmission line modeling that largely determines the performance of the distributed oscillators. A distributed VCO operating at 12 GHz dissipating 13 mW of power is demonstrated. The VCO has a tuning range of 26% with a phase noise of -104 dBc/Hz at 1 MHz offset from the carrier. A second design shows a 17 GHz bipolar distributed oscillator, which dissipates 9 mW of power.", "doi": "10.1109/VLSIC.2000.852863", "isbn": "0-7803-6310-8", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2000-06", "pages": "102-105" }, { "id": "authors:mjwt6-5e920", "collection": "authors", "collection_id": "mjwt6-5e920", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111205-085511285", "type": "book_section", "title": "Complete noise analysis for CMOS switching mixers via stochastic differential equations", "book_title": "Proceedings of the IEEE 2000 Custom Integrated Circuits Conference", "author": [ { "family_name": "Ham", "given_name": "Donhee", "clpid": "Ham-D" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A complete analysis of noise in CMOS switching mixers using stochastic differential equations (SDE) is presented. The noise figure is calculated using this analysis which takes both cyclostationary noise sources and capacitive high frequency effects into account. The analysis leads to important design implications for mixer design and shows that some commonly-used approximations for mixer noise calculations can be misleading in certain cases even at low frequencies. It is demonstrated that there is an optimum value for the load capacitor leading to minimum noise figure and maximum conversion gain for the mixer", "doi": "10.1109/CICC.2000.852703", "isbn": "0-7803-5810-4", "publisher": "IEEE", "place_of_publication": "Piscataway, N.J.", "publication_date": "2000-05", "pages": "439-442" }, { "id": "authors:3sxgj-v0317", "collection": "authors", "collection_id": "3sxgj-v0317", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HUWiscas00", "type": "book_section", "title": "A novel tuning technique for distributed voltage controlled oscillators", "book_title": "IEEE International Symposium on Circuits and Systems, ISCAS 2000 Geneva, 28-31 May 2000", "author": [ { "family_name": "Wu", "given_name": "Hui", "clpid": "Wu-H" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A novel current-steering delay-balanced tuning technique for distributed voltage controlled oscillators (DVCO) is demonstrated. This tuning technique is used to design a DVCO operating at 10 GHz in a 0.35 \u03bcm CMOS technology. The DVCO is continuously tunable between 9.9 and 10.3 GHz. Special attention is paid to the layout issues for the high frequency design.", "doi": "10.1109/ISCAS.2000.855995", "isbn": "0-7803-5482-6", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2000-05", "pages": "57-60" }, { "id": "authors:e6kmx-fv435", "collection": "authors", "collection_id": "e6kmx-fv435", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111207-153428070", "type": "book_section", "title": "Design and optimization of a low noise 2.4 GHz CMOS VCO with integrated LC tank and MOSCAP tuning", "book_title": "ISCAS 2000 Geneva: Proceedings of the 2000 IEEE International Symposium on Circuits and Systems, Emerging technologies for the 21st century", "author": [ { "family_name": "Ham", "given_name": "Donhee", "clpid": "Ham-D" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A 2.4 GHz LC voltage controlled oscillator is designed and optimized via linear programming and implemented in a 0.35 \u03bcm RF BiCMOS process technology. Our design methodology provides an insight to choosing design variables given several constraints such as voltage swing, tuning range and start-up condition. The on-chip spiral inductors used are modeled and optimized by a 3D inductor simulator. The inversion mode MOSCAP tuning is used to achieve 26% of tuning range. The measured phase noise is -121 dBc/Hz, -117 dBc/Hz and -115 dBc/Hz at 600 kHz offset from 1.91 GHz, 2.03 GHz and 2.60 GHz carriers, respectively. The VCO dissipates only 4 mA from a 2.5 V supply voltage", "doi": "10.1109/ISCAS.2000.857097", "isbn": "0-7803-5482-6", "publisher": "IEEE", "place_of_publication": "Piscataway, N.J.", "publication_date": "2000-05", "pages": "331-334" }, { "id": "authors:xrh0s-qpg65", "collection": "authors", "collection_id": "xrh0s-qpg65", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111130-143135860", "type": "book_section", "title": "Design of a novel low-power 4th-order 1.7 GHz CMOS frequency synthesizer for DCS-1800", "book_title": "Proceedings the 2000 IEEE International Symposium on Circuits and Systems", "author": [ { "family_name": "Lehner", "given_name": "Andreas", "clpid": "Lehner-A" }, { "family_name": "Weigel", "given_name": "Robert", "clpid": "Weigel-R" }, { "family_name": "Sewald", "given_name": "Dieter", "clpid": "Sewald-D" }, { "family_name": "Eichfeld", "given_name": "Herbert", "clpid": "Eichfeld-H" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A low-power fully-integrated type-2 4th-order 1.7 GHz CMOS frequency synthesizer for DCS-1800 application is designed and simulated in a 0.25 \u03bcm process technology. The frequency switching is achieved using a novel architecture exploiting a direct digital synthesis (DDS) device as the frequency reference. The new topology significantly lowers the undesired sideband power due to divider ratio switching by directly shifting the frequency of the DDS reference. The frequency synthesizer (excluding the DDS device) dissipates only 9 mW of power from a 2 V power supply. It employs a fast-switching novel charge pump circuit and a low-noise fully-integrated differential LC voltage controlled oscillator using on-chip spiral inductors and accumulation-mode capacitors to meet the requirements of a DCS-1800 system. A detailed analysis of the phase noise in the 4th order loop is presented.", "doi": "10.1109/ISCAS.2000.857540", "isbn": "0-7803-5482-6", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2000-05", "pages": "637-640" }, { "id": "authors:rx96f-mzt47", "collection": "authors", "collection_id": "rx96f-mzt47", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LEEieeejssc00", "type": "article", "title": "Oscillator phase noise: a tutorial", "author": [ { "family_name": "Lee", "given_name": "Thomas H.", "clpid": "Lee-T-H" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "Linear time-invariant (LTI) phase noise theories provide important qualitative design insights but are limited in their quantitative predictive power. Part of the difficulty is that device noise undergoes multiple frequency translations to become oscillator phase noise. A quantitative understanding of this process requires abandoning the principle of time invariance assumed in most older theories of phase noise. Fortunately, the noise-to-phase transfer function of oscillators is still linear, despite the existence of the nonlinearities necessary for amplitude stabilization. In addition to providing a quantitative reconciliation between theory and measurement, the time-varying phase noise model presented in this tutorial identifies the importance of symmetry in suppressing the upconversion of 1/f noise into close-in phase noise, and provides an explicit appreciation of cyclostationary effects and AM-PM conversion. These insights allow a reinterpretation of why the Colpitts oscillator exhibits good performance, and suggest new oscillator topologies. Tuned LC and ring oscillator circuit examples are presented to reinforce the theoretical considerations developed. Simulation issues and the accommodation of amplitude noise are considered in appendixes.", "doi": "10.1109/4.826814", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2000-03-01", "series_number": "3", "volume": "35", "issue": "3", "pages": "326-336" }, { "id": "authors:a6xyn-rjd88", "collection": "authors", "collection_id": "a6xyn-rjd88", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111212-151657259", "type": "article", "title": "Comments on \"Design issues in CMOS differential LC oscillators\" [and reply]", "author": [ { "family_name": "Wang", "given_name": "HongMo", "clpid": "Wang-H-M" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Lee", "given_name": "Thomas H.", "clpid": "Lee-T-H" } ], "abstract": "For the original paper see ibid., vol. 34, no. 5, p. 717-24 (1999). The commenter points out that the phase noise difference reported in the aforementioned paper appears to have a topological cause, and he presents a simple analysis to show that the difference is 6 dB under otherwise identical conditions. In reply, the authors clarify some points in their original work.", "doi": "10.1109/4.823455", "issn": "0018-9200", "publisher": "IEEE", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "2000-02", "series_number": "2", "volume": "35", "issue": "2", "pages": "286-287" }, { "id": "authors:9wzfr-av928", "collection": "authors", "collection_id": "9wzfr-av928", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:WUHcicc00", "type": "book_section", "title": "A 10 GHz CMOS distributed voltage controlled oscillator", "book_title": "Proceedings of the IEEE 2000 Custom Integrated Circuits Conference, Caribe Royale Resort Suites, May 21-24, 2000, Orlando, Florida", "author": [ { "family_name": "Wu", "given_name": "Hui", "clpid": "Wu-H" }, { "family_name": "Hajimiri", "given_name": "A.", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "abstract": "A 10 GHz CMOS distributed voltage controlled oscillator (DVCO) is designed in a 0.35 \u03bcm BiCMOS process technology using only CMOS transistors. The oscillator achieves a tuning range of 12% (9.3 GHz to 10.5 GHz) and a phase noise of -114 dBc/Hz at 1 MHz offset from a carrier frequency of 10.2 GHz. The VCO uses two different simultaneous tuning techniques which allow for a coarse and fine tuning of frequency in a frequency synthesizer. The oscillator provides an output power of -7 dBm without any buffering, drawing 14 mA of DC current from a 2.5 V power supply.", "doi": "10.1109/CICC.2000.852735", "isbn": "0-7803-5809-0", "publisher": "IEEE", "place_of_publication": "Los Alamitos, CA", "publication_date": "2000", "pages": "581-584" }, { "id": "authors:12zyh-syk09", "collection": "authors", "collection_id": "12zyh-syk09", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120109-142808239", "type": "book_section", "title": "Design and optimization of LC oscillators", "book_title": "1999 IEEE/ACM International Conference on Computer-Aided Design, Digest of Technical Papers", "author": [ { "family_name": "del Mar Hershenson", "given_name": "Maria", "clpid": "del-Mar-Hershenson-M" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Mohan", "given_name": "Sunderarajan S.", "clpid": "Mohan-S-S" }, { "family_name": "Boyd", "given_name": "Stephen P.", "clpid": "Boyd-S-P" }, { "family_name": "Lee", "given_name": "Thomas H.", "clpid": "Lee-T-H" } ], "abstract": "We present a method for optimizing and automating component\nand transistor sizing for CMOS LC oscillators. We observe\nthat the performance measures can be formulated as posynomial functions of the design variables. As a result, the LC oscillator design problems can be posed as a geometric program, a special type of optimization problem for which very efficient global optimization methods have recently been developed. The synthesis method is therefore fast, and determines the globally optimal design; in particular the final solution is completely independent\nof the starting point (which can even be infeasible),\nand infeasible specifications are unambiguously detected. We\ncan rapidly compute globally optimal trade-off curves between competing objectives such as phase noise and power.", "doi": "10.1109/ICCAD.1999.810623", "isbn": "0-7803-5832-5", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "1999-11", "pages": "65-69" }, { "id": "authors:1hw2y-5p770", "collection": "authors", "collection_id": "1hw2y-5p770", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HAJieeejssc99a", "type": "article", "title": "Jitter and phase noise in ring oscillators", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Limotyrakis", "given_name": "Sotirios", "clpid": "Limotyrakis-S" }, { "family_name": "Lee", "given_name": "Thomas H.", "clpid": "Lee-T-H" } ], "abstract": "A companion analysis of clock jitter and phase noise of single-ended and differential ring oscillators is presented. The impulse sensitivity functions are used to derive expressions for the jitter and phase noise of ring oscillators. The effect of the number of stages, power dissipation, frequency of oscillation, and short-channel effects on the jitter and phase noise of ring oscillators is analyzed. Jitter and phase noise due to substrate and supply noise is discussed, and the effect of symmetry on the upconversion of 1/f noise is demonstrated. Several new design insights are given for low jitter/phase-noise design. Good agreement between theory and measurements is observed.", "doi": "10.1109/4.766813", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "1999-06-01", "series_number": "6", "volume": "34", "issue": "6", "pages": "790-804" }, { "id": "authors:cx5j0-4p583", "collection": "authors", "collection_id": "cx5j0-4p583", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HAJieeejssc99b", "type": "article", "title": "Design issues in CMOS differential LC oscillators", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Lee", "given_name": "Thomas H.", "clpid": "Lee-T-H" } ], "abstract": "An analysis of phase noise in differential cross-coupled inductance-capacitance (LC) oscillators is presented. The effect of tail current and tank power dissipation on the voltage amplitude is shown. Various noise sources in the complementary cross-coupled pair are identified, and their effect on phase noise is analyzed. The predictions are in good agreement with measurements over a large range of tail currents and supply voltages. A 1.8 GHz LC oscillator with a phase noise of -121 dBc/Hz at 600 kHz is demonstrated, dissipating 6 mW of power using on-chip spiral inductors.", "doi": "10.1109/4.760384", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "1999-05-01", "series_number": "5", "volume": "34", "issue": "5", "pages": "717-724" }, { "id": "authors:8f4yr-hza08", "collection": "authors", "collection_id": "8f4yr-hza08", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SAMieeejssc98", "type": "article", "title": "Fractal capacitors", "author": [ { "family_name": "Samavati", "given_name": "Hirad", "clpid": "Samavati-H" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Shahani", "given_name": "Arvin R.", "clpid": "Shahani-A-R" }, { "family_name": "Nasserbakht", "given_name": "Gitty N.", "clpid": "Nasserbakht-G-N" }, { "family_name": "Lee", "given_name": "Thomas H.", "clpid": "Lee-T-H" } ], "abstract": "A linear capacitor structure using fractal geometries is described. This capacitor exploits both lateral and vertical electric fields to increase the capacitance per unit area. Compared to standard parallel-plate capacitors, the parasitic bottom-plate capacitance is reduced. Unlike conventional metal-to-metal capacitors, the capacitance density increases with technology scaling. A classic fractal structure is implemented with 0.6-\u03bcm metal spacing, and a factor of 2.3 increase in the capacitance per unit area is observed. It is shown that capacitance boost factors in excess of ten may be possible as technology continues to scale. A computer-aided-design tool to automatically generate and analyze custom fractal layouts has been developed.", "doi": "10.1109/4.735545", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "1998-12-01", "series_number": "12", "volume": "33", "issue": "12", "pages": "2035-2041" }, { "id": "authors:vnkez-64739", "collection": "authors", "collection_id": "vnkez-64739", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120112-110510751", "type": "book_section", "title": "Phase noise in CMOS differential LC oscillators", "book_title": "1998 Symposium on VLSI Circuits: digest of technical papers", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Lee", "given_name": "Thomas H.", "clpid": "Lee-T-H" } ], "abstract": "An analysis of phase noise in differential cross-coupled tuned tank voltage controlled oscillators is presented. The effect of active device noise sources as well as the noise due to the passive elements are taken into account. The predictions are in good agreement with the measurements for different tail currents and supply voltages. The effect of the complementary cross-coupled pair is analyzed and verified experimentally. A 1.8 GHz LC oscillator with a phase noise of -121 dBc/Hz at 600 kHz is demonstrated, dissipating 6 mW of power using spiral inductors.", "doi": "10.1109/VLSIC.1998.687999", "isbn": "0-7803-4766-8", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "1998-06", "pages": "48-51" }, { "id": "authors:r1rcw-5sh37", "collection": "authors", "collection_id": "r1rcw-5sh37", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111222-111025211", "type": "book_section", "title": "Phase noise in multi-gigahertz CMOS ring oscillators", "book_title": "Proceedings of the IEEE 1998 Custom Integrated Circuits Conference", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Limotyrakis", "given_name": "Sotirios", "clpid": "Limotyrakis-S" }, { "family_name": "Lee", "given_name": "Thomas H.", "clpid": "Lee-T-H" } ], "abstract": "An analysis of the phase noise in differential and single-ended ring oscillators using a time-variant model is presented. An expression for the RMS value of the impulse sensitivity function (ISF) is derived. A closed-form equation for phase noise of ring oscillators is calculated and a lower limit on the phase noise of ring oscillators is shown. Phase noise measurements of oscillators running up to 5.5 GHz are in good agreement with the theory.", "doi": "10.1109/CICC.1998.694905", "isbn": "0-7803-4292-5", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "1998-05", "pages": "49-52" }, { "id": "authors:pjrjt-sdg61", "collection": "authors", "collection_id": "pjrjt-sdg61", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111220-140652487", "type": "book_section", "title": "Design issues in cross-coupled inverter sense amplifier", "book_title": "Proceedings of the 1998 IEEE International Symposium on Circuits and Systems", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Heald", "given_name": "Raymond", "clpid": "Heald-R" } ], "abstract": "This paper presents an analytical approach to the design of CMOS cross-coupled inverter sense amplifiers. The effects of the equilibrating transistors and the tail current source on the speed of the sense amplifier are analyzed. An analysis of the offset due to mismatch in various parameters is performed, showing that a complete offset analysis has to account for the cell and bitline structure. A new figure of merit for the offset in the sense amplifier and several new design insights are introduced.", "doi": "10.1109/ISCAS.1998.706863", "isbn": "0-7803-4455-3", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "1998-05", "pages": "149 -152" }, { "id": "authors:72n2x-60h85", "collection": "authors", "collection_id": "72n2x-60h85", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120117-110114752", "type": "book_section", "title": "Fractal capacitors", "book_title": "1998 IEEE International Solid-State Circuits Conference: Digest of Technical Papers", "author": [ { "family_name": "Samavati", "given_name": "Hirad", "clpid": "Samavati-H" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Shahani", "given_name": "Arvin", "clpid": "Shahani-A" }, { "family_name": "Nasserbakht", "given_name": "Gitty", "clpid": "Nasserbakht-G" }, { "family_name": "Lee", "given_name": "Thomas", "clpid": "Lee-T" } ], "abstract": "This paper introduces a high-density linear capacitor structure with low bottom-plate parasitics. The density of such a structure improves as process technologies scale. Fractal capacitors retain the linearity of metal-to-metal capacitors with limited degradation of Q. The structures automatically limit the length of the thin metal sections to a few microns, keeping the series resistance reasonably small. Another advantage is the reduction of bottom-plate capacitance because of the smaller area.", "doi": "10.1109/ISSCC.1998.672459", "isbn": "0-7803-4344-1", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "1998-02", "pages": "256-257" }, { "id": "authors:r11pe-dnn76", "collection": "authors", "collection_id": "r11pe-dnn76", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HAJieeejssc98", "type": "article", "title": "A general theory of phase noise in electrical oscillators", "author": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Lee", "given_name": "Thomas H.", "clpid": "Lee-T-H" } ], "abstract": "A general model is introduced which is capable of making accurate, quantitative predictions about the phase noise of different types of electrical oscillators by acknowledging the true periodically time-varying nature of all oscillators. This new approach also elucidates several previously unknown design criteria for reducing close-in phase noise by identifying the mechanisms by which intrinsic device noise and external noise sources contribute to the total phase noise. In particular, it explains the details of how 1/f noise in a device upconverts into close-in phase noise and identifies methods to suppress this upconversion. The theory also naturally accommodates cyclostationary noise sources, leading to additional important design insights. The model reduces to previously available phase noise models as special cases. Excellent agreement among theory, simulations, and measurements is observed.", "doi": "10.1109/4.658619", "issn": "0018-9200", "publisher": "IEEE Journal of Solid-State Circuits", "publication": "IEEE Journal of Solid-State Circuits", "publication_date": "1998-02", "series_number": "2", "volume": "33", "issue": "2", "pages": "179-194" }, { "id": "authors:1rs3z-5xm42", "collection": "authors", "collection_id": "1rs3z-5xm42", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120125-112220383", "type": "book_section", "title": "Level-locked loop: a technique for broadband quadrature signal generation", "book_title": "Proceedings of the IEEE 1997 Custom Integrated Circuits Conference", "author": [ { "family_name": "Navid", "given_name": "Saeed", "clpid": "Navid-S" }, { "family_name": "Behbahani", "given_name": "Farbod", "clpid": "Behbahani-F" }, { "family_name": "Fotowat", "given_name": "Ali", "clpid": "Fotowat-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Gaethke", "given_name": "Rainer", "clpid": "Gaethke-R" }, { "family_name": "Delurio", "given_name": "Micheal", "clpid": "Delurio-M" } ], "abstract": "A method for precise wideband quadrature signal generation is presented. A divide-by-2 stage forms an adjustable phase quadrature signal generator. Its output phase error is converted to an error signal, which feeds back to the quadrature signal generator through an integrator, to correct the output phase difference. Using this method, a phase accuracy better than 0.5\u00b0 is achieved over 40 MHz to 500 MHz of output frequency without any external tuning. The loop compensates for any circuit and layout mismatches, is not sensitive to distorted input LO signals, and has no inherent high frequency limitation.", "doi": "10.1109/CICC.1997.606656", "isbn": "0-7803-3670-4", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "1997-05", "pages": "411-414" } ]