Amirreza Safaripour
California Institute of Technology
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Featured researches published by Amirreza Safaripour.
IEEE Transactions on Microwave Theory and Techniques | 2016
Amirreza Safaripour; Steven M. Bowers; Kaushik Dasgupta; Ali Hajimiri
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 × 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 ° to 180 ° with tunable axial ratio down to 1.2 dB to achieve circular polarization and the ability to steer the radiated beam up to 15 ° in both dimensions.
IEEE Transactions on Microwave Theory and Techniques | 2015
Steven M. Bowers; Amirreza Safaripour; Ali Hajimiri
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 radiators 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.
IEEE Microwave and Wireless Components Letters | 2016
Dristy Parveg; Mikko Varonen; Pekka Kangaslahti; Amirreza Safaripour; Ali Hajimiri; Tero Tikka; T. Gaier; Kari Halonen
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 mixers 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 mm2 including probing pads.
radio frequency integrated circuits symposium | 2014
Steven M. Bowers; Amirreza Safaripour; Ali Hajimiri
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 2×1 DPC multi-port driven radiator array with beam steering radiates linear polarization across the full polarization angle range of 0° to 180° 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.
radio frequency integrated circuits symposium | 2014
Steven M. Bowers; Amirreza Safaripour; Ali Hajimiri
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.
topical meeting on silicon monolithic integrated circuits in rf systems | 2017
Dristy Parveg; Mikko Varonen; Amirreza Safaripour; Steven M. Bowers; Tero Tikka; Pekka Kangaslahti; T. Gaier; Ali Hajimiri; Kari Halonen
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 mm2.
radio frequency integrated circuits symposium | 2015
Amirreza Safaripour; Steven M. Bowers; Kaushik Dasgupta; Ali Hajimiri
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 2×2 DPC multi-port driven phased array radiates all linear polarizations (0°-180° 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°.
IEEE Journal of Solid-state Circuits | 2015
Steven M. Bowers; Amirreza Safaripour; Ali Hajimiri
Electronics Letters | 2016
Mikko Varonen; Amirreza Safaripour; Dristy Parveg; Pekka Kangaslahti; T. Gaier; Ali Hajimiri
radio frequency integrated circuits symposium | 2018
Amirreza Safaripour; Bahar Asghari; Ali Hajimiri