Skip to main content
Open Access Publications from the University of California

UC San Diego

UC San Diego Electronic Theses and Dissertations bannerUC San Diego

SiGe integrated circuits for millimeter-wave imaging and phased arrays


This dissertation presents work in two areas, the first of which is 35-44 GHz power dividers for phased-array transmit systems. A compact active 1:16 single-ended power divider in a 0.18 [mu]m SiGe technology is presented, which achieves 0.8 dB rms gain imbalance and 6⁰ rms phase imbalance at 35 GHz. A second-generation divider is also presented, with 0.3 dB rms gain imbalance and 4⁰ rms phase imbalance at 40.5 GHz. The cascode-node power division approach is shown to be a useful and compact power division topology. A differential broadside-coupled stripline (BCS) structure integrated vertically in the 0.18 [mu]m SiGe interconnect stackup is also developed, which can produce highly symmetric corporate-feed networks (tree structure). A 1:8 power divider is presented which incorporates the BCS structure and attains 0.4 dB rms gain imbalance and 3⁰ rms phase imbalance at 44 GHz. Finally, a sixteen-element 44 GHz beamforming chip with integrated phase shifters utilizing the BCS structure is also presented, and is the first example of a sixteen-element phased-array beamformer at any frequency. The second area of work is in W-Band (70-110 GHz) imaging systems, and several W-band RFICs are developed in the IBM8HP SiGe process (0.12 [mu]m BiCMOS). A wideband 84-100 GHz LNA with 19 dB gain and 8 dB NF is first presented, along with a second-generation LNA achieving 8 dB more gain. An 80- 110 GHz SPDT switch with 2.3 dB insertion loss and 21 dB isolation is developed, and a biased power detector circuit with 14 kV/W responsivity, 40 nV/pHz output noise, and 2.5-3 pW/pHz NEP is presented along with noise and responsivity analysis. These circuits can replace current (and more expensive) III-V chips in many applications. Two passive imaging chips are developed using these RFICs. First, a total-power radiometer is presented (LNA + Detector) which can achieve 0.69 K temperature resolution when 1/f noise contributions are removed by electronic or mechanical chopping. Following this is a Dicke radiometer chip integrating a SPDT, LNA, and W-band detector. This chip can achieve 0.84 K temperature resolution by using electronic chopping, which is comparable to current III-V implementations and is the first SiGe or CMOS W-Band imaging chip. The thesis also contains a summary of the equations required for imaging systems, and an investigation of the additional 1/f noise found in the radiometer chips. The 1/f noise problem is solved using large-area resistors in the bias network layout. The thesis concludes with a presentation of differential SiGe LNA designs and radiometer chips which are designed to be compatible with planar differential antennas

Main Content
For improved accessibility of PDF content, download the file to your device.
Current View