UC San Diego

The thesis presents advanced circuits in CMOS for microwave and millimeter-wave communications. First, low- noise W-band amplifiers and mW-level 170-200 GHz output doublers in 45-nm Semiconductor-On-Insulator (SOI) CMOS technology are presented. The transistors are modeled using R/C extraction and full electromagnetic modeling. The measured ft of a 30x1-[mu]m transistor is 200-210 GHz at a bias current of 0.3-0.5 mA/[mu]m. A 3-stage W-band amplifier shows a record noise figure of 6.0 dB and a saturated output power of 7.5-8.0 dBm with a power added efficiency of 9%, all at 95 GHz. The G-band balanced doubler results in an output power of 1 mW at 180 GHz. A W -band amplifier/G-band doubler chip is also demonstrated, with a peak output power of 0.5-1 mW at 170-195 GHz and a conversion gain of -2 - -1 dB. This work shows that 45-nm SOI CMOS, built for digital and mixed-signal applications, results in state-of-the-art performance at W-band and G- band. Next, a miniature DC-70 GHz single-pole four-throw (SP4T), 50-70 GHz single-pole double-throw (SPDT), and single-pole four-throw (SP4T) switches built in a low-cost 0.13-[mu]m CMOS process are presented. The DC-70 GHz SP4T switch is based on a series-shunt design with input and output matching circuits. Deep n-well (also called triple- well) CMOS transistors are used to minimize the substrate coupling. Also, deep trench isolation is used between the different ports to minimize the port-to-port coupling. The SP4T results in a measured insertion loss of less than 3.5 dB up to 67 GHz with an isolation of greater than 25 dB. The measured port-to-port coupling is less than 28 dB up to 67 GHz. The measured P1dB and IIP3 are independent of frequency and are 9-10 dBm and 20-21 dBm, respectively. The active chip area is 0.24x0.23 mm². When this work was published, it represented the widest bandwidth SP4T switch in any CMOS technology to-date. The 50-70 GHz single-pole double-throw (SPDT) and single-pole four-throw (SP4T) switches are based on tuned [lambda]/4 designs with output matching networks. High substrate resistance together with deep trenches and isolation moats are used for low insertion loss. The SPDT and SP4T switches result in a measured insertion loss of 2.0 and 2.3 dB at 60 GHz, with an isolation of > 32 dB and > 22 dB, respectively. The measured output port-to-port isolation is > 27 dB for both designs. The P1dB is 13-14 dBm with a measured IIP3 of > 23 dBm for both switches. Both designs have a return loss better than -10 dB at all ports from 50 to 70 GHz. The active chip area is 0.39x0.32 mm² (SPDT) and 0.59x0.45 mm² (SP4T). When this work was published, it presented the lowest loss 60 GHz SPDT and SP4T switches and also the highest isolation SPDT switch in any CMOS technology to- date. In another project, 5-6 GHz 8x8 and Ku-band 4x4 Butler matrices are presented in a 0.13-[mu]m CMOS implementation. The 8x8 design results in an insertion loss of 3.5 dB at 5.5 GHz, with a bandwidth of 5-6 GHz and no power consumption. The chip area is 2.5x1.9 mm² including all pads. The 8x8 matrix is mounted on a Teflon board with 8-antennas, and the measured patterns agree well with theory and show an isolation of > 12 dB at 5-6 GHz. The 4x4 design results in an insertion loss of 2.4 dB at 12 GHz with a bandwidth of 11-13 GHz. The chip area is only 0.85x0.65 mm² including all pads, and the power consumption is 0̃ mA from a 1.5 V power supply. The 4x4 matrix is mounted on a Teflon board with 4-antennas, and the measured patterns agree well with theory and show an isolation of > 11 dB at 11-13 GHz. CMOS Butler matrices are an excellent candidate for MIMO systems, and can also replace small-element phased-array systems for high-gain transceivers. The applications areas are in high data-rate communications. Finally, a contactless, microwave-based gamma ray detector for detecting low-energy gamma ray photons is presented as an appendix. The detection is based on a microwave cavity perturbation method, and uses a reflection-type cavity resonator with a detector-grade CZT crystal. The reflected power from the cavity is measured and this monitors the changes in the photoconductivity of the CZT crystal in the presence of a gamma-ray. A gamma ray detection sensitivity of < 100 keV is achieved at room temperature. The proposed system can be used in homeland security or radioactive material characterization applications