UC Santa Barbara

Wireless systems for sensing and communication networks are under increasing demand to provide the fusion of radar and radio into a single hardware platform to cooperatively take advantage of the wide spectrum availability in the frequency bands from 100 GHz - 300 GHz. The cooperation enhances communication by spatial localization and improves radar by distributed coordination in dynamic channel environments with an MIMO system. However, the power consumption of transmit and receive arrays increases at higher frequency and becomes prohibitive in mobile applications where the power budget is limiting. Because wireless environments are dynamic, there is potential to save power in advantageous conditions to enable these systems. First, we present circuit techniques for frequency multiplication that enable dynamic reduction of power in the LO chain to improve energy efficiency in array receivers. This is in contrast with conventional receiver arrays using a single LO power and system power consumption for a specific condition. We present a G-band frequency doubler in 90-nm SiGe BiCMOS technology with a novel bias feedback adaptation. This technique linearizes gain and improves controllability of the frequency doubler’s output power with no penalty in power consumption, area, or output power. Second, the technique applied to a fourth subharmonic D-band downconverter in 90-nm SiGe is presented, showing tradeoffs of downconversion performance against power consumption through LO power. Third, LNA designs in 35-nm InP HEMT for heterogeneous integration and 90-nm SiGe BiCMOS for monolithic array integration are presented, with exploration of noise measure as a metric to optimally extract transistor performance. Finally, we present a 4-element IQ receiver array in 90-nm SiGe packaged as a module with wideband dual slotted patch antennas to exhibit application of the bias feedback technique in adapting receiver power consumption to varying FMCW radar sensing conditions. In over-the-air experiments, the module exhibits reconfigurability along a SNR-to-power cost for varying target detection, highly supporting the use of bias feedback adaptation for varying LO power in applications of joint radar and radio systems in highly dynamic environments.