A 120-GHz FMCW radar frontend demonstrator based on a SiGe chipset

This paper presents a frequency-modulated continuous-wave (FMCW) radar operating at 120 GHz. It was built with Silicon-Germanium (SiGe) chips that employ HBTs with 320 GHz f_max. The chipset comprises a fundamental-wave signal-generation chip with a voltage-controlled oscillator (VCO) that provides frequencies between 114 GHz and 130 GHz and a corresponding dual transceiver (TRX) chip with monostatic and quasi-monostatic TRX cells. The single-stage cascode amplifiers employed in the TRX chip were characterized in separate test chips and yielded peak small-signal gains of approximately 15 dB. Finally, a quasi-monostatic two-channel FMCW radar front end with off-chip differential microstrip-antennas was built on RF substrate. FMCW radar measurements with frequency chirps from 119 GHz to 122 GHz verified the functionality of the designed radar sensor.