This paper presents a frequency-modulated continuous-wave (FMCW) radar operating at 120 GHz, which features silicon–germanium (SiGe) chips that employ HBTs with 320 GHz fmax. The chipset comprises a fundamental-wave signal-generation chip with a voltage-controlled oscillator (VCO) that provides frequencies between 114 and 130 GHz and a corresponding dual–transceiver (TRX) chip that supports monostatic and quasi-monostatic radar configurations. The cascode amplifiers used 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 frontend with on-board differential microstrip antennas was built on an RF substrate. FMCW radar measurements with frequency chirps from 116 to 123 GHz verified the functionality of the designed radar sensor.
