A 210–270-GHz Circularly Polarized FMCW Radar With a Single-Lens-Coupled SiGe HBT Chip

A complete circularly polarized 210-270-GHz frequency-modulated continuous-wave radar with a monostatic homodyne architecture is presented. It consists of a highly integrated radio-frequency transceiver module, an in-house developed linear-frequency chirp generator, and a data acquisition chain. The radar front end featuring a fundamentally operated ×16 multiplier-chain architecture is realized as a single chip in 0.13-μm SiGe heterojunction bipolar transistor technology with a lens-coupled circularly polarized on-chip antenna and wire-bonded on a low-cost printed circuit board. In combination with a 9-mm-diameter silicon lens, the module achieves an average in-band directivity of 26.6 dB. The measured peak radiated power from the packaged radar module is +5 dBm and the noise figure is 21 dB. For a 60-GHz frequency sweep, the radar achieves a range resolution of 2.57 mm after calibration, which is close to the theoretical bandwidth-limited resolution of 2.5 mm. With a simple scanning optical setup, this paper further demonstrates the 3-D imaging capability of the radar for detection of hidden objects with a remarkable dynamic range of around 50 dB.