A lens-coupled 210–270 GHz circularly polarized FMCW radar transceiver module in SiGe technology

A 240 GHz homodyne circularly polarized SiGe FMCW radar transceiver module with a single on-chip antenna is presented. The transceiver chip is implemented in a low-cost 0.13-μm SiGe HBT technology version with cutoff frequencies fT/fmax of 300/450 GHz. The transmit block comprises a wideband ×16 frequency multiplier chain, a 4-stage PA, while the receive block consists of a 3-stage PA acting as a preamplifier with high linearity, a fundamental down-conversion mixer, and a 4-stage PA to drive the mixer. A Gysel power splitter, a coupled line quadrature hybrid coupler, and a dual polarization on-chip antenna are added on-chip to realize a fully integrated radar transceiver. All building blocks are operated differentially. The use of a single antenna in the circularly polarized radar transceiver leads to compact size and high system SNR. The measured peak radiated power from the lens-packaged radar module is +5dBm and the SSB noise figure is 21 dB. The characterization bandwidth of the radar transceiver is 54 GHz around the center frequency of 240 GHz, and the simulated Tx-to-Rx leakage is below -23 dB. After system calibration the range resolution of 2.75mm is achieved, which exactly corresponds to the theoretical BW-limited resolution value.