A 0.48-THz Fully-Differential FMCW Radar Transceiver in 90-nm SiGe BiCMOS

A 0.48-THz fully-differential quasi-monostatic frequency-modulated continuous-wave (FMCW) radar transceiver was designed in a 90-nm SiGe bipolar CMOS technology with $f_{T}/f_{\max}$ of 300/480 GHz, occupying 2.84 m$\mathrm{m}^{2}$ of chip area. The signal generation at 0.48 THz is accomplished using a multiply-by-24 multiplier chain, with two 0.48-THz push-push doublers driven in quadrature for a differential output signal. The differential subharmonic receiver mixer uses a stacked quad topology with measurements revealing a system conversion gain of 7 dB and a single-sideband noise figure of 25.2 dB at 0.471 THz as well as an effective isotropic radiated power of up to -8.8dBm at the transmitter at 0.47 THz. The transceiver is verified in an FMCW radar measurement using an on-board frequency source of a 5.5$\times$ 8.5c$\mathrm{m}^{2}$ demonstrator at a bandwidth of 60 GHz.