A 1.42-mm2 0.45–0.49 THz Monostatic FMCW Radar Transceiver in 90-nm SiGe BiCMOS

Terahertz frequency-modulated continuous-wave (FMCW) radars operating close to and beyond $f_{\max}$ often use gain-enhancing lenses to improve the signal-to-noise ratio. A compact single-chip transceiver benefits a lot from the alignment of the lens to the single on-chip antenna in a monostatic system. The typically required coupler for monostatic operation adds an insertion loss. The proposed multiply-by-24 frequency multiplier-based FMCW radar transceiver removes the coupler and integrates both the final 0.48-THz doubler and subharmonic downconverter into a single common collector push–push doubler. The common emitter is the only port at 0.48 THz in this monostatic system, feeding the top-metal on-chip patch antenna using a direct via stack. The 1.42-mm² monostatic FMCW radar transceiver, manufactured in a 90-nm SiGe bipolar CMOS (BiCMOS) technology with an $f_\text{T}$/$f_{\max}$ of 300/480 GHz consumes 85 mA when connected to a 3.3-V supply. At 0.48 THz, the output power is $-$12 dBm and the single-sideband noise figure is measured as 36.3 dB. FMCW radar measurements with operating bandwidths of up to 55 GHz, corresponding to a theoretical range resolution of 2.73 mm are performed using an on-board frequency source of a credit card sized demonstrator.