This paper presents a 210-GHz transceiver with OOK modulation in a 32-nm SOI CMOS process (fT/fmax= 250/320 GHz). The transmitter (TX) employs a 2 × 2 spatial combining array consisting of a double-stacked cross-coupled voltage controlled oscillator (VCO) at 210 GHz with an on-off-keying (OOK) modulator, a power amplifier (PA) driver, a novel balun-based differential power distribution network, four PAs, and an on-chip 2 × 2 dipole antenna array. The noncoherent receiver (RX) utilizes a direct detection architecture consisting of an on-chip antenna, a low-noise amplifier (LNA), and a power detector. The VCO generates measured -13.5-dBm output power, and the PA shows a measured 15-dB gain and 4.6-dBm Psat. The LNA exhibits a measured in-band gain of 18 dB and minimum in-band noise figure (NF) of 11 dB. The TX achieves an EIRP of 5.13 dBm at 10 dB back-off from saturated power. It achieves an estimated EIRP of 15.2 dBm when the PAs are fully driven. This is the first demonstration of a fundamental frequency CMOS transceiver at the 200-GHz frequency range.