This article presents a 0.88 THz monostatic transceiver in 90-nm SiGe BiCMOS technology with a design based on a combined common-collector harmonic mixer and frequency multiplier topology with an on-chip antenna. The coupler-free monostatic architecture with fourth harmonic mixer and frequency quadrupler avoids a rat race coupler approach and simplifies critical impedance matching problems. The transceiver had -70 dBc/Hz measured phase noise at 1 MHz offset with an 18.5 GHz input signal, -30 dBm EIRP and a minimum SSB noise figure of 57 dB. The transceiver is compatible with an external lens for applications that include imaging and radar.