A fully integrated transceiver operating at 0.38 terahertz (THz) has been demonstrated in 0.13 μm SiGe BiCMOS with fT = 230 GHz. We present a quadrature push-push harmonic circuitry consisting of the clamping pairs driven by balanced quadrature LO signals coupled through the transformers and the Coplanar Stripline (CPS). Harmonic generation of the clamping circuit is analyzed with a clamped sinusoidal model. Several terahertz circuits such as a quadrupler, a THz subharmonic mixer, and an IQ quadrature generator are implemented with the quadrature push-push circuitry to realize a homodyne FMCW radar. Radar functionality is demonstrated with ranging and detection of a target at 10 cm. The measured Equivalent Isotropically Radiated Power (EIRP) of the transmitter is -11 dBm at 0.38 THz and the receiver noise figure (NF) is between 35-38 dB while dissipating a power of 380 mW.