Model SRF-77120910-01 is a low-cost 77-GHz sensor developed by Ducommun Technologies for Doppler speed measurements. The sensor includes a high-performance circularly polarized horn antenna, linear-to-circular-polarization converter, and transmit/receiver (T/R) diplexer. The sensor also includes a balanced mixer and Gunn oscillator. It provides +10-dBm output power at 77 GHz with a 12-deg. 3-dB beamwidth and 9-dB conversion loss. It is available with different beamwidths, with a dual-channel in-phase (I) and quadrature (Q) output, and in frequency-modulated-continuous-wave (FMCW) versions.