Abstract: An antenna feed for a 94 GHz radar combining quasi-optic and microwave integrated circuit (MIC) techniques. The optical components (15-23) couple MIC receive and transmit boards (FIGS. 2, 3 and 4) to the antenna, which may be a steerable cassegrain. Co-polar and cross-polar received signals are coupled out of the optical system by transmitting/reflecting grids (3 and 5) and the transmit signal may be similarly coupled into it (7). The MIC's have antenna patch arrays which are oriented to suit the respective polarization plane and associated grid. The use of a Faraday rotator (17) in conjunction with a grid (5) in the optic path permits spearation of the transmit path (13) from the receive path (25), each then having it own MIC (FIG. 4 and FIG. 3). Alternatively, duplexing is performed in a common MIC (FIG. 6).