The design and development of a 94 GHz wide scan angle lens corrected Cassegrain antenna

Describes the development of an antenna which was subject to the following constraints: (1) The antenna should be capable of scanning the RF beam in both yaw and pitch up to a maximum of 35° compound angle. (2) The antenna should fit within a 55 mm radius cylinder capped with a hemispherical radome. Extensive theoretical and experimental trade studies were carried out to establish the most suitable antenna concept and optimum antenna design for this seeker application. The concept chosen was derived from a class of wide-angle phase-corrected reflectors and utilised a Cassegrain antenna with a body fixed feed and radome mounted subreflector. Beam scanning was achieved by rotating the primary reflector about its vertex and a PTFE lens was fitted to the front surface of the primary to maintain the RF performance over the prescribed 35° beam scan range. The antenna was fed by a corrugated conical monopulse horn