Caustic-Matching: A New Technique for Improving Limited-Scan Antennas

: Reflector antennas designed with the aid of a technique by which the caustics of the subreflector are matched to those of the main reflector are shown to have the improved limited-sector-scanning capabilities. The matching is achieved over angular scanning sectors of interest by positioning and shaping subreflectors for parabolic cylinder and paraboloidal antennas. The important applications are in the traffic control radars and satellite communications where a small-aperture subreflector can be illuminated by a plane-wave source such as a small phased array, resulting in high-grain limited-scan beam-steering on a large-aperture reflector.