Synthesis of offset dual shaped subreflector antennas for control of Cassegrain aperture distributions

Many existing large ground reflector antennas have been designed as Cassegrain systems - i.e., paraboloid/hyperboloid-combinations. Other large ground antennas are simply paraboloid designs. Upgrading the gain of these systems to a gain comparable to that obtainable with a daul shaped reflector antenna system has been an important and costly objective of many such ground stations. A potentially economic method for such an antenna upgrade is presented herein. It involves a redesign of only the subreflector portion of a Cassegrain antenna or the introduction of a subreflector feed system for a paraboloid. A pair of offset subreflectors are synthesized which will give a controllable high gain amplitude distribution in the aperture of the large paraboloid.