Proposed high-efficiency spherical-reflector antenna

A technique is proposed for raising the efficiency of sphereical-reflector antennas embodying the Gregorian method of phase correction. The method is based on the Galindo-Williams modified Cassegrain antenna. An additional subreflector is introduced between the Gregorian corrector and the spherical reflector, in order to cause the power rom the feed horn to be uniformly distributed over the main reflector aperture. Equations are presented which enable the co-ordinates of the subreflectors to be computed. Two examples are given and a theoretical effieciency of 93% is predicted in one case.