Shaping of subreflectors in cassegrainian antennas for maximum aperture efficiency

This paper describes a systematic technique for obtaining high aperture efficiency in a Cassegrainian feed system by special shaping of the subreflector. Theoretical expressions are derived that determine the subreflector shape, which gives a uniform illumination of a paraboloid for a given primary feed pattern. Experimental data are then presented, which demonstrate the enhanced performance of a Cassegrainian feed system using a subreflector shaped according to the theoretical expressions.