Control of reflector antennas performance by rim loading

An analysis of the behavior of reflector antennas loaded by a surface impedance along a peripherical rim is carried out in order to ascertain the possibility of improving their performance by such a loading technique. Both single and dual (Cassegrain) reflector antennas are considered. It is shown that an effective control of the radiated field can be achieved by the proper choice of the loading characteristics. In the case of Cassegrain antennas, subreflector loading is sufficient to enhance copolar or crosspolar overall performance.