Minmax optimization of arrays of rectangular feeds for contoured beam reflector antennas

It is shown that the performance of a contoured-beam reflector antenna in which the feed array consists of rectangular feeds of different sizes can be significantly improved by optimizing the horn aperture geometry and the excitation coefficients simultaneously. An automatic synthesis procedure has been developed in which a minmax algorithm is used to adjust the geometry variables together with the excitation coefficients to maximize the minimum directivity in the coverage. In the example described the minimum directivity has been increased from 28.62 dBi to 29.74 dBi. The procedure has been extended to include simultaneous multicoverage optimizations with orthogonality restrictions in the excitation coefficient sets (dual mode).<>