Polarization matching of wide angle conically scanned phased array beams

The scanning of a dually polarized linear phase array outside the cardinal planes of the array results in significant polarization mismatch loss. It is shown here that by using a quasi-optical diplexer to separate the array into two arrays, it is possible to correct for the polarization mismatch by means of properly oriented polarization rotators. The method proposed here is demonstrated for an earth station antenna employing an imaging reflector arrangement fed by a conically scanned linear array feed to track the geosynchronous satellite arc. The method is found to reduce the maximum polarization mismatch loss from 3.6 to 0.008 dB over the entire 12/14 GHz satellite communication band.