Enhancing antenna performance through multimode feeds and distribution networks

The low-sidelobe properties of dual or multimode illumination functions characterizing several waveguide types were applied to a variety of antenna applications. The most widespread application of multimode technology has been for the design of high-performance monopulse feed systems for Cassegrain antennas. The combinations of multimode and near-field radiation properties of horn feeds has resulted in further feed performance improvements. Wideband applications of multimode techniques have been demonstrated by minimizing the differential reference-mode phase shift introduced by the feed system.