Factorization of the feed efficiency of paraboloids and Cassegrain antennas

The first approximation to the aperture efficiency of a paraboloidal reflector antenna is called the feed efficiency. The factorization of the feed efficiency into subefficiencies which account for losses due to spillover, cross polarization, nonuniform aperture illumination, and phase errors is considered. The relations between the radiation patterns of circularly and linearly polarized feeds are also derived.