A Two-Reflector Beam Waveguide Feed for Intelsat-A Ground-Station Antennas with Frequency Reuse Operation

A beamwaveguide feed system for large groundstation antennas composed of only two beam reflectors is described. It is fully capable of 4/6 GHz frequency reuse operations. After discussing the main design principles the RF-properties of the beam waveguide are demonstrated by scale model measurements. The mechanical realization of the original feed components and the essential electrical parameters (gain, radiation patterns, crosspolarization isolation) of a recently completed 32m-Cassegrain-antenna are presented.