A High Power Versatile Feed System for Communications Satellite Usage

Abstract

The high power versatile feed system for communications satellite usage is of the three-channel monopulse type capable of simultaneous operation over the receiving frequency band of 3700 to 4200 MHz and the transmitting frequency band of 5925 to 6425 MHz. The feed system provides an on-axis transmit beam for the upper frequency range and three-channel monopulse tracking and receiving outputs for the lower frequency range. These simultaneous transmit and receive functions are orthogonally polarized. The feed system consists of a multi-element aperture array with an associated remote polarization control panel. The system is capable of processing transmitted signals of power levels up to 12 kw for the purpose of satellite command and data transmission. It is also capable of processing the relative azimuth and elevation error signals for satellite tracking. The feed system is suitable for primary focal point excitation of parabolic reflectors (F/D between .45 and .6), and for dual reflector or Cassegrainian systems. The sum and difference mode of operation are precisely controlled with a front aperture to provide the proper illumination functions for the particular reflector systems, thus achieving high system efficiencies and correspondingly high G/T ratios.