A hemispheric coverage spherical reflector scanning antenna system

Abstract

The spherical reflector has long been acknowledged for its potential to provide beam scanning from a fixed primary reflecting surface, with no gain loss or pattern distortion over the scan range. This property allows the cost of a scanning antenna system to be reduced, relative to a conventional reflector antenna system, by eliminating the need to move the primary reflector with the appropriate precision, and the need to maintain the primary surface accuracy at all elevation angles. There are applications, such as user terminals for LEO/MEO satellite systems, which require angular coverage over almost the entire upper hemisphere, and which additionally require the ability to use two independent beams. A new spherical reflector antenna design (spherical constellation antenna system, SCAS) has been developed to address these and similar requirements. This system provides 3 independent beams from 3 separate but colocated spherical reflectors, with the beam scanning effected by movement of the 3 feed systems. Various aspects of SCAS are protected under US and international patents.