Analysis of the Cross-Polarization Performance of Alternative CSC-Squared Doubly Curved Reflector Antenna Geometries Preliminary Results,

A study was initiated to analyze the cross-polarization properties of shaped beam doubly curved reflector types and to identify the design factors that control the cross-polarization level. These design factors were identified as 1 the reflector surface geometry, 2 the feed position, and 3 the feed polarization properties. At present, significant results are only available on the first two factors. The reflector surface geometries examined were threefold 1 the elevation angle strip geometry, 2 the horizontal strip geometry, and 3 the focal point strip geometry. Each strip geometry is formed by an intersecting plane and designed to collimate the rays in the transverse azimuth plane. There are different transforming actions of these reflector geometries on the feed illumination polarization characteristics. In general, vertical polarization produces poorer cross-polarization performance for each of these reflectors than does horizontal polarization. In particular, the focal point strip reflector produces a substantially worse performance than the other two reflector geometries.