Design procedure for a steerable gridded spot antenna with low side lobes

Satellite antenna require very tight performance in terms of edge of coverage (EOC) gain, crosspolarisation discrimination (XPD), absolute level of cross polarisation and side lobe mask over the global coverage. A dual "ridded reflector (DGR) antenna is the best compromise between electrical performance and mechanical envelope. It consist of two single reflector (a "ridded front shell and a solid or "ridded rear shell) arranged in offset configuration. The two reflectors are translated along the focal axis and rotated around the aperture centre axis in opposite directions in order to separate the feeds and to deflect the residual cross-polarisation lobes out of the coverage. This paper presents an innovative DGR antenna rear reflector shaping approach developed for a Kuband Steerable Spot Antenna (SSA).