Abstract: To improve the wide-angle scanning properties of the satellite antenna, we concentrate on the shaping of the main reflector of the Side-Fed Offset Cassegrain (SFOC) antenna by the method of the ray tracing and the idea of the optimization. In the process of reflector shaping, in order to enhance the flexibility of the expression for the reflector, a two-dimensional cubic B-spline is used to approach the reflector surface according to the initial data. Then, taking the rays’ paths which are equal from every feed to corresponding apertures as the optimization objective, the interprolation data points for the spline function are adjusted with Powell’s direct method, and in this way, the shaped reflector surface is obtained. The analytical results indicate that the 1-D and 2-D gain degradations of the SFOC antenna due to the aberration are reduced remarkably, and thus the wide-angle scanning properties of the SFOC is improved.

Key words: satellite antenna, ray tracing, reflector shaping, B-spline