Diffraction shaping of reflector antennas with elliptical apertures and circular feed

Reflector antennas with elliptical apertures are often seen to be advantageous in satellite communications and radar applications. Utilization of an elliptical aperture is typically motivated by the required radiation patterns, and the reduced weight and cost. The central issue in the design of such elliptical reflector antennas is re-distributing or re-directing the feed field to the reflectors in the manner that the desired beam characteristics are obtained. It becomes a challenging task when a more complex radiation pattern such as a contoured-beam is to be generated from an elliptical reflector antenna that uses one circularly symmetric feed. In this situation, the field-redirection can only be achieved through reflector shaping. In the paper, the diffraction shaping technique based on an orthogonal global surface expansion and optimization techniques is employed to shape an elliptical dual-reflector antenna, and the result compared with that using a circular reflector antenna.<>