ADAPTIVE NULLING IN HYBRID REFLECTOR ANTENNAS

Hybrid antennas, the combination of a radiating or receiving aperture with an array feed, have been the subject of considerable recent inter est because they offer some of the versatility of phased array antenna s at a much lower cost. Adaptive nulling in hybrid antennas has not re ceived as much attention as other important aspects, such as compensat ion for reflector surface distortion, scanning, pattern calculation, a nd the design of multibeam antennas. In this report we investigate ada ptive nulling in hybrid reflector antennas using the Generalized Sidel obe Canceller algorithm. A general framework is presented for the comp uter simulation of narrow band adaptive nulling in hybrid reflector an tennas that takes account of the details of reflector scattering and p olarization. The general framework is then illustrated by the results of calculations performed for an offset paraboloid with a planar feed located in the focal plane of the paraboloid.