Adaptive beamforming with a focal-fed offset parabolic reflector antenna

The bandwidth and power restrictions on the communications system between a geostationary satellite and a mobile terminal are severe.;This thesis considers the use of an offset reflector with an array feed as a way of combining the high gain of the reflector with the spatial filtering ability of the antenna array. This type of antenna is referred to as a multiple beam antenna (MBA). The question is whether or not adaptive algorithms designed with the direct radiating array structure in mind will work on a multiple beam antenna.;Using the principle of reciprocity and the secondary field of each of the antenna elements in the array the steering vector for the MBA is numerically evaluated.;A special class of adaptive algorithms called cyclic beamforming algorithms are introduced.;The conclusion of this thesis is that adaptive array processing can be performed by using the array as a feed to an offset parabolic reflector. Adaptive algorithms will work on the multiple beam antenna structure without any changes. (Abstract shortened by UMI.)...