Adaptive sidelobe nulling using a reconfigurable mesh reflector antenna

In many scenarios it is useful for an antenna system to possess the ability to respond to sources of intentional or unintentional co-channel interference by autonomously and adaptively forming nulls in its radiation pattern in the direction of these sources. Adaptive nulling techniques for both directly radiating arrays and multibeam array fed reflectors are now relatively mature, with many systems in service. The reconfigurable mesh reflector antenna shown has the capability to shape its pattern in response to user requirements, by control of the shape of the mesh surface. The authors have already shown that the pattern synthesis algorithms generally employed in this capacity may be modified such that in addition to shaping of the high gain region of the pattern, one or more nulls may be formed at prescribed angles, and some results are described. The main limitations of this approach are that a priori knowledge is required of both the required service or coverage area and the locations of the interfering sources, and that substantial computing resources are needed to perform the pattern synthesis. An alternative approach involves the mesh reflector antenna system responding autonomously and adaptively to a source of co-channel interference, by automatically forming a deep null in its pattern in the direction of that source. A technique to allow the latter is the main topic of this paper