Discussed in this paper is the nulling performance of a single- and a multiple-aperture multiple-beam antenna (MBA). A linearly constrained minimum power algorithm incorporating both main beam and derivative constraints is formulated and simulated. The nulling resolution of the multiple-aperture MBA is shown to be superior to that of the single-aperture MBA. In addition, a method for illuminating a region in space with constant gain while simultaneously nulling interfering signals within a fractional single element beamwidth of this constant gain region is illustrated. A flat gain pattern is achieved by spacing derivative constraints over the spatial region where the desired signals are known to be transmitting. Derivative constraints are particularly useful when the precise directions of arrival for the desired signals are not available to the beamformer.
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