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Adaptive Cancellation of
Multiple Mainbeam

Richard M. Davis, Ronald L. Fante, and Thomas P. Guella
The MITRE Corporation
202 Burlington Road
Bedford, MA 01730-1420
email: rmdavis@mitre.org

Abstract Mainbeam jammers offer a serious challenge to a radar system. The usual solution is to place a strobe in the jammer direction, but this effectively blanks two beamwidths of azimuth scan. If many jammers are present, and they are spread in azimuth over several radar beamwidths, detection can be denied over an entire azimuth sector. The authors demonstrate that the problem can be solved using auxiliary antennas separated from the main antenna by distances sufficiently large to enable narrow mulls to be placed on the mainbeam jammers while maintaining peak gain on a desired target. Nulling over very wide bandwidths can be realized by using adaptive FIR filters at the outputs of each auxiliary. A design procedure for the auxiliary array is presented, including the number of required auxiliaries, their gain, spacing, etc. Simulated nulling performance for both sum and difference beams is presented.



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