Efficient robust broadband beamforming using circular antenna arrays

Broadband antenna arrays can suffer significant performance degradation when the array response vector for the desired signal is not known exactly. Diagonal loading of the correlation matrix is a popular technique applied to the beamformer to increase robustness of the array system. This paper presents two robust beamforming algorithms for circular broadband arrays using efficient realization techniques. These techniques do not use presteering, and allow an array designer to arbitrarily specify the main beam look direction and frequency response. The circular array processor is able to scan a beam azimuthally through 3600 with little change in either the beam width or the sidelobe level. Simulation results exhibit enhanced robustness performance of the processor.