Study on ADBF for Difference Beam at Subarray Level with Low Sidelobe Level

Optimum difference beamforming at subarray level based on LCMV criterion has an excellent jammer cancellation performance, but compared with the quiescent pattern, sidelobe level of the difference pattern remarkably increases. ADBF for difference beam at subarray level based on subspace projection can yield exactly the desired quiescent pattern in the absence of jammer, but the limitation is that it experiences SINR loss with respect to optimum approach. Thus, we resort to a combination approach which combines the optimum approach and SSP approach. This approach can suppress sidelobe level effectively, while assuring limited SINR loss with respect to the optimum filter.