An alternative structure for adaptive broadband beamforming with imperfect arrays

Abstract

A linearly constrained adaptive beamformer, under certain strategies, is hypersensitive to array imperfections when the input SNR exceeds a certain threshold. Due to array imperfections, the desired signal does not fall exactly in the constrained look direction, and then it is canceled out as an interference. To tackle this problem, this paper proposes an alternative structure for the adaptive broadband beamforming system that may obtain a broader beamwidth in the look direction without imposing any derivative constraint on the adaptive processor. The simulation results illustrate that the proposed adaptive beamformer performs with a better response to array imperfections than the conventional Frost beamformer, because the former may broaden the beamwidth in the look direction to concede greater perturbations without the corresponding array rejection of the desired signal.