Robust adaptive beamforming for cylindrical conformal arrays with sidelobe suppression

Abstract

Robust adaptive beamforming (RAB) using conformal arrays has recently attracted lots of interest, because they can provide enhanced beam coverage and increased robustness against the mismatch problem. However, the conventional RAB methods for conformal arrays usually cause a high sidelobe level. In this paper, we develop a RAB algorithm for conformal arrays with sidelobe suppression. In this algorithm, we devise an adaptive beamformer with sidelobe suppression using cylindrical uniform conformal arrays. To enhance the robustness of adaptive beamformer, we reconstruct the interference-plus-noise covariance matrix (INCM) by estimating the interference steering vectors (SVs), and formulate a constrained optimization problem to correct the signal-of-interest SV. Moreover, we analyze the influence of penalty factor on the proposed beamformer, and offer the method to find the optimal penalty factor. In contrast to the existing RAB methods, our algorithm achieves higher output signal-to-interference-plus-noise ratio as well as a lower sidelobe level. Numerical results illustrate the superiority of the proposed algorithm over the existing RAB techniques for conformal arrays.