A novel adaptive wideband frequency invariant beamforming algorithm for conformal arrays

Aiming to solve the difficulty involved in wideband beamforming for conformal arrays, a novel adaptive frequency invariant beamforming algorithm is proposed in this paper. In this algorithm, the pre-steering delays of the traditional Frost beamformer are firstly removed by utilizing a new constraint matrix, which also incorporates the element patterns into the adaptive algorithm. Then, the interference-plus-noise covariance matrix is reconstructed to solve the desired signal contamination problem. Finally, the spatial response variation constraint is introduced to achieve the frequency invariant beampattern. Simulation results using a cylindrical array demonstrate the effectiveness and robustness of the proposed algorithm and prove that this algorithm can achieve superior performance over the existing wideband beamforming methods for conformal arrays.