Robust null extension for two-dimensional array antenna

In this paper, a multiple null digital beam former (DBF) that can adjust the number, width and depth of the nulls in accordance with the environment requirements is studied to improve the interference cancellation capability of the two dimensional array antennas. The Howells-Applebaum algorithm, eigenvalue decomposition (EVD) and principal component methods are employed to derive the optimal weighting matrix of the multiple null DBF and simplify the computation of inverse interference covariance matrix, which can be implemented with the parallel processing architecture. If there is no jamming occurred, the DBF returns to its normal beam pattern. Finally, the simulations demonstrate the robustness of the interference cancellation of the multiple null DBF for a 16 by 16 phase array antenna.