Implementation of the robust null extension for the SDR DBF of two-dimensional array antenna

Based on software-defined radio (SDR) architecture, 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 realized using the field programmable gate array (FPGA) to improve the interference cancellation capability of the two-dimensional array antennas. The hardware reconfiguration feature of SDR architecture can support multiple modes of the DBF striving for compactness and efficient processing power. The Howells-Applebaum algorithm, eigen value 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.