Efficient time delay compensation at beamforming using subband decomposition for wideband phased array radar

Abstract

For modern phased array radar, wideband system has been developed for the benefits of fine resolution. However, it introduces two main challenges, wideband digital beamforming and wideband adaptive digital beamforming for jamming cancellation. A typical architecture of wideband adaptive digital beamforming consists of time delay compensation using fractional delay filter at baseband followed by subband decomposition and narrowband adaptive digital beamforming. This processing scheme has achieved precise beam steering and good jamming cancellation performance over wideband. In this paper, a novel architecture is proposed by incorporating time delay compensation at digital beamforming in each subband. Without wideband time delay compensation explicitly, different steering vector is applied instead in different subband accordingly, in order to maintain the beam steering accuracy. Additionally, the computation burden is significantly reduced by eliminating the fractional delay filters. Simulation of the typical and novel processing schemes are carried out for comparison. The numerical results show that the novel method can achieve as good performance as the typical method at lower expense of computational throughput, which validates the efficiency of the proposed architecture.