Grating Lobe Suppression for Distributed Digital Subarrays Using Virtual Filling

Abstract

A receiving array processing method is presented that synthesizes the antenna response of a contiguous array from the outputs of physically separated arrays of subarrays. It involves filling the gaps between the subarrays with “virtual” elements, thus forming a contiguous array. Therefore, the synthesized pattern has no grating lobes, and amplitude tapering for sidelobe control can be applied. The contiguous array's response can be duplicated in a number of directions limited by the total number of elements. The directions of interest would normally be those of the desired signals (main beam) and interference or clutter (low sidelobes). The directions of arrival of the signals of interest must first be determined before synthesizing the contiguous array response. The modified matrix pencil method has been extended to handle the problem of multiple subarrays for both single and multiple snapshots. The performance of the synthesis method is examined as a function of signal-to-noise ratio (SNR) per element and various array parameters .