Array signal processing using digital subarrays

Subarrays constitute a step in the direction towards full digitisation of array antennas. An overview of the problems of digital processing with subarray outputs and a description of several mitigation techniques is given. We present rules for designing subarrays, for forming sum and difference beams, clusters of scanned beams at subarray level, and for forming a guard channel. The grating effects of subarrays on adaptive beamforming and STAP are described and demonstrated by examples. Finally we describe the problems of applying superresolution methods with subarrays.