Optimal Irregular Subarray Design for Adaptive Jammer Suppression in Phased Array Radar

In phased array radar systems, digital beam forming (DBF) techniques allow implementation of Array Signal Processing (ASP) algorithms like Adaptive Beam Forming (ABF) for jammer cancellation and high resolution angle estimation. In larger phased array radars, for cost and computational benefits, analog subarrays are formed and this output is digitized. For modularity in design and ease of maintenance these analog subarrays are designed with same structure, resulting in grating lobes in the super array antenna pattern. The performance of the system degrades heavily when jammer directions coincide with the grating lobes of the super array pattern. Joint design of subarray configuration and adaptive weights during radar operation using optimization algorithms exist in literature. In this paper, we propose a method which will design the subarray configuration with the required performance constraints and only beamforming weights are computed during the radar operation, for adaptive jammer suppression. This is shown to reduce the computational load enormously in the large phased array radar with acceptable performance, for adaptive jammer suppression. Numerical simulation results are provided to demonstrate the nerformance of the nronosed technique.