Grating Lobe Performance Improvement of an Arbitrarily Spaced Array of Through-the-wall Imaging Radars Using Time Reversal Techniques

This paper presents a Time Reversal (TR) application to mitigate the grating lobes of an arbitrarily spaced array for a through-the-wall imaging radar (TWIR). Analytical modeling and simulation of array of arbitrarily located elements with (i) conventional and (ii) time reversal beamforming have been carried out. The results are analysed and compared. The array is used to image a target using the multipaths in a typical TWIR environment. The Time Reversal technique as spatial correlator improves the performance of the arbitrarily located array which is akin to the array thinning of conventional array processing. It is demonstrated that the TR beamforming can mitigate the grating lobes of large sparse array with a fewer elements. The performance metrics are captured in terms of Side Lobe Levels (SLLs) and image radius. The SLL performance and image radius are benchmarked for different configurations of array. It is shown that a fewer-element sparse array with Time Reversal is feasible for practical TWIRs.