Grating Lobe Suppression in Near Range MIMO Array Imaging Using Zero Migration

In near-range sparse multiple-input multiple-output (MIMO) array imaging, since grating lobes spread wide and overlap with each other, the grating lobes and the zeros of the transmitting and receiving array cannot cancel each other out. As a result, there are residual grating lobes in imaging results. This article proposes a grating lobe suppression method based on zero migration and multiapodization. The method is equivalent to broadening the zeros of the array. Therefore, the grating lobes are completely suppressed without increasing the redundancy in the array. To realize the zero migration, a novel imaging method named generalized matched filtering is proposed, which can be implemented by an extended backprojection algorithm. For a sparse periodic array (SPA) designed based on the effective aperture concept, the proposed method can further reduce the number of transceivers while suppressing the grating lobes. Both simulated data and measured data verify its performance.