A Novel Two-Dimensional Sparse MIMO Array Topology for UWB Short-Range Imaging

In this letter, according to the two design principles of uniform distribution and less element shadowing for effective aperture, a novel two-dimensional (2-D) sparse ultrawideband (UWB) multiple-input-multiple-output (MIMO) antenna array topology is optimized and proposed for short-range high-resolution imaging. During the optimization, a "grid method" (GM) is proposed to judge the uniformity of effective aperture, and of which the maximum shadowing number (MSN) is obtained by the projection slice method. Compared to other two different arrays having the same number of transceivers, the proposed optimal array has a better control over the sidelobe level (SL) both in the interference region (IR) and non-interference region (NIR) of the simulated radiation patterns, from which the peak sidelobe levels (PSLs) of the optimal array obtained are lower than the compared ones over 2 dB. Experimental imaging results for a mannequin target also verify the outstanding imaging capability of the proposed array. Therefore, with a small number of effective elements, the proposed array topology has potential applications for high-efficiency UWB short-range imaging.