Sparse MIMO array for short-range imaging

The focusing capability of two dimensional circularly rotating multiple input multiple output (2D-CR-MIMO) array is investigated by taking into consideration the dense sampling, in radial direction, shorter than half wavelength within different media. The impact of the position of the focusing point on the beamwidth and sidelobe structure is also investigated for narrow band and ultra-wideband cases. Within different non/low conductive media, the peak side lobe level does not change dramatically and the large operating frequency band does not play a remarkable role in the maximum side lobe level reduction thanks to the dense sampling in radial direction. As focusing point moving to the edge position, the focusing property of the array becomes worse and the maximum side lobe level rises for both narrowband and ultra-wideband cases.