Design of MIMO Planar Sparse Array and Improved Back-Projection Algorithm for High-Performance 3-D Microwave Imaging

A novel two-step iterative optimization method could be used in microwave and mm-wave bands for optimal topology of 2-D sparse multiple-input multiple-output (MIMO) arrays, and an improved back-projection algorithm (IBPA) for near-range scenarios has been proposed to achieve high-resolution 3-D imaging. According to point spread functions (PSFs), the array topology results from the proposed design method have superior performance on sidelobe level both in the interference region (IR) and non-IR (NIR), and the obtained peak sidelobe levels (PSLs) are lower than the conventional topologies over 2 dB. The IBPA has weighting factors incorporated into its forward physical wave equations to improve accuracy of the model. The imaging capabilities of the proposed array and IBPA have been experimentally verified. The proposed array could further mitigate the artifact distribution in target image than conventional arrays which is consistent to theoretical analysis. The proposed IBPA could provide higher resolution and lower PSLs without increasing the computational complexity.