Non-Uniform Planar MIMO Array Optimization Criterion in Wavenumber Domain for Aliasing-Free Wideband Near-Field 3D Imaging

Microwave/millimeter-wave imaging is widely desired in various applications, including remote sensing, integrated sensing and communications, security, and biomedical imaging. Sparse MIMO arrays, while cost-effective, often face aliasing artifacts due to spectral distortion in non-uniform sampling. This paper introduces an innovative optimization criterion for non-uniform planar MIMO arrays in the wavenumber domain, aiming at aliasing-free wideband near-field 3D imaging. We propose the wavenumber-range spectrum (WS) of the normal plane wave as a tool to evaluate spectral distortion in near-field non-uniform sampling. This approach utilizes the non-uniform-fast-Fourier-transform-based MIMO range migration algorithm with a modified non-uniform sampling function. Simulations show that the optimized array, with maximum peak sidelobe ratio (PSLR) in the WS, consistently maintains low sidelobe levels (SLL) in the point spread function (PSF) for central and edge targets, and thus achieves aliasing-free imaging.