Efficient 3-D Imaging Algorithm for Multilayer Dielectrics Based on MIMO-SAR System

Abstract

The millimeter-wave (MMW) multiple-input multiple-output synthetic aperture radar (MIMO-SAR) system is highly valued in nondestructive testing due to its high resolution, robust penetration, and multidimensional data acquisition. Nevertheless, most existing imaging techniques are constrained to free-space or half-space scenarios, which typically leads to spatial blurring and low computational efficiency in multilayered dielectric applications. This study addresses these challenges by proposing an accurate and computationally efficient imaging algorithm for multilayered targets. The algorithm is developed based on a scalar Green’s function formulation for multilayer dielectric media, incorporates transverse-wavenumber continuity conditions at the interfaces, and employs spherical wave decomposition for efficient wavefield expansion. By integrating the fast Fourier transform (FFT) with multilayer phase compensation, the method achieves accurate focusing while maintaining high computational efficiency. Simulation and experimental results confirm that the proposed algorithm achieves comparable imaging quality with significantly improved computational efficiency compared with conventional approaches.