Accurate Microwave Near-Field Imaging of Multiple High-Order Scattering Objects Using Iterative Tracing Algorithm

Conventional microwave imaging algorithms excel in scenarios involving only single scattering, but often encounter imaging artifacts when processing higher order scattering. Previous studies have demonstrated the possibility for accurate imaging of higher order scattering fields in typical planar concave objects. However, these algorithms still encounter difficulties when applied to curved objects with unfixed reflection planes. To solve this problem, we propose an iterative tracing algorithm to establish the forward propagation model of the curved objects. Then an iterative reconstruction method is introduced to automatically separate the scattered fields of each order and accurately reconstruct the target by compensating for both amplitude and phase using the forward model. The illumination areas on the target for different high-order scattering components are further quantitatively analyzed using the proposed forward model. We compare our proposed method with the state-of-the-art imaging algorithms in terms of computational complexity and imaging accuracy. Numerical simulations and experiments are performed to validate the effectiveness of our algorithm.