Multipath Exploitation in Highly Reflective Environments for Enhanced Microwave Imaging via Inverse Source Reconstruction

Multipath effects significantly influence the quality of microwave imaging in highly reflective environments, while the physical measurement aperture size constrains resolution. It is shown that by exploiting multipath reflections, improved resolution can be achieved while maintaining acceptable artifact levels. Based on image theory, strong scattered fields from an ideal reflection plane can be represented by virtual image sources. Using a single-frequency inverse source solver, the spatially distributed original and image sources are reconstructed and separated, which allows separate application of the imaging algorithm for both of them. The coherent combination of both sets of sources together with appropriate phase correction results in an effective aperture expansion that yields superior resolution. Furthermore, this separation strategy significantly mitigates interference artifacts. Simulation results, supported by theoretical analysis and comparison with a ray-tracing enhanced backprojection algorithm are presented to verify the effectiveness of the proposed approach.