The Role of Multipath Propagation in Indoor Single-Frequency RF Imaging

This paper addresses the single-frequency radio frequency imaging in the presence of multipath propagation, relevant to indoor sensing applications. The imaging is tackled in a 2-D scenario and formulated as a linearized electromagnetic inverse scattering problem under the Born approximation. Analytical ray-based and full-wave numerical models are exploited to evaluate the incident field and the Green’s function, which are the key quantities for the kernel of the relevant scattering integral equation. The inverse problem is regularized via Truncated Singular Value Decomposition (TSVD). The main goal of this work is to provide a theoretical analysis about how multipath, characterizing indoor signal propagation, affects the imaging performance. In particular, we focus on the analysis in terms of the retrievable spectral content of the unknown contrast function and regularized point spread function. Numerical results highlight the role of multipath information as well as the challenges towards the achievement of a reliable target imaging.