Physics-based EM models in support of through-wall microwave imaging

This paper reviews some recent physics-based modeling approaches in support of microwave through-wall building tomography. Building layout estimation is a nonlinear inverse problem with a large number of degrees of freedom (geometry, location, and scattering properties of major building elements, such as walls, floors, and ceilings, plus many other smaller elements such as windows, doorways, and stairways). The physics of microwave propagation will be described, involving multiple reflection, transmission, and diffraction events, which must be accounted for in the creation of a high fidelity, numerically efficient forward model. Through sensitivity tests and, ultimately, comparison with experimental data, these models allow one to quantify some of the fundamental limits that the signal complexity places on building interior estimation.