Microwave transmission tomography of forward scattering objects

In this paper we derive an approximate high-frequency Green´s function (propagator) for directed waves scattered in an inhomogeneous medium. The analysis is based on a path integral formalism incorporating the ray concept into a full-wave description of the diffraction effects. It is shown that the propagator obtained can be presented in the form of a paired Fresnel transform. The latter is easily invertible, which allows us to use this solution for microwave Radon-type tomographic reconstruction of (lossy) dielectric objects. As a result, the refraction/diffraction artefacts in the recovered image are essentially reduced.