A Comparison of Microwave Inverse Scattering and Imaging Techniques

Abstract

Microwave imaging and inverse scattering, although closely related disciplines, have nonethe-less evolved separately over the last few years because of the differences in their respective applications. While both seek to characterize a scattering object (the “target”) from measurements of its scattered field, the methodology used historically to achieve this end differs. Although there is no formal delineation between the two, microwave imaging techniques typically construct a spatial distribution of a field or source-like quantity, such as current, reflectivity, or scattering centers, which is linearly related to the scattered field, but which is often nonliteral and difficult to interpret. Inverse scattering methods, on the other hand, generate reconstructions of the target’s intrinsic characteristics, namely shape and materials properties, which are nonlinearly related to the measured data, and hence require significant computational resources for their implementation. For these reasons, inverse scattering is considered more rigorous and quantitative, while imaging is generally applicable to a wider class of targets, particularly those which are electrically large and complex.