Iterative solution of the electromagnetic inverse scattering problem from the transient scattered field

This paper deals with an iterative approach to solve the electromagnetic inverse scattering problem from single view transient data. The measurement configuration consists in illuminating a two-dimensional scattering system with an electromagnetic transient source and in measuring the time domain response all around the investigated region. The aim is then to determine the electromagnetic properties of the target from the measurements. The problem is formulated in the frequency domain for a large number of frequencies, such that the incident pulse is accurately sampled, rather than in the time domain. The parameters of interest, namely, the relative permittivity and the conductivity profiles, are built up iteratively by minimizing a cost functional involving the discrepancy between the measured scattered fields and those that would be obtained via a forward model. Numerical examples are presented to prove the efficiency of the suggested method and its robustness against noise. The influence of the central frequency and of the bandwidth of the incident field on the achievable performances is also illustrated.