Multi-Resolution Strategies for Microwave Inverse Scattering-Challenges, Solutions, and Future Trends

This work deals with the retrieval of the electromagnetic properties of two-dimensional (2D) and three-dimensional (3D) domains starting from microwave scattered data. Within this context, multi-resolution (MR) methods can yield accurate, robust, and computationally-efficient solutions, overcoming single-resolution (SR) inversion strategies. As a matter of fact, they reduce the degree of non-linearity of the inverse scattering (IS) problem, providing at the same time an effective regularization of its solution. The aim of this work is to (i) highlight the main concepts and principles of MR strategies, (ii) provide an overview of the most recent advances in this field, and (iii) introduce an innovative overconstrained (OC-MR) solution strategy for solving fully non-linear IS problems.