A methodological analysis of different formulations for solving inverse electromagnetic problems

The authors present a methodological examination of several formulations developed to solve different kinds of inverse electromagnetic problems. Some general numerical formulations of the inverse problems are presented that are defined regardless of the nature of the specific electromagnetic problem. It is shown that the different approaches can be drawn from these general formulations, according to the specific nature of the electromagnetic problems and according to the purpose of the investigations. The most significant aspects of inverse problems, such as existence, uniqueness, and stability of the solution are discussed in detail together with the applicable regularization techniques