Time domain inversion techniques for electromagnetic scattering problems

In English This paper presents a review of and a comparison between two different methods
to solve an inverse scattering problem in the time domain. The problem
is that of propagation of transient electromagnetic waves in spatially inhomogeneous
slabs of finite length. The permittivity and conductivity profiles
are assumed to vary only with depth and the scattering problem is thus onedimensional.
Several algorithms to solve the direct and inverse scattering
problems for continuous and discontinuous permittivity profiles are suggested.
Some of these algorithms have not been published before. The aim of this paper
is to compare and review these methods. More specifically, the numerical
performance of the invariant imbedding approach (layer-stripping)and the
Green functions formulation (downward continuation)is compared. Some
new results based upon time reversal techniques for a lossless slab are presented
in an appendix.