On the identification of defects in a periodic waveguide from far field data

Abstract : The aim of this paper is to apply the Linear Sampling Method and the Factorization Method to retrieve some defects in a known periodic 2D waveguide from scattering data. More precisely, some far field approximations of these two sampling methods are derived. They amount to consider the so-called propagating Floquet modes as incident waves. The efficiency of the far field formulation of the LSM is shown with the help of some numerical experiments.