Influence of standing waves on the solution of the inverse problem of reconstructing parameters of a dielectric inclusion in a waveguide

We consider numerical determination of the dielectric media parameters of inclusions in a waveguide of rectangular cross-section from the transmission coefficient. We develop and apply computer codes implementing the FDTD algorithm for numerical solution of the nonstationary Maxwell equations with perfectly matched layer (PML) absorbing boundary conditions using the Berenger layout. We estimate parameter ranges providing the necessary accuracy for solving forward and inverse scattering problems for waveguides with inclusions. Aposteriori estimate of the amplitude of higher-order evanescent waves is obtained and their influence on the choice of parameters of the numerical method is determined.