Decay of electromagnetic energy in a perturbed half-space

In this paper, we consider the scattering properties of a dielectric perturbed half-space situated over a perfectly conducting plane P. We first analyze the influence of a short range perturbation of the physical properties (dielectric and magnetic) of the medium on electromagnetic fields, then we investigate the case when the conducting plane is replaced by an electromagnetic grating, for a suitable polarization of the fields. In these two situations, we give an estimate for the decay of local energy.