Scattering by double gratings with three layered dielectric slabs

The authors have investigated the scattering properties of an electromagnetic wave by a grating whose structure consists of three dielectric slabs and strips on the upper side of the slabs from the viewpoint of a polarization discriminator. In the analysis, they used the spectral domain method combined with the sampling theorem. They have also studied the grating problem whose structure is asymmetrical and double structured with a dielectric slab in the case of oblique incidence. The method is extended to analyze the problem of an asymmetrical double-structured grating backed with three-layered dielectric slabs. The expressions for the scattered field are obtained by means of the superposition of the results of the single grating case.<>