Analysis of the selective behavior of multilayer lossy dielectric structures with a dielectric grating

The reflection and transmission properties of structures consisting of dielectric multilayers (infinitely long along the y direction), with the index of refraction of one of them varying periodically with distance, are examined. These structures are commonly known as waveguides with a dielectric grating and present frequency selective reflection and transmission characteristics. Based on these properties Bertoni et al. (1989) proposed the use of these structures as dichroic surfaces in the millimeter wave band since in this band the dielectric losses are lower. In the work by Bertoni et al. the analysis considered a periodic layer with a height h/sub p/, having a characteristic cell with a period d, made up of two lossless dielectric slabs with air above and below the periodic layer. It is shown in the present paper that the selective behavior of the structure may be modified by adding dielectric layers above and below the periodic layer. In addition, the effect of dielectric loss is also examined.