Analysis of Scattering Characteristics for Strip Grating Sandwiched between Two Dielectric Layers under Oblique Incidence and Its Applications in Spatial Filters and Circular Polarizers

Abstract

Scattering characteristics of strip grating sandwiched between two dielectric layers in the case of plane-wave arbitrary oblique incidence are carefully investigated by a new method which combines coordinate revolving theory with the rigorous mode matching method. Comparisons between the results obtained with the present method and those given by the other methods verify the effectivity and practicability of the present method. The spatial filter characteristics of the new strip grating structure are given. It shows that the ultra-wideband bandpass characteristics can be realized using the present structure. Besides, a new circular polarizer is proposed. It is indicated that the new circular polarizer can realize complete circular polarization for every frequencies by means of changing the structure parameters of the dielectric uniform layers, which overstep the limitation of single strip that can achieve circular polarization only in a fixed frequency. The present investigation gives some useful guidelines for accurate design of the spatial bandpass filters and circular polarizers.