Analysis Of The Electromagnetic Scattering Properties Of Multilayered Frequency Selective Surface Using Generalized Scattering Matrix Theory

Frequency selective surfaces have dichroic properties, they are single layer or multilayer structures, which are comprised periodically by passive resonant elements (patches or apertures). The frequency selective property is own to the reciprocities between periodic structure and microwaves, which exhibits full reflection (patches) or transmission (apertures) in the neighborhood of the element resonant frequency.Generalized scattering matrix theory is base on a spectral domain moment method. To obtain the overall scattering parameters of the structure, which are used to determine the reflection and transmission properties, a matrix of scattering parameters is evaluated for each individual layer, and then a scattering matrix for the entire structure is formed by a procedure analogous to the cascading of networks iteratively. This technique is very appropriate for multilayered periodic structures with arbitrary shape and layer separation.In the paper, the theory of GSM is used to analyze the electromagnetic scattering characteristics of multilayered FSS. And a lot of simulation examples are given to verify the effectiveness of this method. Firstly, based on strip grating and mesh grating, the athletics principles of the electrons in metal which is excited by electromagnetic wave are introduced. As a result, the filter mechanism of FSS can be understood thoroughly. In succession, by analyzing two kinds of basic FSS in free space, spectral method and its expanded application to stratified FSS is recommended, including the establishment of operator formulation, the process of solution of induced current by Galerkin method and acquirement of scattering field. And then, the process of analyzing FSS using GSM, including modeling, analysis and numerical calculation is discussed in detail. Some simulation examples of multilayered FSS are presented, at last. And the effect rules of frequency response with regards to the geometric shape of element, size, the thickness of dielectric substrate, incidence angle. Besides, the convergence of frequency response in view of the number of basis functions and the quantity of Floquet harmonics are discussed. All those numerical results show that GSM is an effective and universal method for the analysis of multilayered FSS.