Spectral-Domain Analysis of Finite Frequency Selective Surfaces

Though frequency selective surfaces have been investigated for over two hundred years, accurate numerical analysis of these surfaces is still in its infancy. In this thesis, the method of moments is applied in the spectral domain to model finite frequency selective surfaces, to study the effects of non-plane- wave sources, and to explore the advantages of gradually adjusting the lattice and shape of the element in a nonuniform frequency selective surface for non- plane-wave excitation. In pursuing these goals, the following topics are discussed in some detail. Because of the limited interest in free-standing surfaces, and because the usual cascade approach is not applicable to finite frequency selective surfaces, a general multilayer Greens function is developed in order to incorporate an arbitrary dielectric support. Because the analysis of finite arrays can be computationally intensive, several strategies are discussed for efficiently filling the matrices generated by the application of the spectral-domain method of moments. A few methods for handling the singularities of the spectral Greens function are briefly mentioned, including a comparison of several adaptive numerical integration routines for integrating functions which are singular or sharply peaked. The effects of finite dimensions are evaluated by comparing the induced currents and reflection coefficients for the finite and periodic arrays. Keywords Truncated FSS Radar scattering.