Scattering from frequency selective surfaces: an efficient set of V-dipole basis functions

In this paper, a novel set of V-dipole basis functions is introduced. These basis functions are used to approximate the induced surface current density on an infinite, plane frequency selective surface (FSS). The elements of the FSS are supposed to consist of straight sections and bends. Two groups of elements which the present V-dipole basis functions can be applied to are identified, namely, the center connected elements and the loop-type elements. Using the established spectral Galerkin method, where the method of moment (MoM) procedure is carried out in the spectral domain, we determine the reflection and transmission coefficients of the FSS. The convergence of the solution is demonstrated both for existing bases and the present V-dipole basis functions. It is found that the double infinite Floquet sum diverges when existing, discontinuous, basis functions are used, but that convergence is obtained for the present basis functions. Therefore, care needs to be exercised, and it would seem discontinuous bases should be avoided.