Finite element method analysis for the frequency selective characteristics of dielectric periodic structure with arbitrary profiles

The dispersion characteristics of the dielectric Frequency Selective Surfaces with arbitrary profiles are analyzed by finite element method (FEM). The periodic structure is truncated to a single unit cell with the introduction of an exact periodic boundary condition, which is set according to Floquet´s theorem. The calculation region is truncated by the perfectly matched layer (PML). Finally, the incident wave is treated as the second inhomogeneous boundary conditions on the virtual incident plane. The combination of these boundary conditions simplified the calculation of the open space problems greatly.