Simulation of Diffraction in Periodic Media with a Coupled Finite Element and Plane Wave Approach

The aim of this paper is to discuss simulation methods of diffraction of electromagnetic waves on biperiodic structures. The region with complicated structures is discretised by Nédélec Finite Elements. In the unbounded homogeneous regions above and below, a plane wave expansion containing the exact far-field pattern is applied. A consistent coupling is achieved by the method of Nitsche. By numerical experiments we investigate the speed of convergence depending on the mesh refinement, the element order and the number of evanescent waves.