Rigorous coupled wave analysis upgraded with combined boundary conditions method for 2D metamaterials in microwave

We combine rigorous coupled wave analysis (RCWA) and combined boundary conditions method (CBCM) to analyze optical properties of two-dimensional periodic metamaterial grating with arbitrary shapes in microwave domain, and the adaptive spatial resolution (ASR) function is introduced to increase convergence especially for the crossed metamaterial gratings. The numerical results show that RCWA with CBCM can get the correct convergence result and distinguish the contribution of the grating lobes to the total transmission and reflection. The ASR technique improves dramatically the convergence speed of crossed grating. This method provides a more effective computational tool for the design of metamaterial grating in microwave domain.