Using the ADI-FDTD Method to Simulate Graphene-Based FSS at Terahertz Frequency

The alternating-direction-implicit finite-difference time-domain (ADI-FDTD) method is modified to simulate a graphene-based frequency selective surface. By using the auxiliary differential equation and Pade fitting method, both the interband and intraband conductivity of the graphene are incorporated into the ADI-FDTD method. The ADI-FDTD method has excellent computational accuracy and its computational efficiency is considerably improved from that of the conventional FDTD method. By using the proposed ADI-FDTD method, a graphene-based frequency selective surface is simulated and analyzed at terahertz frequency. The numerical results show that the graphene can achieve a tunable frequency selective surface through controlling its chemical potential, and the interband conductivity of the graphene has important effect on the performance of the frequency selective surface.