The dispersion characteristics of PBG with complex medium by using non-Yee grid higher order FDTD method

Photonic band-gap (PBG) materials have recently attracted significant interest in the microwave region to suppress surface waves and to improve component performance. In this article, the NY-FDTD (nonYee grid higher order finite difference time-domain) formulation of a PBG structure in an anisotropic medium is derived, and then applied to compute the dispersion curves of 2D PBG structures. The numerical results for the isotropic medium are in good agreement with that from the traditional FDTD method. Then, the dispersion curves for anisotropic media are provided respectively. Which show that both the TM wave in the PBG structure with a magnetic-anisotropic medium and the TE wave in a PBG structure with an electric-anisotropic medium, possess an enhanced bandwidth of the first band-gap and also an increment of the number of bandgaps, compared to that of a PBG with isotropic medium.