Design of four-channel photonic crystal filter based on gyromagnetic materials

In this paper, the coupled mode theory is studied to derive the conditions to achieve high coupling between a photonic crystal (PC) resonant and PC waveguide. Then the ferrite material as yttrium iron garnet (YIG) is introduced to the resonant to get some amazing characteristics as a four-channel PC microwave filters. Meanwhile, Finite Element Method is performed for simulation for the filter structures in both the situations with or without the external magnetic field. The simulation results imply that the designed filter could choose the channel for the propagating electromagnetic wave by tuning the external magnetic field.