Proposal and theoretical design of THz bandpass filters using metallic photonic crystal resonators

By application of the global bandgap of metallic photonic crystal (M-PhC) structure, novel monopole-mode point-defect resonators are proposed to design bandpass filters (BPFs) in THz regime. Firstly, the bandgap structure of the proposed square-lattice M-PhC is calculated as well as the mode chart of the monopole-mode point-defect resonator. Secondly, two bandpass filters consisting of multistage of M-PhC point-defect resonators are synthesized using coupling matrix method. The first one is a 4
^th
-order Chebyshev-type filter based on an inline structure. The second one is realized by the re-arrangement of four resonators in the 1
^st
filter to obtain a compact size. The FDTD simulation results are in good agreement with the synthesized results, which confirms the validity of the proposed filter structures and design approach.