In order to reduce the Full Width at Half Maximum(FWHM) of slot-type cavity filters
we numerically simulate the structures of the Metal-Insulator-Metal(MIM) waveguide-based single slot-and cascaded slot-type cavity filters by using the Finite-Difference Time-Domain(FDTD) method and analyze their transmission spectra by using the coupled mode theory.The simulation results show that the FWHM of the transmission spectrum of the cascaded slot-type cavity filters can be effectively suppressed to be only about 30%
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0% of that of the single slot-type cavity filters.