Terahertz bandpass properties based on multiple slits in a parallel-plate waveguide

This paper reports on the development of terahertz (THz) bandpass properties with a transverse electromagnetic (TEM) mode by using two multiple-slit plates that serve as parallel-plate waveguides (PPWGs). The lower multiple-slit plate, which has a 500-A mu m period, shifts to the THz propagation direction by 270 A mu m to remove Bragg and Bragg-related resonances. The resonance frequency of the bandpass depends on the air gap between the two plates. The bandwidths of the simulated resonances are 41 GHz and 47 GHz for 90-A mu m and 160-A mu m air gaps, respectively. Although the amplitudes of the measured bandpass resonances are less than those of the simulations, the resonance frequencies of the measurements and the simulations are in good agreement.