Wideband analysis of a stop band filter and a resonator at THz frequencies

A THz stop band filer (TSBF) and a resonator consisting of metal plates with gratings are analyzed using the finite-difference time-domain method. The accuracy of a wideband response obtained from the pulse excitation technique is verified through comparison with the results from the continuous wave excitation technique. It is shown that the bandgap in the transmittance becomes wide as the air core width between the two metal plates is reduced. A resonator, in which a defect section is introduced to the TSBF, is also analyzed with special attention to the air core width. Numerical results show that tunable properties of resonance frequencies can readily be obtained.