In this paper, we present a terahertz (THz) band-stop filter realized by fabricating a metallic T-shaped resonator pattern on the high-resistivity silicon wafer. The filter exhibits two typical band-stop response characteristics depending on the incident direction of electric field with respect to the T-shaped resonator. When the long and the short arms of the T-shaped resonator were electrically polarized by changing the incident THz wave transmission directions, the corresponding central frequencies of the band-stop filter were found to be 0.436 THz at 42dB and 0.610 THz at 28 dB, respectively. Using three-dimensional (3D) finite-integral time-domain simulations, the band-stop filter was designed, which can operate in the wavelength between 0.2 and 0.8 THz. Experimental verification was also performed using a free space THz time-domain spectroscopy system. The band-stop response characteristics are in good agreement with the simulation results. The interesting THz band-stop filtering properties suggest a promising application in the modern THz communication systems, THz time-domain spectroscopic imaging and THz continuous wave imaging.
