Substrate Integrated Plasmonic Waveguide Based Wideband Terahertz Band-Pass Filter

A planar terahertz bandpass filter has been designed by analyzing the dispersion characteristics of substrate integrated waveguide (SIW) and spoof surface plasmon polariton (SSPP). This design took advantage of the low-pass properties of SSPP and the high-pass attributes of SIW to achieve a wideband filter. In this design, the passband effectively covers a 3 dB frequency range of 0.3 THz to 0.7 THz while maintaining return losses consistently below -12.5 dB. The simulated insertion loss(IL) is 1.17 dB around the center frequency. The simulation results demonstrate that the designed filters exhibit sharp rejection out-of-band, possess a compact layout, and deliver a strong filtering response. These outcomes serve as compelling evidence of the filters' practical feasibility.