Design of a Low Insertion Loss and High Selectivity Bandpass Filter at the Terahertz Band

In response to the issue of both the transmission performance and the selection performance of the terahertz waveguide bandpass filter, this paper proposes a terahertz waveguide bandpass filter with out-of-band dual transmission zeros. The center frequency of the filter is 342GHz, the in-band insertion loss is less than 0.4dB, and the return loss is less than 20Db. The 3-dB passband is 324-360GHz, the 30-dB fraction bandwidth is 322-363GHz, so the 30-dB rectangular coefficient is 0.88. The bandpass filter proposed in this article presents excellent performances with high frequency selectivity and low insertion loss. For terahertz band application, this high-performance bandpass filter would have a great potential.