Design and Optimization of Terahertz Bandpass Filter Based on SiC Substrate

In this paper, a substrate integrated waveguide (SIW) bandpass filter with the cascade quadruplet (CQ) topology working in the terahertz range was designed based on a SiC substrate. To achieve an improved out-of-band suppression performance, a special negative coupling scheme was used to introduce a transmission zero (TZ) in each side of the passband. During the design process, the aggressive space mapping method (ASM) was applied to improve optimization efficiency. The simulation result shows that the filter has a center frequency of 172GHz and bandwidth of 3.26GHz. The return loss in the passband is -20dB and the Out-of-band suppression is greater than 40dB.