Double-Sided Spoof Surface Plasmon Polaritons- Line Bandpass Filter With Excellent Dual-Band Filtering and Wide Upper Band Suppressions

This article presents a dual-band bandpass filter based on the double-sided spoof surface plasmon polaritons-line. The whole structure consists of a dual-band filtering part and two SSPPs lowpass filtering parts. Simulated results show that the proposed dual-band bandpass filter has an excellent dual-band filtering performance and wide upper band suppressions. Simulated bandwidths of two passbands are 41% (2.36-3.58 GHz) and 13.9% (6.7-7.7 GHz). It can realize the suppression of S21 below -40 dB from 9.6 to 39.7 GHz. A prototype has been fabricated and measured. Measured results are in a good agreement with simulated ones, which validates our design concepts and methods. The proposed dual-band bandpass filter will have significance in microwave device designing, especially in the plasmonic device in microwave frequencies.