A Novel Transition Device and Multiple Band-Pass Filter Using Ring Resonator Based on Spoof Surface Plasmon Polaritons at Microwave Frequency

In this paper, we report the development of a broadband transition from QTEM mode to SSPP mode which have been subsequently used to develop a multiband band pass filter. A trapezoidal shape periodically corrugated metallic grooves, which shows enhanced confinement of surface wave; have been used in the implementation of transition and filter. In the design of back to back transition, matching between QTEM and SSPP mode has been achieved using gradient grooves. The developed transition has been used to experimentally characterize a ring resonator where ring has been corrugated with periodical array of trapezoidal shaped grooves. This ring resonator shows multiple pass bands at different frequencies within the specified frequency range. Simulated and measured characteristics of transition and ring resonator have been found in good agreement.