A K-band Spoof Surface Plasmon Polaritons Bandstop Filter with Capacitively Loaded Split-ring Resonator

摘要

A K-band bandstop filter based on the spoof surface plasmon polaritons (SPP) and the capacitively loaded split-ring resonator (RSS) is proposed in this paper. The capacitively loaded RSS consists of two parts: the traditional rectangle RSS and a T-type stub placed at the center of the arm microstrip line of the rectangle RSS. Thanks to the capacitively loaded RSS, the operating frequency of the resonator is reduced, which is helpful for miniaturizing the circuit size. The dispersion feature of the capacitively loaded RSS is studied by simulation and the geometrical parameters effects on the filter's final performance are discussed. A K-band bandstop filter with spoof SPP and capacitively loaded RSS is designed, fabricated and measured to verify the proposed design methodology. The measured results show that the bandstop filter works at 21.05 GHz-22.95 GHz with more than 40 dB insertion loss.