An ultra-wideband low-pass plasmonic filter based on spoof surface plasmon polaritons

In this work, a smooth bridge between a traditional microstrip line and a two parallel metallic strips drilled with symmetrical grooves is designed to achieve ultra-wideband low-pass filtering characteristics. Numerical simulations on the S-parameters demonstrate the good performance in the whole pass band. This kind of plasmonic filter poses potential applications in developing advanced plasmonic integrated circuits in the microwave and terahertz frequencies.