A low-pass plasmonic filter based on spoof surface plasmon polaritons (SSPPs) is reported by etching the two grounds of coplanar waveguide with periodic grooves, the cutoff frequency of which can be tuned by the depth of the grooves at will.

A T-shaped groove is designed to increase the equivalent depth of the groove so as to realize the miniaturization of the proposed filter.

This simple low-pass plasmonic filter can find potential applications in plasmonic circuits and systems.