Microwave

Quantum mechanics

Engineering

Materials science

Coplanar waveguide

Low-pass filter

Electric field

Telecommunications

Surface plasmon

Computer science

Prototype filter

Filter (signal processing)

Surface plasmon polariton

Polariton

Physics

Waveguide

Optics

Waveguide filter

Plasmon

Dispersion (optics)

Transmission line

Localized surface plasmon

Optoelectronics

Computer vision

Electrical engineering

Applied Physics Letters

In this letter, a coplanar waveguide (CPW) filter based on spoof surface plasmon polaritons (SSPPs) in the microwave frequency band is proposed, which can achieve multi-band transmission by using periodic holes etched on the middle line of a CPW. Compared to the conventional SSPP designs, the proposed SSPP-based waveguide filter removes the gradual structure for the mode conversion. Simultaneously, the transmission efficiency of high-order modes is obviously improved by employing periodic holes etched on both the side grounds of the CPW. The physical mechanism of the proposed SSPP-based waveguide filter is explained with the aid of the dispersion curves and electric field distributions. Experimental results validate the proposed concept, and the measured results are in good agreement with the simulated ones, which indicates that the proposed SSPP-based waveguide filter can find potential applications in plasmonic integrated circuits at microwave frequencies.

An ultra-thin coplanar waveguide filter based on the spoof surface plasmon polaritons