High‐Efficiency Miniaturized Spoof Plasmonic Waveguide Filter from Direct Current to Millimeter‐Wave Frequency

Abstract

Spoof surface plasmon polaritons (SSPPs) are highly confined electromagnetic (EM) surface waves in microwave and millimeter‐wave frequencies, mimicking the surface plasmon polaritons (SPPs) in the optical frequency, which have many potential applications in plasmonic integrated circuits and systems. Herein, a miniaturized ultrathin SSPP structure is proposed by etching specially designed periodic elements on the coplanar waveguide (CPW), which has been successfully used to realize SSPP waveguide filters with high‐efficiency transmissions from the direct current to millimeter‐wave frequency region. By changing the dimensions of the SSPP structure, the cutoff frequency of the proposed plasmonic waveguide filter can be tuned from microwave to millimeter‐wave frequencies, maintaining the high transmission efficiency in the operating bandwidth. The physical mechanism is explained by the dispersion curves and field distributions. Experimental verification is conducted, which has good agreement with numerical simulations, indicating that the proposed plasmonic waveguide filter can help miniaturize the SSPP components and improve their integration with other devices in ultrawide frequency bands.

Keywords

• coplanar waveguide
• direct current
• low-pass filter
• spoof surface plasmon polaritons