A Compact Rejection Filter Based on 2.5-D Spoof Surface Plasmon Polaritons and Folded Spilt-Ring Resonators

TL;DR

This paper introduces a compact microwave rejection filter utilizing 2.5-D spoof surface plasmon polaritons and folded split-ring resonators, achieving adjustable rejection bands and significantly reduced size.

Contribution

It presents a novel compact filter design combining 2.5-D SSPP and folded SRRs, with independently tunable rejection and cut-off frequencies, and a 54% size reduction.

Findings

Achieved ultra-wide passband with a rejection band.

Independent adjustment of rejection and cut-off frequencies.

Reduced lateral size by 54% compared to conventional designs.

Abstract

In this paper, a compact rejection filter is proposed based on 2.5-D spoof surface plasmon polariton (SSPP) structure and folded spilt-ring resonators (SRRs). By embedding the folded SRRs into periodic grooves of the 2.5-D SSPP transmission line, a rejection band is created in the ultra-wide passband, resulting in pass-rejection-pass frequency characteristics. The rejection band and the cut-off frequency of the filter can be adjusted independently by changing the geometrical parameters of the 2.5-D SSPP rejection unit. Because of the compact folding structure, the lateral size is reduced by 54% compared with the conventional 2-D SSPP rejection filter.