A Terahertz Bandpass Filter Using a Capacitive Transition Circuit and a Spoof Surface Plasmon Polariton Waveguide

TL;DR

This paper introduces a novel terahertz bandpass filter using a spoof surface plasmon polariton waveguide with cascaded high-pass and low-pass elements, achieving a 1 THz center frequency and 0.3 THz bandwidth.

Contribution

It presents the first SSPP-based terahertz bandpass filter with a unique design combining a capacitive transition circuit and SSPP waveguide.

Findings

Measurement results match theoretical predictions.

The filter operates at 1 THz with a 0.3 THz bandwidth.

The design is validated through simulations and experiments.

Abstract

This paper presents a novel terahertz (THz) bandpass filter (BPF) based on a spoof surface plasmon polariton (SSPP) waveguide with a center frequency of 1 THz and a 3 dB bandwidth of 0.3 THz. The proposed BPF comprises cascaded high-pass and low-pass elements. The high-pass element is a capacitive gap in the SSPP transition circuit, and the low-pass element is the SSPP waveguide itself. We find that the measurement results, including cut-off frequencies, align well with the theoretical predictions and simulations. To the authors' knowledge, the proposed SSPP BPF is the first of its kind.