Dispersion relation of spoof surface plasmon resonant mode on concentric annular metal corrugation

Abstract

In this study, we demonstrate near-field measurement of a spoof surface plasmon (SSP) on a corrugated metal disk with concentric annular corrugation. The SSP is excited at the center of the disk and is probed by a needle antenna on the corrugated surface. In the measurement, SSP resonant modes are observed around the upper cut-off frequency. The dispersion relation and group velocity are extracted from the measured parameters and correspond well to the calculated dispersion relation. Our results help in designing SSP resonators to improve the device performance of an intense terahertz wave source.