Broadband liquid sensing with a spoof plasmon transmission line

Abstract

One of the most remarkable features of surface plasmon polaritons (SPPs) is their usefulness for sensing. In this paper, we introduce a spoof SPP sensor consisting of a transmission line with a rectangular groove array. We investigated its dispersion relation and verified the broadband transmission characteristics of its SPP mode. A sensing model with spoof SPPs has been developed and a prototype fabricated. Three analytes with different permittivity were introduced into the model and prototype — edible oil, glycerol, and water — and the results compared to those obtained with air. The results of simulation and measurement show that the sensor is extremely sensitive to the permittivity of a liquid. The results indicate that spoof SPP sensors have important potential applications in industrial processing, food safety, and environmental monitoring.