Simulation of terahertz-band metamaterial sensor for thin film analyte detection

A terahertz metamaterial sensor for thin film sensing is proposed and investigated by a numerical study. The designed metamaterial sensor consists of an array of back to back c-shaped double-gap resonators, which can be obtained by simple manufacturing processes. By checking the shift of the resonate frequency of the sensor, the thickness of the analytes deposited on the sensor surface can be identified. We analyzed the sensitivities and corresponding quality factors of the sensor excited by two orthogonal polarized terahertz waves individually for both loss-free and lossy coating analyte layers. The electric field distributions of the metamaterial sensor with different analyte thicknesses are analyzed in detail to illustrate the principle of thin film detection and the principle of improving sensitivity. The transmission line model is built to verify the results of the numerical simulation. This study provides a useful reference for the design of biosensors based on metamaterial sensors in the future.