A Four-Band Terahertz Metamaterial Sensor Based on Symmetric E-Shaped Structure

To realize the multi-frequency selectivity of the analyte, a novel four-band terahertz metamaterial sensor is proposed in this work. In particular, the sensor performance is analyzed theoretically and numerically within a terahertz frequency range (0.8–1.5 THz) via the finite element method. According to the results, higher-order Fano resonance is the main cause of the four narrow and sharp transmission valleys in the operating band region of the sensor, yielding high resolution with Q values up to 177. Moreover, this sensor is polarization-insensitive over a wide polarization angle range of 0° to 50°. In addition, the sensor achieves refractive index sensitivity of 200 GHz/RIU and offers FOM values of up to 26.7. The sensor proposed in this study exhibits a simple structure, frequency selection characteristics, low cost, and enhances the interaction between terahertz waves and substances, which is of great theoretical and practical significance for the development of terahertz functional devices such as sensors and filters.