Enhanced Ultra-Sensitive Metamaterial Resonance Sensor based on Double Corrugated Metal stripe for Terahertz Sensing

In this paper, an ultra-sensitive metamaterial terahertz sensor is proposed. The resonance sensor is designed based on a novel double corrugation form to enhance the ability of the sensor in the terms of sensitivity, Q-factor and the maximum sensible thickness of an analyte. The introduced structure can support the spoof surface plasmon and can resonate strongly at the tuned frequencies. Moreover, the structure of the terahertz sensor is investigated thoroughly from different points of view including frequency shifts due to variations in the thickness or refractive index of the analyte. In addition, the sensitivity of the sensor is approximated with a biharmonic fitting function for different combinations of refractive index and analyte thickness as "sensitivity surface". The sensor shows the maximum sensitivity of 1.75 THz/RIU for refractive index between 1-1.2 with a maximum thickness of 80 μm. Moreover, the simulation results approved that the double corrugation on the metal stripe improves the electromagnetic field interaction in the metal part greatly in comparison with the previously reported works. According to this work, the proposed structure can be applied for terahertz sensing with more abilities to sense even thicker biologic tissues.