Fig. 1. Three-dimensional schematic of proposed metamaterial sensor and schematic of metamaterial unit cell with geometric dimensions. (a) Structure of metamaterial sensor; (b) structure of metamaterial unit cell

Fig. 2. Optical spectra of the unit cell and two substructures of metamaterials. (a) Reflection spectrum and absorption spectrum of metamaterial unit structure and transmission spectrum of transmission structure; (b) reflection spectrum of two substructures

Fig. 3. Electric field intensity distributions of three structures at 0.8232 THz. (a) Cut wire; (b) DSRRs; (c) proposed structure

Fig. 4. Current distributions in surface resonance layer and bottom metal reflector of three structures at 0.8232 THz. (a)(d) Cut wire; (b)(e) DSRRs; (c)(f) proposed structure

Fig. 5. Reflected spectrum at different coupling distances

Fig. 6. Correspondence curves of coupling distance s and quality factor Q

Fig. 7. Schematic of sensor and simulated reflection spectra. (a) Three-dimensional diagram of sensor with analyte;(b) reflection spectra of sensors with (d=10 μm,n=1.6) and without analyte

Fig. 8. Equivalent circuit model corresponding to proposed sensor

Fig. 9. Exponential function fitting curve between analyte thickness and frequency shift

Fig. 10. Reflection spectra corresponding to different refractive indices

Fig. 11. Frequency shifts corresponding to different refractive indices and linear fitting function curves