Fig. 1. Terahertz microfluidic sensor. (a) Sensor structure; (b) unit metal structure

Fig. 2. Equivalent circuit. (a) LC resonance; (b) dipole resonance

Fig. 3. Changes of Q-factor and absorption with different structural parameters. (a) Absorption and reflection spectra of the sensor; (b) L₁; (c) L₂; (d) L₃; (e) W; (f) θ

Fig. 4. Effects of microfluidic channel height and thickness of cap on the sensing properties. (a) Changes of Q-factor and absorption with different microfluidic channel height; (b) changes of sensitivity with different microfluidic channel height; (c) changes of sensitivity with different thickness of cap

Fig. 5. Electric field distribution and surface current distribution of metal microstructure at the resonance frequency point. (a) Electric field distribution; (b) surface current distribution

Fig. 6. Reflectance spectra of glucose solutions with different mass fractions

Table 1. Comparison of the proposed sensor with prior reported sensors

Table 2. Refractive index of glucose solution with different mass fractions at 20 ℃^[25]