Fig. 1. Structural diagrams and geometric parameters of metamaterial filter unit. (a) Three-dimensional diagram; (b) top view; (c) side view

Fig. 2. Transmission rate and transmission coefficient magnitude curves of metamaterial filter

Fig. 3. Surface current distributions of metamaterial filter at resonance frequencies. Surface current distributions of top layer at (a) f₁=4.74 THz and (b) f₂=5.64 THz; surface current distributions of bottom layer at (c) f₁=4.74 THz and (d) f₂=5.64 THz

Fig. 4. Equivalent models of top layer of metamaterial filter. (a) Equivalent circuit; (b) simplified circuit

Fig. 5. Equivalent circuit model of metamaterial filter

Fig. 6. Magnitude and phase comparison of transmission coefficients. (a) Magnitude; (b) phase

Fig. 7. Simulated transmission spectra of metamaterial filter under different conditions. (a) Different temperatures; (b) different conductivities of vanadium dioxide

Fig. 8. Simulated magnetic field distributions of metamaterial filter when vanadium dioxide undergoes phase transition. (a) Top layer structure of metamaterial filter; (b) equivalent top layer structure and (c) magnetic field distribution at high resonance frequency when conductivity of vanadium dioxide is σ=10 S/m; (d) equivalent top layer structure and (e) magnetic field distribution at high resonance frequency when conductivity of vanadium dioxide is σ=200000 S/m

Fig. 9. Simulated transmission coefficient S₂₁ by EC and EM when σ=1000 S/m. (a) Magnitude; (b) phase

Fig. 10. Simulated transmission coefficient S₂₁ by EC and EM when σ=50000 S/m. (a) Magnitude; (b) phase

Fig. 11. Simulated transmission coefficient S₂₁ by EC and EM when σ=200000 S/m. (a) Magnitude; (b) phase

Fig. 12. Transmission spectra of metamaterial filter versus incident angle for different polarization modes. (a) TE; (b) TM