Fig. 1. Structure of single-layer media. (a) FSS model; (b) equivalent circuit

Fig. 2. Schematic diagram of the unit structure of the model. (a) Overall structure; (b) top structure; (c) bottom structure; (d) section

Fig. 3. Equivalent circuit diagram of the unit structure

Fig. 4. Comparison of the simulation results by FDTD and ECM

Fig. 5. Varactor diode. (a) Equivalent circuit; (b) performance curve of the varactor diode

Fig. 6. S₁₁ curves of the outer ring loaded with varactor diodes

Fig. 7. S₁₁ curves of the inner ring loaded with varactor diodes

Fig. 8. Field intensity distributions at different resonant frequencies after loading varactor diodes. (a) 13.15 GHz (outer ring loaded with 0.6 pF varactor diode); (b) 19.50 GHz (inner ring loaded with 0.03 pF varactor diode)

Fig. 9. Effects of frequency response characteristics varied with the aperture size. (a) Radius of ring r₃; (b) radius of metal through-hole r_t

Fig. 10. Effects of frequency response characteristics varied with the medium properties. (a) Thickness of the medium; (b) dielectric constant of the material