Fig. 1. Schematic diagram of absorber structure. (a) Structural diagram of unit cell; (b) top view of unit cell

Fig. 2. Simulation curves of absorption rate, S parameters, and metasurface equivalent impedance of absorber. (a) Absorptivity and S parameters; (b) equivalent impedance

Fig. 3. Absorption rate simulation curves of absorber at different polarization angles (φ)

Fig. 4. Absorption rate simulation curves of absorber at different incident angles (θ). (a) TE polarization; (b) TM polarization

Fig. 5. Z_eff curves at different incident angles (θ). (a) TE polarization; (b) TM polarization

Fig. 6. Power loss in each layer of absorber

Fig. 7. Distribution diagrams of electric field and current of 2×2 absorber unit cells. (a) Surface electric field distribution, (c) surface current distribution of top ITO, and (e) surface current distribution of back ITO at 8.6 GHz; (b) surface electric field distribution, (d) surface current distribution of top ITO, and (f) surface current distribution of back ITO at 11.2 GHz

Fig. 8. Robustness analysis of absorber structural parameters. (a) t₂; (b) d; (c) R; (d) L₁; (e) L₂; (f) L₃

Fig. 9. Physical photos and optical transmittance curve of absorber. (a) Physical photo; (b) optical transmittance curve and thickness

Fig. 10. Morphological images of absorber surface. (a) Schematic diagram of absorber surface structure; (b) optical microscope photograph of absorber surface (edge region); (c) optical microscope photograph of absorber surface (center region)

Fig. 11. Comparison of measured and simulated absorptivity of absorber at vertical incidence

Fig. 12. Measured absorptivity curves of absorber at oblique incidence. (a) TE polarization; (b) TM polarization

Fig. 13. Infrared emissivity test curve of absorber metasurface functional layer

Fig. 14. Thermal infrared image