Fig. 1. Schematics of absorber based on water-based metamaterial. (a) Unit structure; (b) diagram of water cavity; (c) side view of unit; (d) top view of unit

Fig. 2. Fabrication and measurement of sample. (a) Sample；(b) experiment platform

Fig. 3. Spectra of reflection and absorption. (a) Simulated and measured reflectance spectra; (b) simulated and measured absorption spectra

Fig. 4. Equivalent impedance of absorber

Fig. 5. Field distributions of water-based metamaterial absorber at peak absorption frequency of 28.28 GHz. (a) Electric field distribution; (b) magnetic field distribution; (c) power loss density distribution

Fig. 6. Absorption spectra under different material parameters

Fig. 7. Influence of structure and material parameters on absorption spectra of absorber. (a) Width of internal medium layer；(b) cross-sectional area of water cavity; (c) water temperature

Fig. 8. Effect of polarization angle on absorption spectrum of absorber. (a) Simulated results; (b) test results

Fig. 9. Effect of incident angle on absorption spectrum of absorber under TE polarization. (a) Simulated results; (b) test results

Fig. 10. Effect of incident angle on absorption spectrum of absorber under TM polarization. (a) Simulated results; (b) test results