Fig. 1. Metamaterial absorbing structure. (a) Unit cell; (b) top view of middle layer; (c) overall structure

Fig. 2. Complex permittivity at different temperature

Fig. 3. Absorptivity curve of water-based metamaterial absorber

Fig. 4. Absorptivity curves of resin shell, full water layer, and annular water column

Fig. 5. Equivalent complex impedance of metamaterial absorber

Fig. 6. Vector field distributions of metamaterial absorber. (a) Electric field distributions; (b) magnetic field distributions; (c) power loss density

Fig. 7. Absorptivity of metamaterial absorber with different incident angles. (a) TE polarization; (b) TM polarization

Fig. 8. Absorptivity of metamaterial absorber at different polarization angles

Fig. 9. Absorptivity of absorber at different temperature