Fig. 1. Effect of graphene content on complex permittivity of single-layer sample. (a) Effect on real part; (b) effect on imaginary part

Fig. 2. tanδ and conductivity of single-layer samples with different graphene contents. (a) tanδ; (b) conductivity

Fig. 3. Reflectivity and frequency for homogeneous single-layer samples with different graphene contents and different absorption layer thicknesses. (a) 7%; (b) 8%; (c) 9%

Fig. 4. Reflectivity and optimal matching thickness of single-layer sample with graphene mass fraction of 7% and different absorption layer thicknesses. (a) Reflectivity; (b) optimal matching thickness

Fig. 5. Testing sample of three-layer wave absorber and bow-shaped device for measuring reflectivity. (a) Test sample; (b) device for measuring reflectivity

Fig. 6. Reflectivity of 5 samples of three-layer wave absorber and their frequency bandwidths with reflectivity of less than -10 dB and -20 dB, respectively. (a) Reflectivity; (b) frequency bandwidth