Low Profile Optically Transparent Microwave Absorber with broadband absorption

An optically transparent double-layer absorber with thickness of 4.25 mm is reported in this paper. This absorber is composed of a square ring pattern on the upper layer and a block pattern on the lower layer. The polymethyl methacrylate material is selected as a dielectric layer in the middle served as a link to satisfied high optical transparency requirements. Through the multi-layer cascade theory, the pattern of the indium tin oxide film is designed to match the air impedance. Finally, the simulation results and the experiment collectively demonstrate this absorber can achieve an absorption effect of −10 dB within the frequency band of 6–18 GHz.