Highly reliable and ultra-wideband metamaterial absorber based on graphene-assembled films for extremes

Metamaterial absorbers have demonstrated significant potential in mitigating electromagnetic pollution, yet there is a dearth of research on absorbers that function effectively in extreme environments. In this work, a highly reliable and ultra-wideband metamaterial absorber based on graphene-assembled films (GAFs) is proposed. The presented absorber consists of four-layer structures, including a high-resistance GAF pattern layer, a polyimide medium layer, an air layer, and a low-resistance GAF layer. The periodic ring structure made of highresistance GAF by screen printing with a sheet resistance of 57 Omega/sq exhibits excellent characteristics of wideband absorption and broad incidence angle absorption. The GAF absorber demonstrates a measured absorption efficiency exceeding 90 %, covering 4.24-17.90 GHz, and has a relative bandwidth of 123.4 %, which exhibits good stability when electromagnetic waves are incident at 0-30 degrees. More importantly, the GAF absorber maintains excellent performance in various extreme conditions, including acid, alkali, salt spray, high-humidity, hightemperature, and low-temperature environments. Therefore, the GAF absorber demonstrates consistent reliability and stability under extreme conditions, which is significant for electromagnetic protection under extremes.