Design and investigation of a transparent and actively tunable broadband electromagnetic wave-absorbing metamaterial

Abstract With the development of electronic information technology, the demand for electromagnetic wave-absorbing materials with special characteristics such as transparency and tunability has surged. Here, a transparent and actively tunable broadband electromagnetic wave-absorbing metamaterial combined with diodes and indium tin oxide is designed and experimentally realized, achieving a transmittance of 71.9% and an effective absorption (reflection loss ( RL ) < −10 dB) bandwidth of 10.1 GHz (7.9–18 GHz). The RL of the sample changes from −35.95 dB to −11.53 dB at 9.69 GHz and from −11.11 dB to −42.29 dB at 15.83 GHz when the applied voltage is varied from 10 V to 20 V. In addition, the modulatory mechanisms of the absorption performance are investigated. The tunable RL is attributed to variations in the reflection, transmission and absorption of the metasurface and to the presence of multiple reflection mechanisms, which are essentially related to the electromagnetic coupling effect on the metasurface. This work lays the foundation for the preparation of wave-absorbing materials applicable to special scenarios and provides guidance for the modulation of the absorptive properties of metamaterials.