A Frequency Tunable Metagrating Absorber within an Expanded Frequency Band

Here, we demonstrate a novel frequency tunable metagrating absorber in the non-narrow frequency band. A supercell is designed to be controllable by the introduction of a commercial varactor diode, enabling tuning load impedance density flexibly. The absorption frequencies of the designed metagrating can be controlled continuously, by adjusting the bias voltage on the selected varactor diode. The numerical simulation results indicate the proposed tunable absorber exhibits near-perfect absorption properties ranging from 9 GHz to 11 GHz.