Dynamical absorption manipulation in a graphene-based optically transparent and flexible metasurface

Microwave absorbing metasurfaces with optical transparency are essentially useful in electromagnetic compatibility, stealth, or camouflage while keeping continuous optical observation or communication. Although significant efforts have been devoted on expanding the bandwidths of optically transparent absorbing metasurfaces, dynamic control of microwave absorption in such metasurfaces remains a challenge. In this paper, we experimentally propose a metasurface made of patterned graphene sandwich structures, showing unprecedented wave control, excellent optical transparency and outstanding flexibility. Both the simulated and measured results demonstrate that the tunable absorption with dual, single and broad band are realized by applying bias voltage to graphene layers. In particular, the asdesigned metasurface shows a strong microwave absorption of 90% covering a wide frequency band of 7-18 GHz due to the electric and magnetic resonances caused by the patterned graphene layer, as well as the multiple reflection mechanism. We speculate that such a metasurface with optical transparency and tunable microwave absorption has potential applications in stealth technology and photovoltaic solar cells. (C) 2021 Elsevier Ltd. All rights reserved.