Ionogel-based optically transparent multifunctional metasurface for tunable microwave absorption and vibrational energy harvesting

In this work, a multifunctional metasurface with microwave absorption and electrostatic vibrational energy-harvesting functions is proposed. The structure consists of ITO conductive glasses and ionogel. Ionogel fully exploits the properties of ionic liquids and endows the devices with good mechanical properties. The experimental results show that when the height of the metasurface is 3.4 mm, the reflection coefficient is lower than -10 dB from 6.11 GHz to 13.50 GHz. As the height decreases, the absorption bandwidth gradually shifts towards higher frequencies. Moreover, the vibrational energy harvesting is based on the principle of electric double layer modulation, and a 7 × 9 metasurface array can achieve a voltage output of 524 mV on a 50 MΩ load. The experimental results match well with the theoretical simulation, confirming the feasibility of this scheme and providing a new solution for designing multifunctional metasurfaces.