Dynamically controlling electromagnetic reflection using reconfigurable water-based metasurfaces

We proposed and demonstrated a reconfigurable water-based metasurface to achieve continuously dynamic control of electromagnetic (EM) reflection within a wide frequency band. The proposed metasurface is an array of an anisotropic unit cell consisting of two metallic layers separated by a dielectric layer. The flowing channel of the distilled water is designed in the dielectric spacer, so the metasurface is reconfigured by simply changing the injection quantity of water. Calculated, simulated and real-time measured results show that the reflection almost monotonically reduces as the water is injected into the metasurface, and the tunable level of reflection is larger than 10 dB from 8 to 18 GHz during the reconfiguring process. Besides the absorption resulting from the injected water, the EM reflection variation is partly contributed to the scattering mechanism. The results here provide an effective solution to flexibly control EM reflection from an object, and may find potential applications in the design of the adaptive EM surfaces and devices.