Liquid metal metasurface for flexible beam-steering.

In this paper, we propose a reconfigurable metasurface based on liquid metal for flexible beam-steering. The Gallium alloy with low melting temperature (about 30°C) is employed for easy structure reconfiguration. By designing specific dimension of cavity, we make the liquid metal in it easily form into desired sizes, to generate distinct phase responses. Two metasurface elements with four phase responses are designed, simulated and measured. Based on the above elements, various scattering fields can be realized within our design. We present four schemes to achieve single- and dual-beam fields with different beam-deflecting angles. The measured results show great agreement with the simulations, validating our design. In addition, every two columns of the metasurface are grouped into a single composite form, which promises a customizable combination for metasurface pattern. Compared to the previous reconfigurable works for metasurfaces, the method via liquid metal possess lower cost, easier fabrication, and will further enrich the manipulation method for metasurfaces.