Multifunction Tunable Metasurface for Entire-Space Electromagnetic Wave manipulation

Metasurfaces trigger great interests due to their potential ability to manipulate the propagation of electromagnetic (EM) waves. Plenty of fascinating EM phenomena have been generated using metasurface. However, two defects are hindering their development. The first one is that most metasurfaces only perform a specific functionality once designed, which means they do not possess tunable properties. The second defect is that most of them work in either reflection mode or transmission mode, leaving half of the EM space completely unexplored. Therefore, it is challenging to design metasurface with tunability and entire-space working modes simultaneously. Here, a tunable metasuface is presented to solve these problems. The proposed metasurface element is a multilayer structure which can manipulate EM waves in the entire space. Concurrently, p-i-n switches are loaded on each element which can dynamically control transmission and reflection phases. Thus, some intriguing EM modulation functions in the entire space are realized, such as beam forming, anomalous reflection, and diffusion. The simulated and experimental results prove the tunable metasurface. The proposed metasurface offers a feasible strategy to design tunable metadevices and for other related practical applications.