Space-Energy Digital-Coding Metasurface Based on an Active Amplifier

The metasurface has aroused broad enthusiasm due to its splendid properties for electromagnetic (EM) wave manipulations. However, most previous metasurfaces, including passive and active metasurfaces, are almost energy losing when controlling EM waves. Some amplifying metasurfaces have been proposed, but the amplification function is uncontrollable. Here, we propose a spatial-energy digital-coding metasurface with active amplifiers to realize arbitrary editing of the energy of spatial propagating waves. Based on the proposed metasurface, the spatial energy of a linearly polarized propagating wave can not only be amplified, but can also be edited into arbitrary magnitudes (including amplification and reduction) by controlling the voltage. A metasurface element integrated with an amplifier chip is designed for energy modulations in the microwave frequency range. The numerical simulations and experimental results show good consistency, validating the feasibility of our design.