Dynamic Scattering Steering with Graphene-Based Coding Metamirror

The recent development of metasurfaces offers a unique technique for the arbitrary control of electromagnetic waves by spatially manipulating their amplitudes and phases. However, real time control in metasurfaces typically depends solely on dynamical phase modulation, but lacks of the amplitude modulation. In this paper, the dynamical amplitude modulation is tried to combine with phase coding metasurface, for the dynamical manipulation of electromagnetic scattering at microwave frequencies. Such an active metasurface is achieved by placing a patterned graphene layer on binary metallic resonators. When applying bias voltages on the graphene layer, continuous reflection amplitude modulation can be achieved for the selected resonators while the others are not affected. By this merit, two degrees of freedom, preset phase coding and dynamical amplitude modulation, are obtained to control the electromagnetic wave. As an example, a metasurface that can dynamically and continuously control the scattering pattern from mirror reflection to diffusion scattering is shown. The above concepts and physical phenomena are confirmed by numerical simulations and experiments.