Graphene-Integrated Reconfigurable Metasurface for Independent Manipulation of Reflection Magnitude and Phase

Reconfigurable metasurfaces are highly desirable for applications including dynamical camouflaging, intelligent electromagnetic (EM) skin and systems due to their tunable EM features or functions. So far most of the existing reconfigurable metasurfaces are developed by modulating their amplitude or phase. It is still very challenging to simultaneously achieve dynamical control of amplitude and phase in one design. This study reports a reconfigurable metasurface that can realize independent control of reflection magnitude and phase with the external bias voltages. In this metasurface, the graphene capacitor structure is used as an amplitude-tuning layer for controlling the reflection magnitude by changing the effective sheet resistance of graphene, while the reflection phase is tuned by switching PIN diodes loaded in a periodic metallic structure. Such metasurface can control the scattering wave directions through phase coding, and the variation of graphene resistance can further modulate the intensity of the scattering beams. In addition, the metasurface can also function as a radar absorber where the absorbing magnitude and frequency can be dynamically tuned. Good agreements between simulations and experiments demonstrate its powerful ability to manipulate the EM waves by simultaneously tuning the reflection magnitude and phase, indicating a wide range of potential applications in EM fields.