Broadband electrically controlled reflective metasurface for reconfigurable circularly polarized wavefront manipulation.

A broadband, electrically controlled, reconfigurable, circularly polarized reflective metasurface is presented. The chirality of the metasurface structure is changed by switching active elements, which benefits from the tunable current distributions generated by the elaborately designed structure under x-polarized and y-polarized waves. Notably, the proposed metasurface unit cell maintains a good circular-polarization efficiency in a broadband range of 6.82-9.96 GHz (fractional bandwidth of 37%) with a phase difference of π between the two states. As a demonstration, a reconfigurable circularly polarized metasurface containing 8 × 8 elements was simulated and measured. The results verify that the proposed metasurface can flexibly control circularly polarized waves in a broadband, realizing beam splitting, mirror reflection, and other beam manipulations from 7.4 GHz to 9.9 GHz (fractional bandwidth of 28.9%) by simply adjusting the loaded active elements. The proposed reconfigurable metasurface may offer a promising approach to electromagnetic wave manipulation or communication systems.