Electromagnetic metasurfaces provide unprecedented control over electromagnetic waves. With surfaces tailored to achieve specific responses to incident electromagnetic waves, they offer fascinating functionalities in different applications ranging from microwave antennas to nano-optics. However, most existing metasurfaces perform a static function dictated by their fixed geometrical parameters. Tunable metasurfaces, on the other hand, offer a unique multifunctional platform for dynamically manipulating electromagnetic wave fronts. We introduce a transmissive metasurface that is capable of electronically tuning the polarization of an arbitrarily polarized incident wave.

The proposed metasurface is a periodic assembly of small pixels (unit cells), whose transmission phase is electronically tunable using varactor diodes integrated into their design. We employ a simple voltage-biasing scheme that does not interfere with the microwave performance of the metasurface. Using experiments and numerical simulations, we show that this design can rotate the polarization of an incoming wave. At the operating frequency of 10 GHz, the polarization rotator achieves an overall rotation angle of 146°.

Our reported metasurface-based approach to dynamic phase and polarization control will open new opportunities in the real-time manipulation of electromagnetic waves.