Reconfigurable Reflective Metasurface for Dynamic Control of Focal Point Position

Spatial energy distribution is manipulated to control and focus an incident plane wave at any spatial position. For this purpose, an ultrathin reconfigurable reflective metasurface is designed through the use of unit cells incorporating voltage-controlled varactor diodes. The phase characteristic of each unit cell is individually controlled and allows to dynamically control the position of the focal point. Near-field measurements are performed on a fabricated prototype validating the concept.