Reconfigurable diffractive antenna with three degrees of freedom.

Diffractive antennas implement steerable beams based on reconfigurable diffractive devices such as Fresnel zone plates (FZPs). Compared with phased array systems, FZP antennas have concise architectures and simple beam‐steering mechanisms. In this Letter, the authors demonstrate an FZP‐based reconfigurable diffractive antenna with three degrees of freedom (3DoF), i.e. simultaneous reconfigurable steering angle, beamwidth and operating frequency. Such a highly reconfigurable antenna is implemented based on a single‐layer metasurface mounted with microwave varactors. The principle behind this 3DoF reconfiguration is the electrically induced transparency and opacity switched by different sets of binary voltages applied across the varactors. Experimental measurements validated the proposed approach. [ABSTRACT FROM AUTHOR]