Wavefront Control of Millimeter Waves With a VO2-Based Reconfigurable Meta-Reflectarray

In this paper, a novel architecture of a reconfigurable metasurface is proposed and numerically assessed for wavefront control in wireless systems working in the millimeter-wave range. We show that a metasurface made of engineered silicon bricks covered with a thin film of vanadium dioxide provides anomalous reflection with an efficiency of 93% at 60 GHz and a relative bandwidth of 15%. After applying a thermal stimulus that triggers the transition of vanadium dioxide from the insulator phase to the metallic phase, the metasurface abruptly changes its response and provides specular reflection. The device shows high efficiency and broadband operation in both VO2 states, allowing dynamic control of millimeter waves. Therefore, it finds applications in imaging, sensing, and intelligent wireless communications in 5G and 6G systems, especially for beam-shaping and beam-steering. Moreover, the proposed reconfigurable metasurface has a simple configuration that lends itself to standard fabrication tools, and it has a subwavelength size for integrated and compact communication systems.