A NodeMCU-Based Programmable Reconfigurable Intelligent Surface for mm-Wave 5G Applications

The reconfigurable intelligent surface (RIS) is a promising technology in metamaterial advancements for millimeter wave (mm-Wave) applications that could revolutionize future 6G wireless communications. RIS surfaces offers energy and spectrum efficiency by providing extended signal coverage and improved data rates. In this article, a compact RIS unit cell is realized, and its operation is demonstrated using simulation results. The footprint of the unit cell is 10x10x1.6mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup>. The unit cell is designed using an FR4 substrate with a G-shaped patch layer and full ground plane. The VO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> (Vanadium dioxide) is used as a reconfigurable element for getting beam-forming capability. The switching states give peak resonance at 24.3 GHz (OFF), 24.4 GHz, and 30.05 GHz (ON). The radiation efficiency at the operating frequencies is −13.75 dB, −7.63 dB, and −5.73 dB. The NodeMCU-based bias setup is demonstrated for getting the controllable states of VO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>. Hence, the programmable feature along with the beam forming capability is realized to meet the emerging trends and demands in mm-Wave 5G communications.