Recent Progress in Reconfigurable and Intelligent Metasurfaces: A Comprehensive Review of Tuning Mechanisms, Hardware Designs, and Applications

Intelligent metasurfaces have gained significant importance in recent years due to their ability to dynamically manipulate electromagnetic (EM) waves. Their multifunctional characteristics, realized by incorporating active elements into the metasurface designs, have huge potential in numerous novel devices and exciting applications. In this article, recent progress in the field of intelligent metasurfaces are reviewed, focusing particularly on tuning mechanisms, hardware designs, and applications. Reconfigurable and programmable metasurfaces, classified as space gradient, time modulated, and space-time modulated metasurfaces, are discussed. Then, reconfigurable intelligent surfaces (RISs) that can alter their wireless environments, and are considered as a promising technology for sixth-generation communication networks, are explored. Next, the recent progress made in simultaneously transmitting and reflecting reconfigurable intelligent surfaces (STAR-RISs) that can achieve full-space EM wave control are summarized. Finally, the perspective on the challenges and future directions of intelligent metasurfaces are presented.

Automated summary

Intelligent metasurfaces, with the ability to dynamically manipulate electromagnetic waves, have gained significant importance in recent years. This article reviews the recent progress in the field of intelligent metasurfaces, focusing on tuning mechanisms, hardware designs, and applications. It discusses reconfigurable and programmable metasurfaces, as well as the potential of reconfigurable intelligent surfaces in altering wireless environments. Additionally, it summarizes the progress made in transmitting and reflecting reconfigurable intelligent surfaces that achieve full-space EM wave control. The perspective on the challenges and future directions of intelligent metasurfaces is also provided.