Wireless Communications beyond Antennas: The Role of Reconfigurable Intelligent Surfaces †

Reconfigurable intelligent surfaces (RISs) are a new and emerging technology that has the potential to revolutionize the way that wireless communication systems are designed and implemented. These surfaces are made up of a large number of small, individually controllable elements, each of which can be used to manipulate the phase and amplitude of the electromagnetic waves that pass through it. This allows them to perform a wide range of functions, including wireless power transfer, beamforming, and cloaking. In this work, we provide an overview of the principles and applications of reconfigurable intelligent surfaces, and we discuss the advantages and challenges of these surfaces in wireless communications. We also provide an overview of the current state of research in this area. Moreover, we outline the future directions for the development of these surfaces.