A Practical Modeling Approach on the Reflectivity Characteristics of Reconfigurable Intelligent Surfaces

Reconfigurable intelligent surface (RIS) has been one of the most exciting and attractive topics in the beyond 5G era. Its advantages especially in providing coverage extension, signal-to-noise ratio and throughput enhancement, physical-layer security under non-line-of-sight (NLoS) conditions, and the support in other enabler 6G technologies and functionalities such as massive multiple-input multiple-output (mMIMO) schemes and joint communications and sensing (JCAS) have been popular research topics for the wireless communications community. Hence, the industrial initiative has also moved few steps forward to provide preliminary RIS prototypes those would be expected to support field trials and proof-of-concept (PoC) studies through the standardization stages. However, due to both the high costs associated with the production process (i.e., based on the PIN-diode-based designs) and the limited functionality of current prototypes (e.g., reflective-only opaque designs without any active elements), a clear conclusion has not been reached regarding the utilization of RIS hardwares within mobile communications networks. As we approach the standards and preliminary systems and network designs of 6G technology, measurement-based approaches towards clarifying the use cases of RIS hardware are seen not to respond to all possible requirements of poC studies. At this point, in order to examine the advantages of RIS technology, realistic computer simulations are believed to be capable of dispelling the uncertainty cloud in front of this technology. For this purpose, in this paper, a realistic surface scattering approach that addresses major drawbacks of the current reference evaluation methods has been proposed, and preliminary results have been exhibited.