An Equivalence Principle-Based Hybrid Method for Propagation Modeling in Radio Environments With Reconfigurable Intelligent Surfaces

In this article, we present an equivalence principle-based hybrid method to model wave propagation in wireless communication channels with reconfigurable intelligent surfaces (RISs). Our method computes received signal strength (RSS) in RIS communication channels, considering all practical factors that influence them, such as mutual coupling of RIS cells, edge effects, and multipath propagation toward and from the RIS. We show that the accuracy of our method is comparable with that of full-wave analysis, both near and far from the RIS, through simple examples that are manageable by the finite-element method. Also, we experimentally validate it by comparing simulated and measured data for an indoor radio environment with an anomalous reflection metasurface.