End-to-End Mutual Coupling Aware Communication Model for Reconfigurable Intelligent Surfaces: An Electromagnetic-Compliant Approach Based on Mutual Impedances

TL;DR

This paper presents a comprehensive electromagnetic-compliant end-to-end model for RIS-assisted wireless systems that incorporates mutual coupling effects among unit cells, enabling more accurate analysis and optimization of RIS performance.

Contribution

It introduces a novel EM-compliant, mutual coupling aware, end-to-end communication model for RIS that captures detailed physical interactions and unit cell responses.

Findings

Model accurately captures mutual coupling effects.

Enables EM-compliant optimization of RIS configurations.

Provides a one-to-one mapping between transmitter and receiver voltages.

Abstract

Reconfigurable intelligent surfaces (RISs) are an emerging technology for application to wireless networks. We introduce a physics and electromagnetic (EM) compliant communication model for analyzing and optimizing RIS-assisted wireless systems. The proposed model has four main notable attributes: (i) it is end-to-end, i.e., it is formulated in terms of an equivalent channel that yields a one-to-one mapping between the voltages fed into the ports of a transmitter and the voltages measured at the ports of a receiver; (ii) it is EM-compliant, i.e., it accounts for the generation and propagation of the EM fields; (iii) it is mutual coupling aware, i.e., it accounts for the mutual coupling among the sub-wavelength unit cells of the RIS; and (iv) it is unit cell aware, i.e., it accounts for the intertwinement between the amplitude and phase response of the unit cells of the RIS.