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

• Published in: IEEE wireless communications letters Vol. 10; no. 5; pp. 938 - 942
• Main Authors: Gradoni, Gabriele, Di Renzo, Marco
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.05.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE); IEEE comsoc
• Subjects: Electronics; Engineering Sciences; Load modeling; Mutual coupling; New technology; Receiving antennas; Reconfigurable intelligent surfaces; Surface impedance; Transmitting antennas; Unit cell; Wireless; Wireless communication; Wireless networks; Wires
• ISSN: 2162-2337; 2162-2345
• DOI: 10.1109/LWC.2021.3050826

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.