Electromagnetics-Based RIS Channel Model with Near-Field Accuracy Improvement

An enhanced electromagnetics-based channel model of communication between two devices via reconfigurable intelligent surface (RIS) that enables closer placement of the devices to the RIS is described. This improvement is achieved by decomposing the communication paths between the RIS and the devices into individual paths for each RIS element. Key features include the use of commercial simulation software for device characterization, physical-level modeling of RIS inter-element coupling, fast device linking using the scattering matrix formalism, and easy emulation of fading or blockage. The model is implemented as a MATLAB function and additionally offers higher-order interpolation for improved accuracy.