Corrections to "Reradiation and Scattering from a Reconfigurable Intelligent Surface: A General Macroscopic Model"

A macroscopic model for Reconfigurable Intelligent Surfaces (RIS) was proposed in [1]. The model overlooks the RIS microscopic structure to directly address the wave transformation it realizes through a "spatial modulation coefficient" and can be applied to both metasurfaces and reflectarray-based implementations. It accounts for multiple reradiation modes and diffuse scattering. The discretized, antenna-array-like version of the model, described in [1, Section III.B], essentially mimics a reflectarray-based model with half-wavelength element spacing, thereby resulting in an electromagnetically consistent scattering-matrix model. In [1], the model is compared to an integral formulation and validated numerically. The spatial modulation coefficient has subsequently been utilized in additional research to develop a fully ray-based model, as detailed in [2].