Smart Electromagnetic Skins (SESs) are emerging as key enabling technologies for the evolution of wireless communication systems toward 5G, 6G, and beyond, where conventional links are strongly affected by high path loss and limited coverage. SESs are thin engineered structures designed to manipulate the propagation of electromagnetic waves, typically by redirecting incident fields through anomalous reflection. They are discretized into a large number of unit cells, whose geometry determines the overall electromagnetic response of the surface. In particular, passive SESs, based on resonant metallic patches printed on a dielectric substrate above a ground plane, represent an attractive solution due to their simplicity, low cost, and ease of integration.