Smart Electromagnetic Skins for communication and localization systems = Smart Electromagnetic Skins for communication and localization systems

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. This thesis focuses on the design and analysis of a passive SES operating at 60 GHz for indoor communication scenarios. The first part of the work is devoted to the study of the unit cell, based on a square patch geometry, and to the investigation of different dielectric materials used as substrates. A detailed electromagnetic characterization of the unit cell has been carried out through full-wave simulations, analyzing its reflection properties as a function of the geometrical parameters and frequency of operation. This analysis has made it possible to compare several dielectric materials and identify the most suitable choice for operation at millimeter-wave frequencies. Based on the unit cell design, complete SES structures were developed by analyzing the required phase distribution across the surface and comparing it with the reflection phase curve obtained from simulations. This procedure allowed defining the arrangement of the unit cells, enabling the realization of a passive SES tailored for operation at 60 GHz in indoor scenarios. In the final part of the study, multiple SES configurations were designed for a simplified indoor environment. For each SES, the required phase distribution and the corresponding unit cell parameters were determined according to specified angles of incidence and departure. The complete surfaces were then modeled using CST simulations, which confirmed that the designed SESs successfully directed the mm-Wave signal toward the shadowed area, demonstrating the effectiveness of the proposed design approach. The results confirm the validity of the proposed methodology. Despite its passive and relatively simple configuration, the designed SES proves to be an effective tool for enhancing signal distribution in indoor environments, reducing blind spots and improving communication reliability. These findings highlight the potential of passive SESs as practical and efficient solutions for future wireless networks operating at millimeter-wave frequencies