Innovative Approaches for Enabling Smart Electromagnetic Environments Through the Synthesis of Opportunistic Sources and Large-Size Modular EM Skins

In the context of the Smart ElectroMagnetic Environment (SEME) paradigm, this thesis presents two different low-impact and low-maintenance approaches for enhancing the connectivity of a wireless communication system, validating them in a set of test cases based on real-world application scenarios. Firstly, the Opportunistic Sources Synthesis (OSS) methodology is proposed as an Inverse Source approach to the realization of SEME in large urban scenarios. The methodology relies on the optimization of a primary illuminating source for generating opportunistic equivalent sources on the defined environment buildings, thus profitably exploiting the ElectroMagnetic (EM) phenomena happening among them to enhance the connectivity to users within the scenario. To enable the use of the OSS methodology in large-scale urban environments, a prediction technique, namely “Embedded-plus-Environment Patterns” (EPEP), is introduced and validated, and it is then considered as the basis of the OSS technique. Secondly, innovative methodologies for the realization of Modular ElectroMagnetic Skins (MEMS) are proposed, aiming at realizing large-size passive structures through inexpensive, easy to install elementary building blocks (“tiles”). The advantage of a modular approach for realizing EM skins is to be found in the possibility of installing otherwise unfeasibly-large structures to tailor the EM propagation in complex communication environments. In fact, MEMSs provide the advantage of a lower manufacturing and deployment complexity with respect to monolithic designs, thanks to the use of smaller, easy to build EM entities. The proposed methodology exploits the joint optimization of a set of tiles through a multi-objective Genetic Algorithm (GA), with the aim of providing the designer with a set of trade-offs between the performance enhancement of the communication system and the overall complexity of the MEMS structure. More specifically, to move towards standardization and affordability, the available configurations for the individual tiles have been limited to a finite amount of pre-defined layouts (or "alphabet"); this way, it is possible to synthesize large structures by properly choosing from a finite set of EMS building blocks, profitably exploiting the standardization during the manufacturing. process. Furthermore, methodologies have been developed for realizing modular EMS architectures through identical tiles, whose orientation can be mechanically adjusted to optimize the field scattered by the overall structure. In order to analyze and validate the proposed SEME architectures and the developed synthesis methodologies, an extensive numerical validation has been carried out in both indoor and outdoor realistic scenarios, considering, where possible, a direct comparison with the results achieved by similar technologies available in the literature.