numerical analysis on the effect of focusing metasurfaces in energy harvesting applications

The aim of this thesis work is to describe Metasurfaces for Wireless Energy Harvesting (WEH) applications. The goal is to introduce newly conceptualized designs for focusing EM radiation into a predefined region with the aim of increasing the overall energy harvested by the system. The methodology behind the design of Metasurfaces for focusing applications will be described, with particular emphasis on PGMS (Phase-Shift Metasurfaces), together with their interaction with the freely propagating signals to obtain the desired ranging capability. Two models have been proposed, operating at 2.45 GHz, for increasing the received power and therefore enhancing the overall efficiency of a WEH link. The structures, completely passive, present a symmetric topology composed by concentric rings: the first one (3 rings model) allows to precisely focus the power at 20 cm of distance with 6.6 dB gain, while the second one (2 rings model) focuses the power at 2.5 cm with a gain 3 dB with less precision but proposing a compact design. The results have been obtained considering a link of 1 m where the transmitter and receiver are planar patches and it has been demonstrated how the presence of the metasurfaces increases the received power level, highlighting them as one of the most promising solutions for WEH applications.