Analysis and Design Considerations of Nonhomogeneous Metamaterial for Low-Frequency Magnetic Field Shielding

This work aims at realizing a system which, inserted in a wireless power transfer (WPT) charging system for low-frequency applications, is able to shield the magnetic field over a desired region of interest while preserving the WPT system efficiency. The shielding of the magnetic field is achieved by using a metamaterial, also called metasurface in its 2-D realization. The metasurface consists of a matrix of resonators, or unit cells, (a square 5 × 5 surface), and in the realization presented here, it is passive, so it is activated by inductive coupling with the WPT system it is designed to work with. Very few works are present in the literature relative to low-frequency magnetic shielding achieved by the adoption of homogeneous metamaterials. This work is dedicated to the design and realization of a nonhomogeneous metasurface, with the aim of showing that nonhomogeneity can lead to better performances in terms of shielding effectiveness.