Ultra-broadband near-field magnetic shielding realized by the Halbach-like structure

Abstract

With the great developments in electronic communication technology and miniaturized electromagnetic devices, near-field magnetic shielding has attracted much attention. However, for the widely used natural magnetic shielding materials, metal and ferrite, they have the unique limitations of large Ohmic loss and heavy weight, respectively. Although a compromise solution of the shielding layer may resort to the composite structure with metal and ferrite slabs, practical magnetic shielding with broadband, high efficiency, and ultra-thinness has remained a great challenge. In this work, inspired by the effective magnetic flux path established by the Halbach array, which is constructed by stacking permanent magnet in diverse directions, we propose a physical mechanism of local magnetic moment control in artificial structures, called the “Halbach-like structure.” We demonstrate the highly efficient and ultra-broadband near-field magnetic shielding in the Halbach-like structure with patterned metal and ferrite structures. By ingeniously designing the local magnetic moment, our structure not only provides an effective method for realizing high performance magnetic shielding but also paves the way to the other near-field controls, such as the wireless power transfer, wireless communications, and magnetic resonance imaging.