Evaluation of the shielding effects on printed-circuit-board transformers using ferrite plates and copper sheets

Abstract

This paper presents an effective shielding technique and a simple structure for printed-circuit-board (PCB) transformers. Performance of PCB transformers using the proposed shielding technique is evaluated using thin ferrite plates and copper sheets. Without affecting the transformer energy efficiency, the shielding method under investigation can achieve 28 dB shielding effectiveness (SE), which is much higher than the SE (about 4 dB) obtained by shielding the transformer windings with only two ferrite plates. The proposed PCB transformer structure is very simple and has high energy efficiency (90%) for Megahertz operation.

Magnetic Resonance for Wireless Power Transfer [A Look Back]

“…In 2012, there was a suggestion of using a conducting surface and a layer of magnetic material to shape the magnetic field [39] in order to avoid lossy objects. It should be noted that the use of a double-layer electromagnetic shield comprising a layer of conducting material and a layer of soft magnetic materials for confining the magnetic field was previously described in 2002 [40] and [41]. If weak magnetic field of frequency close to 7 MHz could induce health hazards, not only lossy objects but also human bodies should be shielded from such magnetic field.…”

Wideband shielding effectiveness of laminated sheet using copper and magnetic materials

“…The authors focus on laminated sheets to solve the above problem. Laminated sheets which are composed of copper and magnetic materials are expected to obtain higher shielding effectiveness than that of the metallic materials [5,6]. However, optimum conditions of laminated sheets for obtaining wideband shielding effectiveness from LF to HF bands were not reported.…”

Magnetic shielding structure optimization design for wireless power transmission coil

“…The first aspect concentrates on internal parameters design, such as coil structure optimization and the source structure redesign while the second research direction pays more attention to external materials addition, for example, the magnetic shielding material. [12][13][14][15][16] The first aspect has been widely studied, [17][18][19] and it is difficult to further improve the performance of WPT. On the other hand, special materials are not always effective for performance improvement and some of the materials have specific using requirements.…”