Coil material and magnetic shielding methods for efficient wireless power transfer system for biomedical implant application

Abstract

In this paper, a passive shielding method is presented to minimize the magnetic field around the transmitting (Tx) and receiving (Rx) coil of wireless power transfer (WPT) system for biomedical implant application. Different conductive materials for coil construction, as well as dielectric materials for shielding, are being considered to improve WPT performance. Several cases of WPT coils have been examined using the simulation approach at 800 kHz and 6.78 MHz in the existence of a pacemaker casing with and without a magnetic shield. According to simulated results, it is found that high conductivity coils and high permeability shield materials are excellent materials for increasing the WPT system's efficiency. The results of the simulation method and physical measurement in Lab are validated using an analytical method. The efficiency obtained by using simulation method is very close to that obtained using the analytical method. The voltage gain obtained using an analytical and a simulation method at 800 kHz and 6.78 MHz is very close to the actual measurement in the lab. It is found that the WPT efficiency at 6.78 MHz is higher as compare to 800 kHz.