Wireless Power Transfer Based on Spider Web–Coil for Biomedical Implants

A biomedical implant (BMI) is a device that allows patients to monitor their health condition at any time and obtain care from any location. However, the functionality of these devices is limited because of their restricted battery capacity, such that a BMI may not attain its full potential. Wireless power transfer technology–based magnetic resonant coupling (WPT–MRC) is considered a promising solution to the problem of restricted battery capacity in BMIs. In this paper, spider web coil–MRC (SWC-MRC) was designed and practically implemented to overcome the restricted battery life in low–power BMIs. A series/parallel (S/P) topology for powering the BMI was proposed in the design of the SWC-MRC. Several experiments were conducted in the lab to investigate the performance of the SWC-MRC system in terms of DC output voltage, power transfer, and transfer efficiency at different resistive loads and distances. The experimental results of the SWC-MRC test revealed that when the Vsource is 30 V, the DC output voltage of 5 V can be obtained at 1 cm. At such a distance (i.e., 1 cm), the SWC-MRC transfer efficiency is 91.86% and 97.91%, and the power transfer is 13.26 W and 23.5 W when 50- and 100-Ω resistive loads were adopted, respectively. A power transfer of 12.42 W and transfer efficiency of 93.38% were achieved at 2 cm for when a 150-Ω resistive load and a Vsource of 35 V were considered. The achieved performance was adequate for charging some BMIs, such as a pacemaker.