Iterative Method Based Optimization of Wireless Power Transfer for Biomedical Implants

Magnetic resonance coupling wireless power transfer (WPT) systems have gained increasing interest as an effective method for powering implantable medical devices (IMDs). Power transfer efficiency is a very important characteristic of WPT systems. It is characterized by the coupling and quality factors of the WPT coils. The maximum power transfer efficiency is obtained for high coupling and quality factors. It greatly depends on the geometrical parameters of the WPT coils. This paper presents an iterative procedure to design and optimize an implant coil restricted to a small size of 20mm at a distance of 30 mm, with an operating frequency of 13.56 MHz within the ISM frequency band. The proposed method aims to find the optimal geometrical parameters that maximize the power transfer efficiency. The designed coils give a high efficiency of about 83%. Finally, the finite element simulation with Ansys Maxwell 3D validates the obtained results.