Design of a Wireless Power Transfer System for Implantable Bio MEMS Microelectronic Devices: Application to the Pacemaker

Abstract

Implantable Medical Devices (IMDs) require a continuous power supply for sustainable operation. However, relying on conventional integrated batteries remains limited, with a lifespan generally not exceeding 10 years, which forces patients to undergo repeated and risky surgical procedures for replacement. To overcome this limitation, Wireless Power Transfer (WPT) via resonant inductive coupling emerges as a highly viable and sustainable solution. This study proposes the design, modeling, and practical development of high-efficiency inductive links tailored for biomedical implants. Operating at the international standard frequency of 13.56 MHz, the proposed system achieves an optimal trade-off between biological safety and transmission efficiency at the required depths. During the characterization of the electrical links, the work focuses on strict compliance with the miniaturized dimensions of the implant. A rigorous comparative analysis was conducted among three coil geometries: planar, solenoid, and hybrid configurations across various transfer distances. Experimental results demonstrated the superiority of the proposed hybrid planar-solenoid configuration (a 4.5 cm planar transmitter combined with a 1.5 cm miniaturized solenoid receiver) as the optimal solution. This hybrid architecture successfully secured a maximum power delivery of 73.125 mW in free space and maintained an effective power of 23.972 mW at a transmission distance of 1 cm. Furthermore, biological safety and electromagnetic permeability were successfully validated through experimental tests using human tissue as a direct biological barrier between the coils, ensuring efficient and uninterrupted power flow. The achieved results demonstrate strong alignment with contemporary global research, confirming the scientific and practical feasibility of the proposed hybrid concept for the development of a new generation of safe and sustainable electronic implants.