A 6.78-MHz Robust WPT System with Inductive Link Bandwidth Extended for cm-Sized Implantable Medical Devices

Area of Science:

• Biomedical Engineering
• Electrical Engineering
• Medical Devices

Background:

• Wireless Power Transmission (WPT) is crucial for powering Implantable Medical Devices (IMDs).
• Existing WPT systems face challenges with efficiency and power delivery to small implants.
• Robustness against misalignment is critical for reliable in-vivo operation.

Purpose of the Study:

• To develop a novel technique for designing a robust inductive link for cm-sized IMDs.
• To extend the bandwidth of the WPT link to maximize Power Delivered to Load (PDL) and Power Transfer Efficiency (PTE).
• To validate the proposed WPT system through in-vivo experiments under various conditions.

Main Methods:

• Design and circuit implementation of a robust inductive WPT link.
• Utilizing circular Transmitter (Tx) and Receiver (Rx) coils with specific diameters (5 cm and 2.5 cm).
• Experimental validation including tests under three misalignment conditions and varying distances (1.5-4 cm).

Main Results:

• Achieved Power Transfer Efficiency (PTE) ranging from 0.82% to 25.7%.
• Delivered Power to Load (PDL) achieved between 44.4 mW and 720 mW.
• Demonstrated robustness of the inductive link through misalignment experiments.

Conclusions:

• The proposed technique enables the design of robust inductive links for WPT to cm-sized IMDs.
• Bandwidth extension effectively maximizes PDL and PTE.
• In-vivo validation confirms the system's reliability and performance under challenging conditions.