Miniaturised wireless and battery-free systems for physiological monitoring and stimulation

Abstract

This thesis explores the development of miniaturised wireless and battery-free systems

for physiological monitoring and their possible applications in stimulation. It

addresses critical challenges in power delivery, energy harvesting, data communication,

device miniaturisation, lowering implantation potential risks, and improving

end-user comfort. This thesis includes a comprehensive literature review that establishes

the groundwork by identifying gaps and opportunities in the field. The

research introduces a high-bandwidth optical telemetry system for brain signal sensing,

providing a foundation for wireless monitoring technologies. This is extended

with a novel integration of optical telemetry and focused ultrasound power transfer,

creating a complete system for endovascular applications that eliminates long wires

and enhances clinical applicability, especially for fragile or pediatric patients. Further

contributions include a groundbreaking wireless power transfer system designed

to deliver sufficient energy directly to standard stents for monitoring and stimulation

applications without modifying its structure, achieving high efficiency and safety

compliance. The thesis also presents a novel sensing electrode for a wireless ambulatory

electroencephalogram (EEG) using hair-like conductive material implanted in

the skin layer, combining biocompatibility, comfort, aesthetics, and reliable signal

capture for long-term brain monitoring. Together, these advancements represent a

significant step forward in wireless and battery-free biomedical systems, offering practical

and innovative solutions for diagnostics, therapy, and research while addressing

key limitations in current technologies.