Magnetic sensor based on surface acoustic waves for biomedical applications

In response to the rising prevalence of cardiovascular diseases and strokes, the development of non-invasive diagnostic techniques suitable for continuous monitoring is a major challenge. Magnetocardiography (MCG) enables contactless measurement of the magnetic fields generated by the heart, but requires highly sensitive sensors due to the extremely low signal amplitude. Existing sensors are often bulky or rely on wired connections. 

In this context, surface acoustic wave-based magnetic sensors (MSAW) represent a promising solution. These sensors are compact, passive (battery-free), and can be interrogated remotely (wireless). The main objective of this work is to enhance the magnetic field sensitivity of MSAW devices while accounting for temperature variations, aiming to develop a thermally compensated sensor. 

Two designs are proposed to achieve these objectives. They aim to improve magnetic field sensitivity through two complementary strategies: increasing the thickness of the magnetosensitive material and raising the operating frequency. At the same time, two temperature compensation methods are implemented: structural compensation, by adjusting the thicknesses of the materials comprising the sensor, and compensation via differential calculation, using propagation paths functionalized by different materials.

Reviewers
Mrs. Hamida HALLI ABBAS — Associate Professor (HDR), University of Bordeaux
Mr. Nicolas TIERCELIN — Research Director, CNRS - IEMN

Examiners
Mr. Pascal NICOLAY — Professor, Carinthia University of Applied Sciences, Austria
Mr. Thomas HAUET — Associate Professor (HDR), University of Lorraine
Mr. Abdelkrim Talbi — Professor, Centrale Lille

PhD Supervisor
Mr. Omar ELMAZRIA — Professor, University of Lorraine

Co-supervisor
Mrs. Cécile FLOER — Associate Professor, University of Lorraine