This thesis focuses on the transmission of power and data through metal walls using acoustic waves. This technology will eventually enable the powering, reading and control of systems placed in areas enclosed in metal: pressure vessels, ship hulls and submarines, etc.
As electromagnetic waves are absorbed by metal, it is necessary to use acoustic waves to communicate data or power through metal walls. These are generated by piezoelectric transducers bonded to either side of the wall. Acoustic waves are poorly attenuated by metal, resulting in numerous reflections and multiple paths. It is therefore necessary to use multi-carrier communication techniques (e.g. OFDM), in order to achieve robustness and high throughput.
The aim of this thesis is to develop a robust technology demonstrator for remote powering and acoustic data communication through metal walls. This work will be based on advanced modeling of the acoustic channel to optimize the performance of the power and data transmission device. It will also involve developing innovative electronic building blocks to determine and maintain an optimum power transmission frequency, impacted by environmental conditions and typically by temperature.
The ultimate goal of this thesis will be the development and implementation of an OFDM communication system embedded in an FPGA and/or microcontroller to send sensor data through a metal wall of variable thickness. Limitations due to channel and electronic imperfections will lead to the invention of a large number of compensation methods and systems in the digital and/or analog domain. Work will also be carried out on the choice of piezoelectric transducers and channel characterization, in conjunction with the acoustic wave activities of the acoustic power transmission laboratory.