Wireless power transfer through metal is challenging because conventional electromagnetic methods fail due to the Faraday shielding effect. Acoustic power transfer (APT) offers a promising alternative, as acoustic waves can propagate efficiently through metals. The thesis investigates the theoretical foundations and modelling of a through-metal APT system, supported by experiments and the development of novel wireless through-metal sensing applications.
We studied the influence of acoustic medium properties, piezoelectric material types, and temperature on system performance. The work explores 1-3 composite and hard PZT ceramics, with a key contribution being a novel method to determine the complete reduced matrix of hard PZT using a single disc sample.
Delivering power alone does not solve the communication problem, as protocols like Bluetooth and WiFi also fail through metal. To address this, we validated passive acoustic sensing and acoustic communication methods. We demonstrated passive temperature sensing using time-of-flight measurements and resonant frequency tracking of brass resonators. These approaches require no electronic components inside the metal enclosure, making them suitable for high-temperature environments. Finally, we built prototypes that simultaneously transfer power and data through a metal wall using a shared acoustic link.