Intermediate layer to improve the performances and the frequency control of acoustic power transfer systems

Powering remote sensor nodes placed behind walls without drilling holes is of great interest for many industrial processes and applications. Acoustic power transfer using two piezoelectric transducers placed on both sides of the wall is a proven technology to answer this need. In this paper, we demonstrate that the use of an intermediary layer placed between the emitter and the wall results in a strong increase of the transmitted power: experimentally, the transmitted power is multiplied by two for the same driving voltage. We also show that intermediary layers strongly simplify the identification and the control of the optimal excitation frequency.