Mechanism and Optimization of Acoustic Power Transfer Systems

The need for bio-implantable devices is increasing day by day, however the charging of these devices is a major issue. As a result, wireless techniques of power transfer are developed recently to power these implants wirelessly and to eliminate the need of charging the batteries. In this paper, various techniques of power transfer viz., inductive-power transfer, RF power-transfer and acoustic power-transfer are compared first. The main focus in this paper is done on the acoustic power transfer methodology due to its advantages over inductive and RF power transfer. The mechanism and design challenges of the acoustic power transfer techniques are discussed. The acoustic pressure is calculated at different frequencies. Based on the various factors like transducer size, tissue-attenuation and Rayleigh-distance which are affected by the frequency; a best optimum frequency is chosen to compress the size of the device and augment the amplitude of the pressure wave. The simulations were done in MATLAB and COMSOL softwares. PZT-5H transducer is selected due to its high quality factor and high electromechanical coupling.