The effect of reflections on the performance of an acoustic energy transfer system

The performance of an acoustic energy transfer (AET) system, defined as the ratio of electrical output to input power, is affected to a large extent by reflections. Their effect is examined in this paper. A finite element model is created to model reflections in a typical AET system, of which the simulation results are compared to measurements. The results show that modelling reflections is possible, but the transducer model is extremely critical for accurate prediction. The effect of the addition of horns to the transducers was examined by means of both experiments and finite element modelling. Although the experiments showed that the horns did not reduce the reflections, it was found that the decline in performance as a function of distance is significantly lower. Moreover, the energy transfer efficiency was found to be much higher than in the experiments with the hornless transducers.