Acoustic wireless power transfer with receiver array for enhanced performance

Achieving wireless power transfer through airborne acoustic/ultrasonic waves has been previously shown to be a feasible alternative when the charging distance is above several times the transducer size. In order to further increase the receiver efficiency, constructing the receiver out of an array of transducer elements to increase the receiver effective area is desirable. In this work, a study on the power combining through series or parallel interconnections of the receiver elements is done to understand the benefits of both cases and the conditions required to maximize receiver efficiency, with measurements and modeling results presented. With a seven element receiver array, a factor of 4.25 increase in receiver efficiency was achieved compared to only using the receiver center transducer.