Power Efficiency Calculation of Acoustic Energy Transmission by a Stepped-Plate Radiator

One performance measure of in-air ultrasonic radiators, such as wireless power transmission, is the power efficiency of the transducers. The efficiency of most in-air acoustic radiators is low, even at ultrasonic frequencies; however, a large radiating plate with steps introduced by Gallego-Juarez et al., can provide efficient radiation. Their in-air acoustic radiator consists of a Langevin transducer for wave excitation, a mechanical amplifier, and a stepped plate with a large radiating area. This study describes a design processing technique for a stepped-plate radiator developed for optimum energy transmission at the target point in air. The total efficiency required to transfer the acoustic energy was divided into three categories, and the design parameters of each category were calculated to maximize the efficiency. This design technique allows optimum acoustic radiation efficiency and maximum acoustic energy transmission depending on various acoustic energy transfer conditions.