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.
Lee, H., Kang, D. and Moon, M. (2009) A Micro-Machined Source Transducer for a Parametric Array in Air. The Journal of the Acoustical Society of America, 125, 1879-1893. http://dx.doi.org/10.1121/1.3081385
Barone, A. and Gallego-Juarez, J.A. (1971) Flexural Vibrating Free-Edge Plates with Stepped Thicknesses for Generating High Directional Ultrasonic Radiation. The Journal of the Acoustical Society of America, 51, 953-959. http://dx.doi.org/10.1121/1.1912944
Kinsler, L.E., Frey, A.R., Coppens, A.B. and Sanders, J.V. (2000) Fundamentals of Acoustics. 4th Edition, John Wiley & Sons, Inc, New York.
Sherman, C.H. and Butler, J.L. (2007) Transducers and Arrays for Underwater Sound. Springer, New York. https://doi.org/10.1007/978-0-387-33139-3