Aerial Ultrasound Source by Stepped Circular Vibrating Plate

Abstract

For the industrial application of aerial ultrasound, a sound source has to generate high intensity ultrasound. As the sound sources developed are rectangular or circular vibrating plates, a dual beam directional pattern is usually obtained. The vibration figure of these plates is flexural so that vibration nodes are produced on them, and the phase of radiated ultrasound from adjoining vibration loops is a counter phase. In this paper, a height of a half wavelength at the frequency of around 20 kHz of a convex section was put on a circular vibrating plate between vibration nodes. The radiated ultrasound was adjusted to be in phase so that a single beam directional pattern was obtained on the center axis of a radiated field, and higher maximum sound pressure was obtained than that of the circular vibrating plate.