Theoretical study on the characteristics of sound field radiated by a Gaussian rectangular transducer

Abstract

Generally, the surface vibration velocity amplitude of a conventional rectangular acoustic probe is the same. Because of strong interference, the radiated sound field in the near-field is extremely uneven, and radiation side lobes appears in the far field, which are not conducive to its application in ultrasonic technology. A rectangular acoustic transducer with Gaussian vibration velocity distribution on the acoustic radiation surface can reduce or avoid the near field of extreme inhomogeneity and far-field side-lobe. So it can be used in medical ultrasound diagnosis and industrial nondestructive testing and can obtain better effect. In this paper, the radiated sound field of a rectangular transducer with Gaussian distribution of surface vibration velocity is calculated, theoretically. The medium is isotropic without attenuation. The center of the rectangular transducer is assigned as the origin of coordinates. And the plane of the surface is as XOY surface. Then the coordinate system is established. Using Rayleigh integral method, the calculation of the radiation sound field is carried out. Discussion of the acoustic field distribution including on the beam axis and the far field is carried out. It is found that the sound field distribution on the beam axis is closely related to the parameters of the transducer surface. The oscillation of the sound pressure on the beam axis can be avoided by adjusting the parameters. There is no side lobe in the far field. The study of this paper can provide a theoretical suggestion for the application of Gaussian rectangular transducer.