Design and acoustic characterization of limited diffraction ultrasonic devices

Abstract

Limited diffraction ultrasonic transducers are devices that have a large depth of acoustic field without important effects of diffraction, which make them optimal in applications of medical images, among others. This report details how this special type of piezoelectric device was designed by means of a simple technology using three electrodes in the form of concentric rings in both faces of a ferroelectric ceramic disk, which were used to apply a profile of non-homogeneous polarization. Once designed, the radiation fields emitted by these resonators were characterized experimentally by electro-acoustic and acousto-optic techniques and were compared with those emitted by conventional devices. As shown in the experimental characterizations, ultrasonic transducers with optimal properties for use in medical applications such as good collimation of the ultrasound beam, high lateral resolution, as well as little effects of diffraction were obtained.

Application of ultrasound in medicine part ii: the ultrasonic transducer and its associated electronics

“…Thus, only piezoelectric generation is used in medical applications; in order to do this, it is necessary to use a particular type of piezoelectric material which is able deliver optimum collimation of its US light beam, optimum lateral image resolution and small diffraction effects [1].…”