Bessel beam ultrasonic transducer: Fabrication method and experimental results

Abstract

We report experimental results from a first-of-a-kind ultrasonic transducer that generates a beam with a Bessel function profile. Using a technique of nonuniform poling, an axially symmetric Bessel function pattern is ‘‘polarized into’’ a piezoelectric ceramic element. The resulting circular-disk transducer has the usual full-plating electrode configuration, but produces an ultrasonic beam with a radial displacement profile approximating that of the Bessel function J0 (r), both in amplitude and in phase. The radiation field of a 1-in.-diam, 2.25 MHz Bessel transducer mapped out with a point probe shows good agreement with calculated results using a Gauss-Hermite model. Bessel transducers are of particular interest in attempts to achieve ‘‘diffractionless’’ beams.

Large Depth of Field Pseudo-Bessel Beam Generation With a RLSA Antenna

“…In optics and acoustics, several techniques for launching Bessel beams exist [5, and references therein], [6]- [9]. A few have been recently suggested in the millimeter-wave range [10]- [14].…”

Ultrasonic transducers with Bessel function distribution of vibrational amplitude on their surfaces

“…The frequency of these vibrations is determined by the formula (4) where c = wave velocity in the liquid a = tube radius 1 = tube (ring) length. The ring of piezoelectric ceramics is excited to vibration by alternating voltage applied to its electrodes- Fig.…”

“…To this end methods of the piezoelectric transducer electrodes apodization or the special process of piezoelectric ceramic polarization are applied. Such methods permit the obtainment of vibrational amplitude distributions that are only approximately equal to the Bessel function [3], [4]. Natural plate vibrations also exist with a distribution of vibrational amplitude in their resonance approximately equivalent to the Bessel function distribution [5].…”

Acoustic radiation force on a sphere in standing and quasi-standing zero-order Bessel beam tweezers

“…Furthermore, Bessel beams are self-healing ; if part of the beam is obstructed or distorted, the beam reconstructs itself after a characteristic propagation distance [39]. In the field of acoustics, such beams of limited diffraction have provided an attractive alternative to using Gaussian beams in a wealth number of applications [40][41][42][43][44][45][46][47][48].…”