The electro-mechanical behaviour of flexural ultrasonic transducers

Steve Dixon,Christopher Wells,Andrew Feeney,Michael Ginestier,Lei Kang,George Rowlands

doi:10.1063/1.4984239

Steve Dixon, Christopher Wells + Show 4 more

Open Access

https://doi.org/10.1063/1.4984239

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Journal: Applied Physics Letters	Publication Date: May 29, 2017
Citations: 21	License type: cc-by

Affiliation: University of Warwick

Abstract

Flexural ultrasonic transducers are capable of high electro-mechanical coupling efficiencies for the generation or detection of ultrasound in fluids. They are the most common type of ultrasonic sensor, commonly used in parking sensors, because the devices are efficient, robust, and inexpensive. The simplest design consists of a piezoelectric disc, bonded to the inner surface of a metal cap, the face of which provides a vibrating membrane for the generation or detection of ultrasonic waves in fluids. Experimental measurements demonstrate that during the excitation of the piezoelectric element by an electrical voltage, there are three characteristic regions, where the frequency of the emitted ultrasonic wave changes during the excitation, steady-state, and the final decay process. A simple mechanical analogue model is capable of describing this behaviour.

Highlights

Flexural ultrasonic transducers are capable of high electro-mechanical coupling efficiencies for the generation or detection of ultrasound in fluids
We describe the general response of these ultrasonic sensors, focusing on readily available sensors operating at 40 kHz, the findings apply to sensors operating at higher frequencies
We describe an efficient and simple way to accurately measure the resonant frequencies of flexural sensors, and explain the effects of driving these sensors at frequencies away from their resonant frequency

Summary

Introduction

Flexural ultrasonic transducers are capable of high electro-mechanical coupling efficiencies for the generation or detection of ultrasound in fluids. Experimental measurements demonstrate that during the excitation of the piezoelectric element by an electrical voltage, there are three characteristic regions, where the frequency of the emitted ultrasonic wave changes during the excitation, steady-state, and the final decay process.

Results

Conclusion