The Effect of Electrical Impedance Matching on the Electromechanical Characteristics of Sandwiched Piezoelectric Ultrasonic Transducers.

Yuan Yang,Wenqing Yao,Lei Zhang,Xiaoyuan Wei

doi:10.3390/s17122832

Abstract

For achieving the power maximum transmission, the electrical impedance matching (EIM) for piezoelectric ultrasonic transducers is highly required. In this paper, the effect of EIM networks on the electromechanical characteristics of sandwiched piezoelectric ultrasonic transducers is investigated in time and frequency domains, based on the PSpice model of single sandwiched piezoelectric ultrasonic transducer. The above-mentioned EIM networks include, series capacitance and parallel inductance (I type) and series inductance and parallel capacitance (II type). It is shown that when I and II type EIM networks are used, the resonance and anti-resonance frequencies and the received signal tailing are decreased; II type makes the electro-acoustic power ratio and the signal tailing smaller whereas it makes the electro-acoustic gain ratio larger at resonance frequency. In addition, I type makes the effective electromechanical coupling coefficient increase and II type makes it decrease; II type make the power spectral density at resonance frequency more dramatically increased. Specially, the electro-acoustic power ratio has maximum value near anti-resonance frequency, while the electro-acoustic gain ratio has maximum value near resonance frequency. It can be found that the theoretically analyzed results have good consistency with the measured ones.

Highlights

Sandwiched piezoelectric ultrasonic transducers are widely applied in areas such as non-destructive testing (NDT) [1], structural health monitoring (SHM) [2,3], energy harvesting [4,5], piezoelectric motors, ultrasonic cleaning, and welding, etc. [6,7,8]
The effect of electrical impedance matching (EIM) networks on the electromechanical characteristics of sandwiched piezoelectric ultrasonic transducers is investigated in depth in time and frequency domains on the basis
The effect of EIM networks on the electromechanical characteristics of of the PSpice models of single sandwiched piezoelectric ultrasonic transducer and the pitch-catch sandwiched piezoelectric ultrasonic transducers is investigated in depth in time and frequency setup, respectively

Summary

Introduction

Sandwiched piezoelectric ultrasonic transducers are widely applied in areas such as non-destructive testing (NDT) [1], structural health monitoring (SHM) [2,3], energy harvesting [4,5], piezoelectric motors, ultrasonic cleaning, and welding, etc. [6,7,8]. The input electrical impedance of the sandwiched piezoelectric ultrasonic transducers is usually relatively larger. There is an electrical impedance mismatch between piezoelectric transducers and some interface devices mainly including signal generators, data acquisition devices, which usually have an internal impedance of. On the basis of the Butterworth-Van-Dyke (BVD) model [9], it can be seen that piezoelectric transducers are primarily capacitive when they are operated at resonant frequencies. When the input electrical impedance shows capacitive or inductive, the electrical power is obviously less than that for the resistive electrical impedance. This can lead to much reactive power. The reactive power is quietly harmful to piezoelectric transducers and electrical power sources. Given the above-mentioned considerations, an electrical impedance matching (EIM) network is urgently demanded

Methods

Results

Discussion

Conclusion