Yang Yuan, Wei Xiaoyuan, Zhang Lei, Yao Wenqing
Department of Electronic Engineering, Xi'an University of Technology, Xi'an 710048, Shaanxi, China.
Sensors (Basel). 2017 Dec 6;17(12):2832. doi: 10.3390/s17122832.
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.
为实现功率的最大传输，对压电超声换能器进行电阻抗匹配（EIM）至关重要。本文基于单夹心式压电超声换能器的PSpice模型，在时域和频域中研究了EIM网络对夹心式压电超声换能器机电特性的影响。上述EIM网络包括串联电容和并联电感（I型）以及串联电感和并联电容（II型）。结果表明，使用I型和II型EIM网络时，共振频率和反共振频率以及接收信号拖尾都会降低；II型使电声功率比和信号拖尾更小，而在共振频率处使电声增益比更大。此外，I型使有效机电耦合系数增加，II型使其减小；II型使共振频率处的功率谱密度增加更为显著。特别地，电声功率比在反共振频率附近有最大值，而电声增益比在共振频率附近有最大值。可以发现，理论分析结果与实测结果具有良好的一致性。
