Analysis of Multi-Matching Layers of Ultrasonic Piezoelectric Transducer

• Main Authors: Ya-Wen Chu, 朱雅雯
• Other Authors: 宋家驥
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/83468923376898414598

碩士 === 國立臺灣大學 === 工程科學及海洋工程學研究所 === 93 === In recent years, the study of ultrasonic waves has found indispensable applications in the real world. In this thesis, we present the acoustic impedance matching result of the piezoelectric thin plate and the propagation medium when we increase the number of matching layers. To begin, we introduce the theory of piezoelectricity and explain the structure of the ultrasonic piezoelectric transducer. By extending the theory of transmission line, we find the impedances of the matching layer and find the impedances of each layer in conjunction with the maximally flat-top response. Finally, we conclude that the addition of the matching layers results in the widening of the transmission frequency for the piezoelectric transducer. An impedance matrix for the piezoelectric transducer can be derived from the piezoelectric wave equation which is called as the transmission matrix method. Using the transmission matrix method we obtain the mechanical and electric impedances of frequency response for the ultrasonic piezoelectric transducer. At the end of this paper, we show the simulation results of the multilayer matching structure of the piezoelectric transducer which can be helpful for designing the ultrasonic piezoelectric transducer.