文献类型：期刊文献

英文题名：Cellular polypropylene piezoelectret air-coupled ultrasonic transducer for lamb wave defect detection

作者：Xu, Peng[1];Li, Haoliang[1];Li, Jian[1];Quan, Yi[2];Lyu, Yanfeng[1];Hu, Zheng[1,3];Fei, Chunlong[2];Qiu, Xunlin[1,3];Xiang, Yanxun[1];Xuan, Fu-Zhen[1]

机构：[1]East China Univ Sci & Technol, Sch Mech & Power Engn, Shanghai Key Lab Intelligent Sensing & Detect, Shanghai 200237, Peoples R China;[2]Xidian Univ, Fac Intergrated Circuit, Xian 710071, Peoples R China;[3]Shanghai Inst Aircraft Mech & Control, 100 Zhangwu Rd, Shanghai 200092, Peoples R China

年份：2026

卷号：409

外文期刊名：SENSORS AND ACTUATORS A-PHYSICAL

收录：;EI(收录号：20262320841783);WOS:【SCI-EXPANDED(收录号:WOS:001792572400001)】；

基金：Financial support from the National Natural Science Foundation of China (Nos. 12474467, 12025403, 12304511 and 52321002) and from Shanghai Gaofeng Project for University Academic Program Develop-ment is gratefully acknowledged.

语种：英文

外文关键词：Cellular polypropylene piezoelectret; Air-coupled ultrasonic transducer; Electrical impedance matching; Lamb wave non-destructive testing

摘要：The performance of air-coupled ultrasonic transducers is often constrained by inefficient electromechanical energy conversion, which severely limits their applicability in non-contact guided-wave sensing. In this study, a lightweight air-coupled ultrasonic transducer (ACUT) based on a cellular polypropylene (cPP) piezoelectret film is developed, and its operating performance is deliberately engineered through combined electrical impedance and bandwidth tailoring. Owing to its ultra-low acoustic impedance, high mechanical compliance, and pronounced thickness-mode piezoelectric activity, the cPP film enables inherently efficient acoustic coupling into air without the need for additional acoustic matching layers. To overcome the intrinsically high electrical impedance of the cPP ACUT, a It-type electrical impedance matching network is integrated, resulting in a narrowband operating regime centered at 220 kHz with an effective bandwidth of approximately 14 kHz (213-227 kHz). The electrical matching leads to an overall signal amplitude enhancement of approximately 42 dB compared with the unmatched configuration. As representative demonstrations, the cPP ACUT was applied to air-coupled excitation and reception of A0 Lamb waves in both PVC and aluminum alloy plates, and its versatility was further validated through comparative experiments with a commercial transducer. These results demonstrate that electrical impedance and bandwidth tailoring provides an effective transducer-level strategy for regulating the operating performance of piezoelectret-based air-coupled ultrasonic transducers, offering new design freedom for noncontact guided-wave sensing applications.