具有阻抗匹配层的宽带纵向振动压电换能器设计

Design of wide-band longitudinal mode piezoelectric transducers with impedance matching layers

本文研究纵向振动压电换能器的频带展宽问题．在复合棒纵向换能器的辐射端加上适当材料的阻抗匹配层，可以使其工作在非单谐振状态下．在单层阻抗匹配层的情况下，合理地选择匹配层的厚度可以调整其谐振点之间的位置，从而改善换能器的辐射特性．本研究结果表明，对于机械品质因素 Ｑｍ＝６，发射响应带宽△ｆ＝４ｋＨＺ的纵向振子，采用四分之一波长厚度的匹配层，在不降低发射响应的条件下，可展宽频带一倍以上。

The article study widening band of longitudinal mode piezoelectric transducers. The non-single resonance characteristics appear by forming proper impedance matching layers on the radiative surface of longitudinal mode piezoelectric transducer. The places of resonance points can be adjusted, and the radiated characteristic of transducer with single matching layers was improved by choosing the length of matching layer reasonably. The research on the transducer having mechanical quality factor Qm=6, bandwidth of transmitting sensitivity △f=4kHz presents that, using quarter matching layer, two times bandwidth was achieved in same transmitting sensitivity.