超声换能器辐射特性的优化*

匹配层和背衬层是换能器的重要组成部分,对换能器特性有重要影响。针对发射型换能器,基于有/无匹配层和空气/树脂背衬两种条件组合,该文研究了匹配层与背衬层对换能器辐射特性的影响。结果表明,负载材料为水时,空气背衬换能器相较于树脂背衬换能器声能辐射效率更高；匹配层可以提高换能器的主瓣能量,抑制旁瓣能量及旁瓣数量。因此,针对发射型换能器的设计,背衬材料的选择应遵循与压电材料的阻抗差异越大越优的原则；匹配层的合理设计不仅可以提高超声换能器的声能辐射效率,还可以提高主瓣旁瓣峰值比,使声能更集中。

Optimization of radiation characteristics of ultrasonic transducer

The matching layer and backing layer are important components of the transducer, which have important influence on the characteristics of the transducer. In this paper, the effects of matching layer and backing layer on radiation characteristics of transmitting transducer are studied based on the combination of two conditions: with/without matching layer and with air/resin backing layer. The results show that the acoustic radiation efficiency of air backed transducer is higher than that of resin backed transducer when the load material is water. The matching layer can improve the main lobe energy of the transducer and inhibit the side lobe energy and the number of side lobes. Therefore, for the design of transmitting transducers, the selection of backing materials should follow the principle of the greater the impedance difference between piezoelectric materials and the better; The rational design of matching layer can not only improve the radiation efficiency of ultrasonic transducer, but also improve the peak ratio of main lobe and side lobe, so that the sound energy is more concentrated.