论文部分内容阅读
超声压电换能器向空气中辐射超声波的主要缺点是效率低,这是由于压电材料的声阻抗与空气的声阻抗严重失配(差5个数量级)。有两种途径可提高换能器向空气中辐射声波的效率,一是采用多层结构的匹配技术,二是设计高、低声阻抗材料相组合的换能器。作者遵循后一种方法设计并制作了一种新的高效压电换能器。它是将压电圆环埋置在低阻抗的弹性材料(塑料或树脂)中而成的,如图1所示。
The main disadvantage of ultrasonic piezoelectric transducers radiating ultrasound into the air is their low efficiency due to a serious mismatch between the acoustic impedance of the piezoelectric material and the acoustic impedance of the air (by a factor of 5). There are two ways to improve the efficiency of the transducer radiating sound waves into the air. One is to use a multi-layer matching technique and the other is to design a transducer that combines high and low acoustic impedance materials. The authors followed the latter approach to design and fabricate a new high-efficiency piezoelectric transducer. It is a piezoelectric ring embedded in the low resistance of the elastic material (plastic or resin) made of, as shown in Figure 1.