一、前言 以空气为辐射媒质的气介式超声换能器,以往大都采用圆管式、夹心式、弯曲式等几种形式。其中弯曲式换能器由于具有较低的辐射阻抗,容易向气体中辐射超声波,因而常被优先考虑使用。在弯曲式换能器中,由于结构方式及支撑条件的不同,灵敏度的差异相差甚大。结构简单,制作 I. INTRODUCTION The air-mediated ultrasonic transducer using air as the radiation medium has adopted several forms, such as circular tube type, sandwich type and bending type in the past. Bending transducers are often preferred due to their low radiation resistance and their ability to radiate ultrasound into the gas. In flexural transducers, the difference in sensitivity varies greatly due to the differences in the structure and the supporting conditions. Simple structure, production