球面聚焦超声换能器的电声特性和测量方法的研究

Research on electroacoustic characteristics and measurements of spherically focusing transducer

研究介绍了圆形孔径的球面聚焦压电换能器的基本电声参数:输出声功率、辐射电导、电声效率、自由场发射电流(电压)响应、自由场电压灵敏度、有效面积、有效孔径、声焦距、声束宽度和阻抗(导纳)等电声特性及其测量方法,详细地论述了基于辐射力天平法和自易校准法的测量原理和方法,讨论了它们的内在联系。给出了换能器自易校准中的衍射修正系数和平均反射系数的公式、计算方法和系列数据图表。试验结果表明了测量原理和方法的合理性和可行性。

In the paper the electro-acoustic characteristics and measurement methods of spherically focusing transducer are studied. The relevant parameters and measurements including acoustic output power, radiation conductance, elec-tro-acoustic efficiency, free-field transmitting voltage (current) response, free-field voltage sensitivity, effective area, ef-fective aperture, acoustic focal length, beam width and electric impedance (admittance) are introduced. The methods based on RFB and self-reciprocity calibration are particularly described, and the relation between the two methods is discussed. The calculation methods with a set of table for the correction coefficients of diffraction and the average am-plitude reflection coefficients in self-reciprocity calibration are given. The results show that the measurement principles and methods are available and feasible.