中文摘要：

阶梯型圆盘辐射体因其大辐射面积、高辐射效率等优点在大功率超声领域获得了广泛的应用．由于阶梯圆盘的频率方程中包含特殊函数，且方程数目多，利用数值计算方法进行编程求解，很是耗时费力．通过对基底盘、阶梯盘和厚度等同于基底与阶梯厚度之和的平圆盘的大量计算，发现在同频率条件下，单节线阶梯圆盘的半径和节线半径与厚度为中凸部分（基底与阶梯厚度之和）的平圆盘的相应值比较接近，这就为多节线阶梯圆盘复杂设计程序中参数初值的快速确定提供了一种方法．

英文摘要：

A stepped circular plate radiator for its big radiating area and advantages of high radiation efficiency has been widely used in high - power ultrasonic field. Because of the frequency equations of a stepped circular plate containing special functions, in addition, picking out the optium solution by applying frequency equations from among the numerous solutions is very time - consuming. Through a lot of calculation concerning the basal fiat circular plate, stepped circular plate and the flat plate which its thickness equates to basal thickness plus the one of the convex plate in this paper, we have discovered that the radius and the nodal radius of single stepped plate is very close to the fiat plate which its thickness equates to basal thickness plus the one of the convex plate at the same resonant frequency. This will provide a method of determination of the initial parameter val- ue in complex design program of a stepped circular plate.