Circular stepped-plates are often chosen to generate continuous waves in air due to their transmission efficiency, directive radiation patterns and capability to generate high-intensity airwave emission. Such features can be suitable for an acoustic radiator intended for the generation of harmonic radiation force, if the narrow bandwidth of the piezoelectric power transducer is not an obstacle to the application. This force has been used as the excitation source in noncontact modal analysis of mechanical devices, since it offers some advantages over the traditional impact method and the use of shakers. In this study, a directional stepped-plate ultrasonic device driven by a bolt-clamped Langevin-type transducer is used to excite the first flexural mode of a clamped-free beam by means of harmonic radiation force. The harmonic component was generated using an amplitude-modulated electrical input signal. The radiator design was done by solving a parametric optimization problem of finding a plate with the desired vibrational behavior using the genetic algorithm. Finite element analysis was used to obtain the dynamic behavior of the device and the airwave propagation was modeled using linear acoustic theory. Modal and harmonic analyses were conducted to obtain some of the electroacoustic parameters of the transducer. The acoustic field generated by the prototype is estimated by solving the Rayleigh integral and the obtained results are compared to experimental measurements.

由于圆形阶梯板的传输效率、定向辐射模式和产生高强度空气波发射的能力，通常选择圆形阶梯板在空气中产生连续波。如果压电功率换能器的窄带宽不是应用的障碍，则这些特征可以适合用于产生谐波辐射力的声辐射器。该力已被用作机械设备非接触模态分析中的激励源，因为它比传统冲击方法和振动台的使用具有一些优势。在这项研究中，由螺栓夹紧的朗之万型换能器驱动的定向阶梯板超声装置被用来通过谐波辐射力来激发自由夹紧梁的第一弯曲模式。谐波分量是使用调幅电输入信号生成的。散热器设计是通过解决参数优化问题来完成的，即使用遗传算法找到具有所需振动行为的板。使用有限元分析来获得设备的动态行为，并使用线性声学理论对空气波传播进行建模。进行模态和谐波分析以获得换能器的一些电声参数。通过求解瑞利积分来估计原型产生的声场，并将获得的结果与实验测量结果进行比较。