In order to obtain an ultrasonic transducer (UT) with ultra-broad bandwidth (BW), a multilayer stairstep piezoelectric structure (MSPS) is designed and fabricated. Based on the theoretical computation, the relationship between the resonant frequency and thickness of the piezoelectric layer is obtained. The designed MSPS includes 15 layers from center to side, and its frequency range is 5-22 MHz. The finite element method (FEM) based PZFlex software is used to predict the performance of UT with the designed MSPS, and the thickness of each layer is optimized according to the simulation results to achieve the ultra-broad-BW UT. The UT with the designed MSPS is fabricated and systematically characterized. The measured results show that the fabricated UT has a center frequency of 10.54 MHz and a -6 dB BW of 121%, which agree well with the simulation results (11.75 MHz and 140%). The MSPS has significant potential in UT applications.

中文翻译：

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超宽带超声换能器多层阶梯压电结构设计


为了获得具有超宽带宽（BW）的超声换能器（UT），设计并制造了多层阶梯压电结构（MSPS）。根据理论计算，得到了谐振频率与压电层厚度的关系。设计的MSPS从中心到侧面包括15层，其频率范围为5-22 MHz。采用基于有限元法（FEM）的PZFlex软件对设计的MSPS进行UT性能预测，并根据仿真结果优化各层厚度，实现超宽带宽UT。具有设计的 MSPS 的 UT 已被制造并系统地表征。测量结果表明，所制作的UT的中心频率为10.54 MHz，-6 dB BW为121%，与仿真结果（11.75 MHz和140%）非常吻合。 MSPS 在 UT 应用中具有巨大潜力。