一种微加工超声传感器的设计

Design of Capacitive Microfabricated Ultrasonic Transducer

电容式微加工超声传感器(cMUT)是近年来出现的新型器件,具有高灵敏度、频带宽和机电转换效率高等优点,大有取代传统的压电式超声传感器之势.介绍了cMUT的基本结构和工作原理,提出了一种新型传感器结构.针对此结构建立了两个有限元模型,通过对其中的一个三维模型进行模态分析得知,cMUT可工作在一阶频率处,其振动频率为4.582 MHz;利用另一个三维模型进行静态和谐波分析,得出传感器的塌陷电压为213 V,当对cMUT施加45 V直流偏置电压和1.6 V交流电压时,其谐振频率为4.147 MHz,薄膜的最大位移为0.447μm.

Capacitive microfabricated ultrasonic transducer（cMUT） has emerged in the last decade, it has the potential to replace conventional piezoelectric transducer in various aspects, such as sensitivity, bandwidth and transduction efficiency. The structure and principle of cMUT were described. A new kind of structure was presented, and two finite element models for the structure were developed. First, to predict the operation frequency of the cMUT, a 3D solid model was established for modal analysis, it was shown the cMUT could work at the first order frequency of 4. 582 MHz. Then, another 3D solid model was established for static and harmonic analyses, the results of simulation demonstrated the collapse voltage of the transducer was 213V, when the cMUT was drived by biased 45 V DC and 1.6 V AC, its resonant frequency was 4. 147 MHz and maximum membrane displacement was 0.447μm.