声压增强型压电微机械超声换能器

压电微机械超声波换能器(PMUT)在医疗成像、测距、无损检测和流量感应等领域有着广阔的应用前景。针对传统结构PMUT输出声压较低的问题，该文提出了一种集成亥姆霍兹谐振腔的声压增强型PMUT。构建了声压增强型PMUT的等效电路模型，模拟并对比分析了声压增强型PMUT和传统PMUT的轴上声压。结果表明在70 kHz谐振频率下，声压增强型PMUT沿z轴的输出声压比传统的PMUT沿z轴的输出声压高约42%。测距结果表明，集成了亥姆霍兹谐振腔的PMUT最远测距能力达到2.62 m,比传统结构的PMUT提升了27%。这种结构为PMUT在提升测距能力和拓宽应用场景方面提供了一种新思路。

Sound Pressure Enhanced Piezoelectric Micromechanical Ultrasound Transducer

The piezoelectric micromechanical ultrasonic transducers (PMUTs) have promising applications in medical imaging, ranging, nondestructive testing and flow sensing. To address the problem of low output sound pressure of conventional structured PMUTs, this paper proposes a sound pressure enhanced PMUT with an integrated Helmholtz resonant cavity. The Helmholtz resonant cavity structure recovers and amplifies the backward sound pressure of the PMUT and radiates the pressure through the central aperture to the front, allowing the frontal output sound pressure to be enhanced. The equivalent circuit model of the sound pressure enhanced PMUT is established, and the on-axis sound pressure of the sound pressure enhanced PMUT and the conventional PMUT is simulated and compared. The results show that at a resonant frequency of 70 kHz, the output sound pressure along the z-axis of the sound pressure-enhanced PMUT is approximately 42% higher than that of the conventional PMUT. The results of the ranging experiments show that the PMUT with an integrated Helmholtz resonant cavity has a maximum ranging capability of 2.62 m, which is a 27% improvement compared to the conventional structure of the PMUT. This structure provides a new idea for PMUT to improve ranging capabilities and broaden application scenarios.