Li Haoyong, Lv Jiaming, Li Delin, Xiong Chaoyu, Zhang Yihong, Yu Yiting
Opt Express. 2020 Jun 8;28(12):18431-18439. doi: 10.1364/OE.391242.
A novel fiber optic extrinsic Fabry-Perot interferometric (EFPI) ultrasonic sensor with two resonant frequencies for detecting the partial discharges (PDs) in switchgear is demonstrated. The key sensing element consists of two 5-µm-thickness and beam-supported silicon diaphragms, whose natural frequencies are designed differently to enable the sensor to achieve the resonant responses at two different frequencies, thus obtaining a broadened frequency response. The sensing element is fabricated by employing the microelectromechanical systems (MEMS) technology on a silicon-on-insulator (SOI) wafer. The experimental results show that the sensor possesses two resonant frequencies of 31 kHz and 63 kHz, and obviously, shows a highly sensitive frequency response over a broader range compared with the approach composed of a single sensing diaphragm with only one resonant frequency. The noise-limited minimum detectable ultrasonic pressure (MDUP) reaches 251 µPa/Hz@ 31 kHz and 316 µPa/Hz@ 63 kHz, respectively.
展示了一种用于检测开关设备局部放电（PD）的具有两个谐振频率的新型光纤外腔法布里-珀罗干涉（EFPI）超声传感器。关键传感元件由两个厚度为5μm且由梁支撑的硅膜片组成，其固有频率设计不同，以使传感器能够在两个不同频率下实现谐振响应，从而获得更宽的频率响应。传感元件是通过在绝缘体上硅（SOI）晶圆上采用微机电系统（MEMS）技术制造的。实验结果表明，该传感器具有31kHz和63kHz两个谐振频率，并且显然，与由仅具有一个谐振频率的单个传感膜片组成的方法相比，在更宽的范围内显示出高度灵敏的频率响应。噪声限制下的最小可检测超声压力（MDUP）分别在31kHz时达到251μPa/Hz，在63kHz时达到316μPa/Hz。
