Chen Tao, Shafai Cyrus
Department of Electrical & Computer Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada.
Sensors (Basel). 2024 Jan 11;24(2):439. doi: 10.3390/s24020439.
Micromachined electric field mills have received much interest for the measurement of DC fields; however, conventional designs with lateral moving shutters could have shutter lifting in the presence of strong fields, which affects their performance. This paper presents a MEMS electric field mill utilizing a vertical movement shutter to address this issue. The sensor is designed and fabricated based on a flexible PCB substrate and is released using a laser-cutting process. The movement of the shutter is driven by an electrostatic actuator. When the driving signal is a sine wave, the shutter moves in the same direction during both the positive and negative half-periods. This facilitates the application of a lock-in amplifier to synchronize with the signal at twice the frequency of the driving signal. In experimental testing, when the vertical shutter is driven at a resonance of 840 Hz, the highest sensitivity of the sensor is achieved and is measured to be 5.1 V/kVm. The sensor also demonstrates a good linearity of 1.1% for measuring DC electric fields in the range of 1.25 kV/m to 25 kV/m.
微机械电场传感器在直流电场测量方面备受关注；然而，传统的带有横向移动快门的设计在强电场存在时可能会出现快门抬起的情况，这会影响其性能。本文提出了一种利用垂直移动快门的微机电系统（MEMS）电场传感器来解决这一问题。该传感器基于柔性印刷电路板（PCB）基板进行设计和制造，并通过激光切割工艺进行释放。快门的移动由静电致动器驱动。当驱动信号为正弦波时，快门在正半周期和负半周期都沿相同方向移动。这便于应用锁相放大器与驱动信号频率两倍的信号同步。在实验测试中，当垂直快门以840 Hz的共振频率驱动时，传感器实现了最高灵敏度，测量值为5.1 V/kVm。该传感器在1.25 kV/m至25 kV/m范围内测量直流电场时也表现出1.1%的良好线性度。
