一种高品质因子模态局域化MEMS电场传感器

Objective High-performance Micro-Electro-Mechanical Systems (MEMS) Electric Field Sensors (EFS) are essential for measuring atmospheric electric fields and non-contact voltage. The mode localization effect can significantly improve resolution and is a recent focus in EFS research. However, in weakly coupled resonant systems, mode aliasing occurs when the quality factor is low, hindering the extraction of valid amplitude information. This study proposes a novel resonant MEMS EFS based on mode localization. The sensor employs a Double-Ended Tuning Fork (DETF) structure and a T-shaped tether to minimize energy loss, achieving a high-quality factor and resolution while effectively mitigating mode aliasing. This study presents theoretical analysis and numerical simulations. A prototype is fabricated and tested at a pressure of 10⁻³ Pa . Experimental results demonstrate that within an electric field range of 0～90 kV/m, the EFS exhibits a resolution of 32(V/m)/^√Hz, and a quality factor of 42,423. Methods The sensor comprises two coupled resonators based on a tuning fork and T-shaped tether structure. It utilizes the principle of mode localization and an amplitude ratio output metric to enhance electric field sensing performance and prevent mode aliasing. The primary measurement principle is based on the transmission of induced charge from the electric field sensing electrode to the perturbed electrode of Resonator 1 through an electrical connection. This perturbed electrode generates a negative electrostatic perturbation, inducing mode localization in the coupled resonators. The resulting change in the amplitude ratio enables electric field detection. Furthermore, the tuning fork and T-shaped tether structure are designed to minimize clamping and anchor losses, thereby achieving a high-quality factor and effectively mitigating mode aliasing. Results and Discussions This study presents a mode-localized MEMS EFS that achieves a high-quality factor of 42,423 and a high resolution of 32 (V/m)/^√Hz, effectively preventing mode aliasing. Experiments are conducted in a vacuum chamber at a pressure of 10⁻³ Pa . The vacuum environment leads to heat accumulation from the amplifiers on the circuit board, increasing the board’s temperature and causing temperature drift in the sensor. Temperature drift is identified as the primary source of error in sensor testing. Future work will focus on testing the sensor chip with vacuum packaging to mitigate temperature drift caused by the vacuum chamber. Further optimization of the chip and circuit structures is conducted to minimize the effects of feedthrough and parasitic capacitance. Additionally, a differential structure will be designed to enhance common-mode rejection. Conclusions This study addresses mode aliasing in weakly coupled structures by proposing a mode-localized EFS based on a DETF and a T-shaped tether design. The DETF reduces clamping losses, while the T-shaped tether minimizes anchor losses. These structural optimizations reduce energy dissipation, enhance the quality factor, and effectively mitigate mode aliasing. The structural design, working principle, and sensitivity characteristics of the sensor are analyzed through numerical simulations, demonstrating that a lower quality factor under the same coupling strength can induce mode aliasing. The sensor fabrication process is introduced, and a prototype is developed. A testing system is established to evaluate the sensor’s performance in both open-loop and closed-loop configurations. Experimental results indicate that under a pressure of 10⁻³ Pa and within an electric field range of 0～90 kV/m, the sensor achieves a quality factor of 42,423, a resolution of 32 (V/m)/^√Hz, and a sensitivity of 0.0336 /(kV/m). The sensor demonstrates a high-quality factor and excellent electric field resolution while effectively mitigating mode aliasing in mode-localized sensors. This work provides valuable insights for EFS research and the structural design of mode-localized sensors.