Wu Lingqi, Tian Zheng, Ren Dahai, You Zheng
State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China.
Micromachines (Basel). 2018 Dec 17;9(12):666. doi: 10.3390/mi9120666.
A microelectromechanical system (MEMS) torsional resonant magnetometer based on Lorentz force was investigated, consisting of torsional structures, torsional beams, metal plates, a coil, and a glass substrate. The Lorentz force, introduced by the interaction between the current in the MEMS coil and an external horizontal magnetic field, leads to displacement of the torsional structure. The strength of the magnetic field is proportional to this displacement, and can be detected with two sensing capacitors fabricated on the torsion structure and the substrate. To improve sensor sensitivity, a folded torsional beam and a double-layer excitation coil were introduced. The fabrication processes included lift-off, anodic bonding, chemical mechanical planarization, silicon nitride (SiNx) deposition, plasma-enhanced chemical vapor deposition, and inductively coupled plasma release. The prototype of the magnetometer was finished and packaged. The sensor performance, including its sensitivity and repeatability, was tested in a low-pressure environment. Additionally, the influences of structural parameters were analyzed, including the resistance of the excitation coil, the initial value of the capacitors, the elastic coefficient of the torsional beam, and the number of layers in the excitation coil. The test results demonstrated that this sensor could meet the requirements for attitude determination systems in low earth orbit satellites.
研究了一种基于洛伦兹力的微机电系统（MEMS）扭转共振磁力计，它由扭转结构、扭梁、金属板、线圈和玻璃衬底组成。MEMS线圈中的电流与外部水平磁场相互作用产生的洛伦兹力，导致扭转结构发生位移。磁场强度与该位移成正比，可通过在扭转结构和衬底上制作的两个传感电容进行检测。为提高传感器灵敏度，引入了折叠扭梁和双层激励线圈。制造工艺包括剥离、阳极键合、化学机械平面化、氮化硅（SiNx）沉积、等离子体增强化学气相沉积和电感耦合等离子体释放。完成了磁力计原型并进行了封装。在低压环境下测试了传感器性能，包括灵敏度和重复性。此外，分析了结构参数的影响，包括激励线圈的电阻、电容的初始值、扭梁的弹性系数以及激励线圈的层数。测试结果表明，该传感器能够满足低地球轨道卫星姿态确定系统的要求。
