基于高阶多模态可调机理的MEMS静电谐振器及谐振式传感器研究

MEMS electrostatic resonators and resonant sensors have better performance when they work at higher modes, but higher modes are difficult to be excited, detected and tuned. In this project, resonators with higher-multi modes and adjustable mechanism are proposed, Based on the mechanism, resonant sensors (accelerometer and electrometer) with adjustable sensitivity, high resolution and large dynamic range are studied. The project includes three scopes: (1) investigating electrodes configuration and multi-node excitation and detection, building models for parametric excited vibration, analyzing coupling effect between multi modes, proposing selectable excitation and switching control strategy; (2) investigating nonlinear dynamic characteristics of each mode of the resonator, and seeking method of eliminating nonlinearity in amplitude-frequency for high modes; (3) designing sensitivity-adjustable resonant accelerometers and electrometers based on the higher-multi modes resonator, studying sensing mechanism to input force for the resonant element, revealing influence rule of mode order on sensitivity, resolution and range of the sensors, putting forward a control strategy of mode switching and sensitivity gradient, establishing optimal strategy of multi thresholds for acceleration and charge detection. The project achievements provide theoretical guidance and technical support for the realization of broadband modulation resonators and resonant sensors with high sensitivity, high resolution and large dynamic range.

MEMS静电谐振器及谐振式传感器工作在高阶模态时有更好的性能，但高阶模态难以被激励、检测和调制。本项目提出谐振器的高阶多模态可调机理，并基于该机理研究高分辨率、大量程的灵敏度可调谐振式传感器（加速度计和静电计）。研究内容包括:(1)研究谐振器的电极配置方法及多点激振和检测机制，建立高阶模态多点参激振动的力学模型，分析多模态耦合效应，提出多模态的可选择性激振和切换控制策略；(2)研究谐振器各阶模态的非线性动力学特征，探索高阶模态振幅-频率非线性的消除方法；(3)基于高阶多模态谐振元件设计灵敏度可调谐振式加速度计和静电计，研究谐振元件对外部输入力的敏感机制，揭示模态阶数对传感器灵敏度、分辨率、量程的影响规律，提出模态切换与灵敏度梯度的控制策略，建立多阈值加速度、电荷检测的最优策略。本项目成果为实现宽频调制谐振器，以及高分辨率、大量程的灵敏度可调谐振式传感器供理论指导和技术支持。

针对传统谐振式传感器灵敏度小、非线性严重的问题，本报告研究微机械谐振器的关键非线性动力学问题，提出基于静电谐振器的新型电荷传感器和加速度计，探索高灵敏度低非线性谐振式传感器的优化方法。建立谐振结构在力场-电场-温度场耦合作用下的力学模型，研究高阶多模态谐振器的非线性行为。采用该谐振器作为敏感元件提高谐振式传感器灵敏度，实现灵敏度可调，并利用微杠杆放大惯性力或静电力提高灵敏度。基于高阶多模态灵敏度可调与放大机理，开发了实现高灵敏度、高精度谐振式加速度计和电荷传感器样机，为高精度MEMS谐振式传感器的实现提供理论指导和技术支持。研究内容包括：（1）MEMS静电谐振器的非线性行为控制研究；（2）MEMS静电谐振器的馈通寄生效应研究；（3）MEMS谐振式静电计及灵敏度可调机理；（4）单电子分辨率的高阶模态MEMS谐振式静电计研究；（5）高阶模态灵敏度提升与可调的MEMS谐振式加速度计设计。实现了3.61ppb/e的线性电荷灵敏度，同时实现了室温下0.17e/√Hz的超高电荷分辨率以及67个电子积累的实时监测，电荷检测的动态范围149dB。将高阶模态敏感机理应用于湿度和气体传感器，设计叉指电极优化激发压电悬臂梁的高频模式，相对灵敏度大幅度提高。研究成果包括：发表SCI论文48篇，包括中科院一区论文11篇，ESI高被引论文1篇。发表EI国际会议论文28篇，授权发明专利6项，出版著作（英文）章节1章。培养6位博士生和8位硕士生，指导的1位博士生基于该项目撰写的博士论文获上银优秀机械博士论文佳作奖。