In this paper, we developed a multi-physics model of an electrostatic MEMS resonator made of an array of mechanically-coupled beams and investigate its potential use for mass detection applications. Experiments were conducted on two- and three-coupled beams under electrostatic actuation to verify the capability of the model to predict the mechanical response of coupled beam arrays. The fabricated device, comprising polysilicon-coupled microbeams, is produced using the Multi-User MEMS Processes, followed by an experimental investigation. Numerical results were found in good agreement with their experimental counterparts. The developed model was used to demonstrate the possible adjustment of the electrostatic actuation to enhance the sensitivity of the dynamic response of the coupled MEMS resonator to mass perturbations. By leveraging the mode localization phenomenon and incorporating a novel differential capacitance sensing mechanism, a notable 84% improvement in sensitivity when switching from two-beam to three-beam system while operating near the second mode in the linear regime. Actuating the MEMS device at higher voltages enabled to achieve higher sensitivity thanks to the activation of nonlinear effects such as bifurcation and softening. We observed the transition from nonlinear to nearly-linear dynamic response of the coupled beams upon the addition of mass and demonstrated how bifurcations that cause a sudden shift to a high-amplitude motion can be utilized in differential capacitance-based mass sensing. Additionally, the suggested detection mechanism allows for overcoming the inherent parasitic capacitance, thereby mitigating low signal-to-noise ratios.

中文翻译：

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基于耦合微束阵列模式定位的差分电容质量传感


在本文中，我们开发了由机械耦合梁阵列组成的静电 MEMS 谐振器的多物理模型，并研究了其在质量检测应用中的潜在用途。在静电驱动下对二耦合梁和三耦合梁进行了实验，以验证模型预测耦合梁阵列机械响应的能力。所制造的器件由多晶硅耦合微束组成，采用多用户 MEMS 工艺生产，随后进行了实验研究。数值结果与实验结果非常吻合。开发的模型用于演示静电驱动的可能调整，以增强耦合 MEMS 谐振器对质量扰动的动态响应的灵敏度。通过利用模式定位现象并结合新颖的差分电容传感机制，当从双光束系统切换到三光束系统时，同时在线性区域中接近第二模式运行时，灵敏度显着提高了 84%。由于激活了分叉和软化等非线性效应，以更高的电压驱动 MEMS 器件能够实现更高的灵敏度。我们观察到添加质量后耦合梁的非线性动态响应到近线性动态响应的转变，并演示了如何在基于差分电容的质量传感中利用导致突然转变为高振幅运动的分叉。此外，所建议的检测机制可以克服固有的寄生电容，从而减轻低信噪比。