Research On Dynamic Characteristics Of MEMS Resonator With Nonlinear Weakly Coupled Double Curved Beam Structures

The function of traditional MEMS resonator depends on the performance of its elastic element and driving mode.With the single sensing function(micro mass or acceleration)or filtering function,it is difficult to adapt to the complex and changeable vehicle application environment.In this paper,a MEMS resonator with nonlinear weakly coupled double curved beam structure and its nonlinear dynamic characteristics are analyzed.By adjusting different control parameters,the functions of micro mass weighing,threshold switch and filter can be switched,which can be reused in vehicle environment measurement and radar signal processing system.The specific research contents include:(1)The dynamic model of the weakly coupled double curved beam structure driven by electrostatic force is established.The model order is reduced and discretized by Galerkin Method.The static response is solved by means of the Asymptotic Numerical Method(ANM),Runge-Kutta Method(RKM)and Finite Element Method(FEM)respectively,and results are consistent with those in the literature,Thus,the accuracy of the proposed model is verified.(2)The dynamic model of the micro mass sensor based on the mode localization of two weakly coupled double curved beams is established.The equilibrium point is determined by eigenvalue analysis.The dynamic response of the micro mass sensor is analyzed by combining the Asymptotic Numerical Method(ANM)with the Harmonic Balance method(HBM).Using the amplitude ratio to depict the sensitivity,the influence of AC driving voltage on the sensitivity of the sensor is systematically studied.The simulation results show that the sensitivity of the proposed sensor is 524.4 times higher than that of the traditional frequency difference method.(3)A threshold type mass sensor based on nonlinear bifurcation jump is designed.The threshold sensing function is realized by adjusting the weak coupling voltage to be zero.The influence of DC driving voltage,AC driving voltage and excitation frequency on the threshold value is studied by parametric analysis.The results show that the threshold value can reach3～38 μg.It is found that the sensor can still be used as a micro mass weighing sensor after snapping through,and the response amplitude of the sensor is linear with the micro mass.(4)The control method of MEMS two-stage bandpass filter based on the same structure is proposed.The results show that the center frequency is adjustable,the ripple in the band can be reduced to 0.2d B,the percentage of bandpass bandwidth can reach 14.8%,and the rectangular coefficient can reach 1.0.