A Low-g MEMS Accelerometer with High Sensitivity, Low Nonlinearity and Large Dynamic Range Based on Mode-Localization of 3-DoF Weakly Coupled Resonators

This paper presents a new design of microelectromechanical systems (MEMS) based low-g accelerometer utilizing mode-localization effect in the three degree-of-freedom (3-DoF) weakly coupled MEMS resonators. Two sets of the 3-DoF mechanically coupled resonators are used on either side of the single proof mass and difference in the amplitude ratio of two resonator sets is considered as an output metric for the input acceleration measurement. The proof mass is electrostatically coupled to the perturbation resonators and for the sensitivity and input dynamic range tuning of MEMS accelerometer, electrostatic electrodes are used with each resonator in two sets of 3-DoF coupled resonators. The MEMS accelerometer is designed considering the foundry process constraints of silicon-on-insulator multi-user MEMS processes (SOIMUMPs). The performance of the MEMS accelerometer is analyzed through finite-element-method (FEM) based simulations. The sensitivity of the MEMS accelerometer in terms of amplitude ratio difference is obtained as 10.61/g for an input acceleration range of ±2 g with thermomechanical noise based resolution of 0.22 and nonlinearity less than 0.5%.

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A mode-localized MEMS electrical potential sensor based on three electrically coupled resonators

Journal of Sensors and Sensor Systems ◽

10.5194/jsss-6-1-2017 ◽

2017 ◽

Vol 6 (1) ◽

pp. 1-8 ◽

Cited By ~ 3

Author(s):

Chun Zhao ◽

Graham S. Wood ◽

Suan Hui Pu ◽

Michael Kraft

Keyword(s):

Frequency Shift ◽

Dynamic Range ◽

Electrostatic Force ◽

Electrical Potential ◽

Coupled Resonators ◽

Mode Localization ◽

Resonant Sensors ◽

Current State ◽

Weakly Coupled ◽

Resonator System

Abstract. We report a new class of MEMS resonant potential sensor based on the mode localization effect using a 3-degree-of-freedom (DoF) electrically weakly coupled resonator system. As opposed to previously reported electrically coupled 2DoF mode-localized resonant sensors, it can be shown in theory that the 3DoF structure has an improved sensitivity without sacrificing signal transduction, in addition to a reduced nonideal effect with regard to the vibration amplitudes and the motional currents. Experimentally, it has also been shown that several orders of magnitude higher sensitivity can be achieved compared to frequency shift and 2DoF mode-localized sensor. In the best case, we are able to demonstrate over 4 orders of magnitude improvement in sensitivity compared to frequency shift as an output signal. Compared to current state-of-the art 2DoF mode-localized sensor, the highest sensitivity improvement is over 123 times. An estimation of the noise floor of the sensor is 614 µV / √Hz for potential sensing, or an equivalent 57.6e / √Hz for charge sensing, and a dynamic range of 66.3 dB can be achieved. Furthermore, two different approaches for detection were investigated, perturbing the stiffness in the form of either an axial electrostatic force or a change in electrostatic spring. We were able to demonstrate that the approach of changing electrostatic spring is more sensitive than its counterpart.

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A Novel Dual-Mass Accelerometer Exploiting Mode Localization in Electrostatically Coupled Resonators

10.1115/detc2021-67922 ◽

2021 ◽

Author(s):

Ming Lyu ◽

Jian Zhao ◽

Najib Kacem ◽

Pengbo Liu

Keyword(s):

Coupling Strength ◽

Axial Load ◽

Amplitude Ratio ◽

Coupled System ◽

Inertial Forces ◽

Governing Equations ◽

Coupled Resonators ◽

Critical Amplitude ◽

Mode Localization ◽

Vibration Magnitude

Abstract A novel dual-mass accelerometer is proposed while exploiting the phenomenon of mode localization in two electrostatically coupled resonators with an adjustable coupling strength. The external inertial forces are transmitted differentially to the resonators in term of axial load change through the two levering mechanisms, breaking the balanced state and resulting in a drastic change in the amplitudes of the two resonators. Based on the Euler Bernoulli theory, the governing equations of the coupled system are derived and numerically solved. The sensitivity in term of relative shift of amplitude ratio can be improved by 4 orders of magnitude compared to frequency shift. Finally, the effect of the quality factor on the sensor dynamics has also been investigated, and the results show that it only affects the vibration magnitude of the resonators while operating below the critical amplitude.

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An asymmetric mode-localized mass sensor based on the electrostatic coupling of different structural modes with distributed electrodes

10.21203/rs.3.rs-323305/v1 ◽

2021 ◽

Author(s):

Jiahao Song ◽

Ming Lyu ◽

Najib Kacem ◽

Jian Zhao ◽

Pengbo Liu ◽

...

Keyword(s):

Amplitude Ratio ◽

Harmonic Balance Method ◽

Nonlinear Behavior ◽

Mass Sensor ◽

Mass Detection ◽

Coupled Resonators ◽

Critical Amplitude ◽

Asymmetric Mode ◽

Mode Localization ◽

Electrostatic Coupling

Abstract Mode-localization sensor with amplitude ratio as output metric has shown excellent potential in the field of micro-mass detection. In this paper, an asymmetric mode -localized mass sensor with a pair of electrostatically coupled resonators of different thickness is proposed. Partially distributed electrodes are introduced to ensure the asymmetric mode coupling of second and third order modes while actuating the thinner resonator by the distributed electrode. The analytical dynamic model is established by Euler–Bernoulli theory and solved by harmonic balance method (HBM) combined with asymptotic numerical method (ANM). Detailed investigations on the linear and nonlinear behavior, critical amplitude as well as the sensitivity of the sensor are performed. The sensitivity of the proposed sensor can be enhanced by about 20 times compared to first order mode-localized mass sensors. Furthermore, by exploiting the nonlinearities while driving the device beyond the critical amplitude for the in-phase mode, the sensor performs a great improvement in sensitivity up to 1.78 times. Besides, the influence of the decrease of coupling voltage is studied, which gives a good reference to avoid mode aliasing.

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Characteristic Analysis on Transverse Comb Structure Using PSpice

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.627.202 ◽

2014 ◽

Vol 627 ◽

pp. 202-206

Author(s):

C. Kavitha ◽

M. Ganesh Madhan

Keyword(s):

Transient Analysis ◽

Proof Mass ◽

Characteristic Analysis ◽

Maximum Displacement ◽

Electrical Equivalent Circuit ◽

Mems Accelerometer ◽

Comb Structure ◽

Input Acceleration ◽

Mass Displacement ◽

Ansys Workbench

An analysis of transverse comb structure based MEMS accelerometer is carried out. Its static and dynamic behavior is analyzed by employing a simple electrical equivalent circuit in the acceleration range of 0-30g. The device is simulated for dc, transient and frequency conditions. In the transient analysis, the device is excited with sinusoidal and step input acceleration and the proof mass displacement is evaluated. It is found that, the capacitance and displacement values obtained from our simulation matches well with reports from ANSYS Workbench®. The maximum displacement in the structure is evaluated at different condition and the effect of damping is investigated.

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