scholarly journals Numerical and compact modelling of squeeze-film damping in RF MEMS resonators

2008 ◽  
Author(s):  
T. Veijola ◽  
A. Lehtovuori
Keyword(s):  
Rf Mems ◽  
Squeeze Film ◽  
Squeeze Film Damping ◽  
Mems Resonators

A Fully Coupled FEM Model of Electromechanically Actuated MEMS With Squeeze Film Damping

2009 ◽  
Author(s):  
Stephan D. A. Hannot ◽  
Daniel J. Rixen
Keyword(s):  
Rf Mems ◽  
Squeeze Film ◽  
Fem Model ◽  
Mems Switch ◽  
Squeeze Film Damping ◽  
Air Damping ◽  
Mems Resonators ◽  
Fluid Damping ◽  
Frequency Behavior ◽  
Damping Model

A specific type of Microsystems or MEMS is the so called RF-MEMS switch. In contrast to MEMS resonators switches generally do not operate in a vacuum. Therefore at the small scales of MEMS fluid (or air) damping is the most dominant damping form. This means that if one is interested in transient or frequency behavior a proper damping model is required. This paper presents a way of using the non-linear Reynolds equation to model the squeeze film damping that is often the type of fluid damping present in these switches. The formulation is provided ready for FEM implementation. Also the tangent matrices required for linearized eigen frequencies are derived. The equations are tested on a model of simple micro switch. The results show that with this model it is possible to predict the damped motion as well as the frequency behavior. The frequency results also show that damping shifts the zero frequency point away from the pull-in point. With a simple mechanical contact model it is also possible to model the closing and opening transient of a microsystem.

Reduction of squeeze-film damping in a wafer-level encapsulated RF MEMS DC shunt switch

2011 ◽  
Vol 171 (2) ◽  
pp. 118-125
Author(s):  
Feixiang Ke ◽  
Jianmin Miao ◽  
Chee Wee Tan
Keyword(s):  
Rf Mems ◽  
Squeeze Film ◽  
Wafer Level ◽  
Squeeze Film Damping

Dynamic Response of a Piezoelectric Flextensional Microactuator

2005 ◽  
Author(s):  
Jongpil Cheong ◽  
Srinivas Tadigadapa ◽  
Christopher D. Rahn
Keyword(s):  
Dynamic Response ◽  
Frequency Response ◽  
Natural Frequencies ◽  
Rf Mems ◽  
Squeeze Film ◽  
Beam Shape ◽  
Initial Beam ◽  
Carbon Tape ◽  
Squeeze Film Damping ◽  
Soft Carbon

Microactuators capable of providing high resolution displacement and controlled force have many applications in RF MEMS, microfluidics, and motion control. This paper theoretically and experimentally investigates the dynamic response of a piezoelectric flextensional microactuator consisting of a clamped beam that buckles in response to contraction of a bonded PZT support. The DRIE and solder bonding fabrication process produces beams with initial curvature that affects their dynamic response. Unlike previous research where sinusoidal initial beam shapes are analyzed, polynomial initial beam shape enables more accurate prediction of beam natural frequencies and frequency response when compared with experimental results. The inclusion of squeeze film damping between the beam and PZT support enables the model to predict frequency response. Experiments show that mounting the PZT with soft carbon tape limits PZT vibration.

Nonlinear Vibration of Electrostatically Actuated MEMS Resonators Under Parametric and External Excitations

2007 ◽  
Author(s):  
Wen-Ming Zhang ◽  
Guang Meng ◽  
Di Chen
Keyword(s):  
Dynamic Characteristics ◽  
Nonlinear Dynamic ◽  
Squeeze Film ◽  
Electrostatically Actuated ◽  
Squeeze Film Damping ◽  
Mems Resonators ◽  
Nonlinear Dynamic Characteristics ◽  
Dynamical Parameters ◽  
Parametric And External Excitations ◽  
Significant Attention

Electrostatically actuated resonant MEMS (Micro-electromechanical Systems) have gotten significant attention due to their geometric simplicity and broad applicability. In this paper, analyses and simulations for the dynamics of electrostatically actuated MEM structures under parametric and external excitations are presented. The presented model and methodology enable simulation of the dynamics of the electrostatic MEM structure undergoing small motions. The numerical results showing the effects of varying the applied voltages and the squeeze film damping on the resonant frequencies and nonlinear dynamic characteristics are given in detail. Resonant frequency and peak amplitude are examined for variation of the dynamical parameters involved. It is demonstrated that the system goes through a complex nonlinear oscillation as the system parameters change. This investigation provides an understanding of the nonlinear dynamic characteristics of electrostatically actuated resonant MEMS.

scholarly journals Dynamics of Nonlinear Coupled Electrostatic Micromechanical Resonators under Two-Frequency Parametric and External Excitations

2010 ◽  
Vol 17 (6) ◽  
pp. 759-770 ◽  
Author(s):  
Wen-Ming Zhang ◽  
Guang Meng ◽  
Ke-Xiang Wei
Keyword(s):  
Dynamic System ◽  
Quality Factor ◽  
Electrostatic Force ◽  
Squeeze Film ◽  
Largest Lyapunov Exponent ◽  
Nonlinear Phenomena ◽  
Electrostatically Actuated ◽  
Squeeze Film Damping ◽  
Mems Resonators ◽  
Parametric And External Excitations

In this paper, nonlinear dynamics and chaos of electrostatically actuated MEMS resonators under two-frequency parametric and external excitations are investigated analytically and numerically. A nonlinear mass-spring-damping model is used to accounting for squeeze film damping and the parallel plate electrostatic force. The micro-structure is excited by a dc bias electrostatic force and a harmonic force with a frequency tuned closely to their fundamental natural frequencies (combination oscillation). The quality factor is calculated for the microcantilever beam of the resonator considering squeeze film damping. The effect of nonlinear squeeze film damping on the frequency response, quality factor, resonant frequency and nonlinear dynamic characteristics of the dynamic system are provided with numerical simulations using the bifurcation diagram, Poicare maps, largest Lyapunov exponent and phase portrait. The results show that the dynamic system goes through a complex nonlinear vibration as the system parameters change. It is indicated that the effect of nonlinear squeeze film damping should be considered due to its decreasing the quality factor and changing the nonlinear phenomena of the MEMS resonators.

A Study of Non-Uniform SPST RF-MEMS Switch under the Effect of Squeeze Film Damping

2013 ◽  
Vol 339 ◽  
pp. 157-162
Author(s):  
Omar A. Awad ◽  
Ameen El-Sinawi ◽  
Maher Bakri-Kassem ◽  
Taha Landolsi
Keyword(s):  
Rf Mems ◽  
Mode Shapes ◽  
Squeeze Film ◽  
Rf Mems Switch ◽  
Mems Switch ◽  
Squeeze Film Damping ◽  
Squeeze Film Effect ◽  
Proposed Model ◽  
Modal Model ◽  
Hankel Norm

This work presents a practical technique that can be used to construct the dynamic model of any RF MEMS switch regardless of its shape. The presented technique also allows for inclusion of squeeze film effect in the model without resorting to complex mathematical development of the latter. The technique utilizes Finite element methods to determine mode shapes and natural frequencies of the switch. A modal-model is then constructed from the FEA results. The model can be reduced using by retaining modes with highest Hankel norm modes to reduce calculations effort associated with large models. Simulation results have shown that the proposed model has merit and agrees with published experimental data.

Simulation of the Squeeze Film Damping in a RF MEMS Switch

2013 ◽  
Vol 427-429 ◽  
pp. 116-119
Author(s):  
Xiang Guang Li ◽  
Qin Wen Huang ◽  
Yun Hui Wang
Keyword(s):  
Surface Pressure ◽  
Reynolds Equation ◽  
Dynamic Models ◽  
Mechanical Response ◽  
Rf Mems ◽  
Squeeze Film ◽  
Damping Force ◽  
Rf Mems Switch ◽  
Mems Switch ◽  
Squeeze Film Damping

Two different dynamic models have been presented to investigate the transient mechanical response of a RF MEMS switch under the effects of squeeze-film damping based on a modified Reynolds equation. Both the perforated and non-perforated structures are built for comparison. The models include realistic dimensions. The surface pressure, the damping force, and the tip displacement are simulated in three different ambient pressures, such as 500Pa, 5kPa, and 0.05MPa. The result shows that the increased damping leads to a substantial decrease in oscillation with increasing pressure for the non-perforated structure. Compared with the perforated pad, there is a much larger damping force acts on the non-perforated surface, and an obvious decrease in damping force with increasing pressure.

scholarly journals INVESTIGATION ON EFFECT OF SURFACE ROUGHNESS PATTERN TO DYNAMIC PERFORMANCE OF MEMS RESONATORS IN VARIOUS TYPES OF GASES AND GAS RAREFACTION

2021 ◽  
Vol 59 (5) ◽  
Author(s):  
Nguyen Chi Cuong ◽  
Lam Minh Thinh ◽  
Phan Minh Truong ◽  
Trinh Xuan Thang ◽  
Ngo Vo Ke Thanh ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Effective Viscosity ◽  
Dynamic Performance ◽  
Squeeze Film ◽  
Molecular Gas ◽  
Q Factor ◽  
Squeeze Film Damping ◽  
Mems Resonators ◽  
Quality Factor Q ◽  
Effect Of Surface

The average modified molecular gas lubrication (MMGL) equation, which is modified with pressure flow factors and effective viscosity, is utilized to analyze the squeeze film damping (SFD) on micro-beam resonators considering effect of surface roughness pattern in various types of gases and gas rarefaction. Then, effect of surface roughness pattern (film thickness ratio and Peklenik number) is discussed on the quality factor (Q-factor) of micro-beam resonators in various types of gases and gas rarefaction. Thus, effect of surface roughness pattern is significantly reduced as effective viscosity of gas decreases in higher mode of resonator and higher gas rarefaction.

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