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Dias, R.A. (author), Cretu, E. (author), Wolffenbuttel, R.F. (author), Rocha, L.A. (author)
The pull-in time of electrostatically actuated parallel-plate microstructures enables the realization of a high-sensitivity accelerometer that uses time measurement as the transduction mechanism. The key feature is the existence of a metastable region that dominates pull-in behavior, thus making pull-in time very sensitive to external...
journal article 2012
document
Dias, R.A. (author), Macedo, P.J. (author), Silva, H.D. (author), Wolffenbuttel, R.F. (author), Cretu, E. (author), Rocha, L.A. (author)
A high-resolution, high dynamic range capacitive accelerometer based on pull-in time measurement is described in this paper. The high sensitivity of pull-in time can be used to implement high performance accelerometers, but non-linearity and low dynamic range compromise device performance. A closed-loop approach using an electrostatic actuation...
journal article 2012
document
Rajaraman, V. (author), Sabageh, I. (author), French, P. (author), Pansraud, G. (author), Cretu, E. (author)
This work reports the design, modelling, fabrication and preliminary functionality testing of a dual-mass MEMS vibratory gyroscope for application in medical instrumentation, among others. The two-framed gyro has drive and sense mode resonance frequencies of 2500Hz and 2830Hz, with its bandwidth tunable between 40-330Hz. Adopted design and...
journal article 2011
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Dias, R.A. (author), Wolffenbuttel, R.F. (author), Cretu, E. (author), Rocha, L.A. (author)
The experimental evaluation of damping-improved parallel-plate geometries is reported in this paper. An improved damper geometry with air channels was developed to address contradictory design constraints: large sensing parallel-plate area is desirable for a significant readout capacitance as well as reduced damping coefficient. Damping...
journal article 2011
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Rocha, L.A. (author), Dias, R.A. (author), Cretu, E. (author), Mol, L. (author), Wolffenbuttel, R.F. (author)
This paper describes an electro-mechanical auto-calibration technique for use in capacitive MEMS accelerometers. Auto-calibration is achieved using the combined information derived from an initial measurement of the resonance frequency and the measurement of the pull-in voltages during device operation, with an estimation of process-induced...
journal article 2011
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Mol, L. (author), Rocha, L.A. (author), Cretu, E. (author), Wolffenbuttel, R.F. (author)
Squeeze-film damping is highly inadequate in low-pressure systems or in systems where air pressure and/or gap dimensions are poorly defined. Input shaping has been used to circumvent the oscillations typically associated with under-damped mass-spring-damper systems and drastically decrease the settling time. The proposed method does not rely on...
journal article 2009
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Mol, L. (author), Rocha, L.A. (author), Cretu, E. (author), Wolffenbuttel, R.F. (author)
This paper provides experimental validation of the predictions by two recent models for squeezed film damping in the free molecule regime. Measurements were carried out using a parallel-plate microstructure with a 2.29 ?m gap operated at pressures from 105 to 101 Pa (corresponding to Knudsen numbers from 0.03 to 300). Experiments are in good...
journal article 2009
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Rocha, L.A. (author), Mol, L. (author), Cretu, E. (author), Wolffenbuttel, R.F. (author), Machado da Silva, J. (author)
A test technique for capacitive MEMS accelerometers and electrostatic microactuators, based on the measurement of pull-in voltages and resonance frequency, is described. Using this combination of measurements, one can estimate process-induced variations in the device layout dimensions as well as deviations from nominal value in material...
journal article 2008
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Mol, L. (author), Rocha, L.A. (author), Cretu, E. (author), Wolffenbuttel, R.F. (author)
journal article 2008
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Rocha, L.A. (author), Cretu, E. (author), Wolffenbuttel, R.F. (author)
journal article 2006
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De Graaf, G. (author), Mol, L. (author), Rocha, L.A. (author), Cretu, E. (author), Wolffenbuttel, R.F. (author)
journal article 2005
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Rocha, L.A. (author), Cretu, E. (author), Wolffenbuttel, R.F. (author)
journal article 2005
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Rocha, L.A. (author), Cretu, E. (author), Wolffenbuttel, R.F. (author)
journal article 2005
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Rocha, L.A. (author), Cretu, E. (author), Wolffenbuttel, R.F. (author)
journal article 2004
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Cretu, E. (author)
doctoral thesis 2003
document
Rocha, L.A. (author), Cretu, E. (author), Wolffenbuttel, R.F. (author)
journal article 2003
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Cretu, E. (author), Rocha, L.A. (author), Wolffenbuttel, R.F. (author)
journal article 2001
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