Electrostatic+driving

Electrostatic+driving - SEN2MET Electrostatic driving...

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SEN2MET Electrostatic driving
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Electrostatic driving •Theory governed by basic electrostatics •For microstructures electrostatic, elastic mechanical and damping forces are comparable so all have to be considered together •Joint action of electrostatic and elastic forces can cause nonlinearity and instability problems •Dimension of structure and gaps are comparable giving fringing effects
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Normal and tangential forces The normal force is always attractive between the plates. It is non-linear both in distance and voltage. Source of instability and noise. F T is independent of displacement Usually F N is much larger than F T due to smaller gap than overlap. Both forces may be present in a microsystem resonator so special care is needed to control this. E.g. a comb resonator
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Fringing capacitance Due to fringing effects the capacitance is larger than the parallel plate capacitance. The side edges and the back side may also contribute significantly to the capacitance z 2a   a z a z C a z h l z C r 2 ln 2 2 1 arccos 0 0 
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This note was uploaded on 05/30/2011 for the course SEN 2MET taught by Professor Ulrikhanke during the Spring '11 term at VCU.

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Electrostatic+driving - SEN2MET Electrostatic driving...

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