ANALYSIS OF CAPACITANCE AND LINEARITY OF GAUGE CHARACTERISTIC OF COPLANAR MICRO-DISPLACEMENT SENSOR

Galina M. Gorbova, Mikhail M. Gorbov, Gerard C.M. Meijer

Abstract

Capacitive sensors can be applied for measuring different kind of non-electrical quantities, such as geometrical dimensions of subjects, thickness of films, displacement and vibration of grounded surfaces, position of the object and others.<BR /> Existing three-electrode micro-displacement sensors, made in the shape of flat capacitor geometry, do have high values of sensitivity, but they also have notable non-linear behaviour over their whole gauge characteristics.<BR /> A three-electrode coplanar sensor, subject of this paper, can be designed by calculation in such a way, that its gauge characteristic does have relatively large section with relative error of the non-linearity of its gauge characteristic equals 0,051% within certain ratio of sensor dimensions.<BR /> The method of direct field-strength determination, in combination with the method of conformal mapping, is used for a precise analytical calculation of the sensor capacitance. Analysis of the capacitance and special cases of sensor design has been discussed.

Keywords

capacitance calculation, micro-displacement

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PWC-2003-TC15-011.pdf

DOI

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IMEKO TC

TC15 - Experimental Mechanics

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