A simple capacitance calculation formula for MEMS capacitive type sensors with square membranes

Author

Rahman, Mosaddequr ; Abbas, Syed ; Chowdhury, Sazzadur

Author_Institution

Dept. of Electr. & Comput. Eng., Univ. of Windsor, Windsor, ON, Canada

fYear

2009

fDate

June 28 2009-July 1 2009

Firstpage

1

Lastpage

4

Abstract

A simple highly accurate mathematical method has been developed to calculate capacitance change for MEMS capacitive type sensors with square membranes. The method improves the accuracy of existing methods as it takes account of the membrane deflection due to the electrostatic pressure in addition to the external mechanical pressure, considers the fringing field effects, and is also applicable to large deflection cases. The model has been verified by 3-D electromechanical finite element analysis for a wide range of loading conditions. The model predicted values are found to be in excellent agreement with the FEA results with a maximum deviation of 5.08% for the membrane center deflection and 5.76% for capacitance values for different external pressure loading and electrostatic bias voltage.

Keywords

capacitive sensors; electrostatic devices; finite element analysis; membranes; microsensors; 3D electromechanical finite element analysis; FEA; MEMS capacitive-type sensors; capacitance calculation formula; electrostatic bias voltage; electrostatic pressure; external mechanical pressure; external pressure loading; fringing field effects; membrane center deflection; square membranes; Acoustic sensors; Biomembranes; Capacitance; Capacitive sensors; Electrostatics; Mechanical sensors; Micromechanical devices; Residual stresses; Temperature sensors; Voltage;

fLanguage

English

Publisher

ieee

Conference_Titel

Circuits and Systems and TAISA Conference, 2009. NEWCAS-TAISA '09. Joint IEEE North-East Workshop on

Conference_Location

Toulouse

Print_ISBN

978-1-4244-4573-8

Electronic_ISBN

978-1-4244-4574-5

Type

conf

DOI

10.1109/NEWCAS.2009.5290456

Filename

5290456