Numerical Capacitance Calculation for Mems Pressure Sensor by Method of Moments
P. Li and R.J. Weber
IOWA STATE UNIVERSITY, US
MEMS, pressure sensor, method of moment, diaphragm, capacitance
MEMS-based capacitive pressure sensors have been widely used in many engineering applications. The design of a MEMS capacitance pressure sensor presents a number of challenges, one of which is the calculation of sensor capacitance and the rate of capacitance change with respect to that of pressure applied. Currently, several approaches have been presented to obtain the sensor capacitance; they include analytical solution on the first order, using finite element analysis (FEA) software packages, and using reference calibration capacitance coupled with active signal processing. This paper presents an algorithm based on Method of Moment, which can be implemented in any programming language. This algorithm offers better accuracy than 1st order analytical solutions by considering capacitance fringing effects and other non-idealities, and it does not require expensive Finite Element Analysis software. It also eliminates the need for a powered circuit required in solutions incorporating active signal processing. The results obtained via this algorithm will be compared to that from a commercial Finite Element Analysis software and measurement results from actual, fabricated sensor devices.
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Nanotech 2006 Conference Program Abstract