Static response of miniature capacitive pressure sensors with square or rectangular silicon diaphragm

Abstract

The static response of capacitive pressure sensors with a thin rectangular or square diaphragm is studied, assuming small deflections. Lagrange's equation is solved from the virtual displacement theorem and an approximated polynomial solution. It is shown that response can be expressed under a normalized form dependent only on the value of the diaphragm dimension ratio. For a given silicon surface, square sensors exhibit the highest sensitivity whereas rectangular sensors have a more linear behaviour. Finally, the proposed formulation equally allows easy and rapid determination of the four geometric parameters defining this type of sensor.