Design, analysis and simulation of a novel linear capacitive tilt micro-sensor

Abstract

A new capacitive structure for tilt sensor based on the MEMS technology is designed, analyzed and simulated. With a detailed analysis, we achieve to a precise relation between capacitance and inclination angle. Taking advantage of cylindrical structure in our design, we reach to a linear relationship between capacitance and tilt angle. In three designs of our capacitive tilt micro-sensor, there are 1, 2 and 4 micro capacitors. These capacitors have a common plate of mercury which is movable. Another plate is fixed. Displacement of mercury according to the deflection tends to the variations of capacitors and subsequently total capacitance of the tilt micro-sensor changes. In each of three designs for this micro-sensor, output capacitance (Cout) is introduced with a special equation for obtaining a linear and continues relationship between Cout and tilt angle. The last proposed micro-sensor structure with 4 micro capacitors, shows linear relationship for Cout over tilt measurement range of ź180° to +180° on one axis besides proper sensitivity.