Effects of Mechanical Geometries on Resonance Sensitivity of MEMS Out-of-Plane Accelerometer

Mechanical geometry such as flexure's beam width, beam length, shin length and movable plate's size variations have effects on the resonance frequency because it's change the values of spring's constant and mass of the structure. This paper presents the effects of these mechanical geometries on resonance of MEMS out-of-plane accelerometer using Architect module in CoventorWare. Resonance frequency of the accelerometer is important because it determines the working frequency bandwidth of the accelerometers. Sensitivity analysis is carried out to determine which geometry most affects the device performance and needs to be controlled. An out-of-plane accelerometer with a fixed and a movable plate suspended by four flexures is used. Sensitivity by analysis shows resonant frequency decreases by 1.422% with 1% increase in beam length while the lowest changes is -0.061% of resonant frequency with 1% increase in shin length.