Study on linearity of a micromachined convective accelerometer

Abstract

The linearity of a micromachined convective accelerometer without solid proof mass is numerically and experimentally studied in this paper. The accelerometer consists of a micro heater and two temperature sensors which measure the gas temperature difference between two symmetrical positions on both sides of the micro heater. The temperature difference is caused by free convection due to acceleration. The simulation results show that the output of the convective accelerometer is linear with the Grashof number only when the Grashof number is smaller than 10 3 and larger than 10 −2. It will be favorable for achieving good linearity and high sensitivity synchronously as the non-dimensional sensor position, defined by the ratio of the distance from the heater to the half cavity length, is around 0.3. Design considerations are given based on the simulation analysis, a micromachined convective accelerometer is manufactured by bulk-silicon fabrication, the test results demonstrate that it has good linearity and high sensitivity.