Micromachined accelerometer based on differential measurement of air movement

This thesis investigates the possibility of fabricating a new class of accelerometers that work on the principle of air movement measured in a differential fashion. This measurement technique is a patent pending idea of Dr. Albert Leung of the School of Engineering Science, Simon Fraser University.;Device modeling, design, fabrication and characterization are presented. The device configuration is based on the "hot air bubble" concept developed by Dr. Albert Leung. The device consists of a central heater and temperature sensors placed symmetrically on its sides with surrounding air as thermal coupling element.;The less dense "hot air bubble" generated by the heater will be shifted by an applied acceleration, due to buoyancy force. The symmetrically placed sensors will sense the bubble movement in a differential manner, providing an output that is proportional to the applied acceleration. The advantages of this new device over those of existing accelerometers are its simplicity and robustness. These advantages result from the device having no solid moving parts.;Analytical models of the device functional blocks were developed to gain an insight into the device behavior. The analytical model results were used to derive guidelines on device dimensions. Based on analytical solutions, the temperature distribution, heat flow and response time were calculated.;The air temperature distribution is also determined using an ANSYS simulator. Streamlines and isotherms for air flow within the system are presented. The air flow regimes that arise are determined as a function of device geometry and temperature. The numerical results are compared with the analytical model results in order to check the validity of proposed analytical models. (Abstract shortened by UMI.)...