Design, analysis and simulation of capacitive tilt microsensors

In this paper, capacitive tilt micro sensors based on the MEMS technology are designed, analyzed and simulated. These micro sensors are cylindrical and interdigital capacitors (IDC) of the structure from copper, are located on one of their bases. Electrodes of the IDCs are located on the same plate and connected to the ground or terminal voltage. Half of the cylinder is filled with the silicone oil while there is air in the other half. By rotating the cylinder around the x-axis, as the oil level inside the cylinder remains horizontal due to the gravity, position of the electrode’s surfaces which are located inside the oil changes, so tilt around this axis is measured. Two structures are proposed to measure tilt around the x-axis. In this paper, using detailed analysis, the effect of the angular changes on the structural capacitors and outputs is investigated. Moreover, the proposed structures have been simulated by COMSOL Multiphysics software. The results of simulation and analysis are in good agreement. The measuring range of these structures is -90 ° to 90 ° or 0 ° to 180 °  with the sensitivity of 44 fF/deg and 88 fF/deg for one and two-capacitor structure, respectively.