论文信息 - Improvement of the linearity of a capacitive pressure sensor using an interdigitated electrode structure

Improvement of the linearity of a capacitive pressure sensor using an interdigitated electrode structure

Abstract A simulation program (CAPS) calculating the deflection and capacitance change as a function of applied pressure for vm'ious electrode structures and operating conditions has been deveIoped. With its aid, a new method for improving the linearity of a capacitive pressure sensor is proposed. Since the output capacitance of the capacitive pressure sensor is inversely proportional to the gap between the parallel electrodes, the capacitance exhibits non-linearity. The non-linearity is reduced by eliminating the area of large deflection (centre of the diaphragm) from the output capacitance. A prototype device has been designed by using CAPS to reduce the non-linearity and is fabricated using silicon bulk- micromachining technology. The sensitivity degradation and linearity improvement resulting from the use of such an interdigitated electrode structure are 65% and 620%, respectively. By using the interdigitated electrode structure and the simulation program developed in this research, we can optimize the performance of capacitive pressure sensors.

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