Mass measurement method based on resonance frequency of the capacitive thin membrane sensor

摘要

This paper introduces a mass measurement method and a system for capacitive membrane sensor, which uses the principle of membrane displacement at a resonance frequency which maximizes output voltage due to its strong vibration. The implemented system consists of dedicated hardware, firmware, and PC. The resonance frequencies of the Si3N4 membrane film are 59.2 kHz and 58.2 kHz measured using laser vibrometer and the proposed method, respectively. The resonance frequency of which quartz has a resonance frequency of 32.768 kHz is 32.775 kHz by our method. The suggested method has 600 times more sensitive in measuring the resonance frequency of a capacitive membrane than the conventional static capacitance measurement method.