An Evaluation Method of Brownian Noise in Highly Sensitive Capacitive Sensors

Abstract

This paper reports a novel method of evaluating the actual Bn (Brownian Noise) in capacitive sensors for high sensitivity. By analyzing the frequency response of the electrical impedance, the proposed method provides an advantage of evaluating the Bn associated with the mechanical characteristics of capacitive sensors even when the sensors are packaged. We employed the method to measure the quality factors of the MEMS capacitive sensors, and evaluated the value of the Bn and the damping coefficients. The experimental results show a good agreement with the conventionally-known physical parameters.