Computation of equivalent circuit parameters of QCM and evaluation of the measurement uncertainties

Abstract

This paper presents an approach of computing the parameters of quartz crystal microbalance (QCM) equivalent circuit model using the least squares algorithm in MATLAB. Modification of the measured data's order in the least squares algorithm was implemented so that the precision was improved. Compared with nonlinear least squares algorithm, the computation method in this paper was faster and simpler with little lower accuracy. Moreover, Monte Carlo Method was utilized to evaluate the measurement uncertainties. An experiment on the temperature response of QCM's equivalent circuit parameters was performed to show that the proposed approach was accurate and fast. The measurement errors are less than 0.6%. © the authors.