摘要
In this work, we investigate numerical simulation techniques to generate accurate reduced order models (ROM) in predicting the frequency response of piezoelectric microelectromechanical systems (MEMS) resonators. The ROM converts normalized modal parameters and electromechanical conversion factors (Γn) for different eigenmodes extracted from a finite element method (FEM) model into a multi-branch modified Butterworth-van Dyke (mBVD) circuit. A multi-frequency impedance estimation (MFIE) technique is proposed to enhance the accuracy of the ROM by running harmonic simulation at specific frequency points to accurately extract the motional impedance (Rm) and mechanical quality factors (Qm) for each mode. The proposed method is verified via a shear-horizontal surface acoustic wave (SH-SAW) resonator based on thin-film lithium niobate-on-insulator (LNOI) topology. Compared with 3D FEM harmonic simulations, the ROM shows an error within +2/-7 dB over a 300 MHz span while shortening the computation time by 14.3 times. The proposed MFIE technique can further reduce the ROM error down to ±2 dB over the same span and provide predictions of the spurious modes that corresponds well to the measured results. © 2023 IEEJ.