Analysis of Loss Mechanisms and Frequency Mismatch in Microelectromechanical Systems (MEMS)-Based Resonators

Date of Award

Summer 2021

Publication Type

Thesis

Degree Name

M.A.Sc.

Department

Mechanical, Automotive, and Materials Engineering

Keywords

Mode matching, Resonator, Sensitivity, Loss mechanisms, Frequency mismatch, Microelectromechanical Systems, Micromachining technology

Supervisor

J. Ahamed

Supervisor

S. Alirezaee

Rights

info:eu-repo/semantics/openAccess

Abstract

A Microelectromechanical System (MEMS) is based on Microelectronic Technique and Micromachining technology. The mechanical systems and electrical components can be built at a micro-scale. The systems can interact with each other by using the combination of those two technologies. MEMS gyroscopes are made up of proof masses, electrodes, springs, anchors, actuators, and detectors. The advantages of MEMS devices are reducing the size, weight, energy usage, and cost while maintaining the functionality of the sensors. Sensitivity is an important parameter to evaluate the performance of a gyroscope. This thesis performed the springs modelling technique to maximize the sensitivity of a vibratory MEMS resonator. This thesis investigates the relationship between the geometric variation of springs and frequency split. The frequency split was determined by using COMSOL simulation. The frequency can be tuned by changing the length and width of the springs. A length of springs tuned to 1834.8 µm resulted in a frequency split of 0 Hz. The results demonstrated that the geometric variation in springs makes a significant difference in frequency split and sensitivity of the gyroscope. Three different geometries were designed, and the one with the best performance was selected. A sensitivity calculation was performed by investigating the quality factor. The overall Q factor can be calculated as 6269.5 and 2705.5 for drive mode and sense modes, respectively. The model simulation showed a sensitivity of 2.22*10-8 m/deg/s for a frequency split of 0 Hz by optimizing the springs’ lengths. The fabrication platform selected was PolyMUMPS, which is cost effective and versatile. The experimental testing was not performed due to the global shortage of material caused by the pandemic.

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