Micromachined Resonant Frequency Tuning Unit for Torsional Resonator

Abstract

Achieving the desired resonant frequency of resonators has been an important issue, since it determines their performance. This paper presents the design and analysis of two concepts for the resonant frequency tuning of resonators. The proposed methods are based on the stiffness alteration of the springs by geometrical modification (shaft-widening) or by mechanical restriction (shaft-holding) using micromachined frequency tuning units. Our designs have advantages in (1) reversible and repetitive tuning; (2) decoupled control over the amplitude of the resonator and the tuning ratio; and (3) a wide range of applications including torsional resonators. The ability to tune the frequency by both methods is predicted by finite element analysis (FEA) and experimentally verified on a torsional resonator driven by an electrostatic actuator. The tuning units and resonators are fabricated on a double silicon-on-insulator (DSOI) wafer to electrically insulate the resonator from the tuning units. The shaft-widening type and shaft-holding type exhibit a maximum tuning ratio of 5.29% and 10.7%, respectively.

Analysis of Frequency Drift of Silicon MEMS Resonator with Temperature

“…The oscillator exhibits a frequency drift of 39 ppm over 100 °C as compared to uncompensated frequency drift of 2830 ppm over the same range. Some other works focus on presenting novel structures enlarging the tuning frequency range for temperature drift compensation [ 12 , 13 , 14 ]. Among them, compensation with different materials or additional static-electrical stiffness was mentioned.…”

Monostable Dynamic Analysis of Microbeam-Based Resonators via an Improved One Degree of Freedom Model

“…Microbeam-based structures are widely applied in MEMS, such as microactuator/sensor [ 1 , 2 , 3 ], energy harvester [ 4 ], microresonator [ 5 , 6 , 7 ], gyroscope [ 8 ], microgripper [ 9 , 10 ] and so on. Their light weight, small size, low-energy consumption and durability make them even more attractive.…”

Editorial for the Special Issue on Micro-Resonators: The Quest for Superior Performance

“…Furthermore, the tuning range, frequency stability, and quality factor (Q) of micro-resonators are the focus in References [5,6,7] correspondingly, all of which are of significant practical importance, specifically in oscillator applications. The authors of [5] propose two methods for extending tuning range through stiffness alteration that could be effectively implemented in torsional resonators.…”

“…Furthermore, the tuning range, frequency stability, and quality factor (Q) of micro-resonators are the focus in References [5,6,7] correspondingly, all of which are of significant practical importance, specifically in oscillator applications. The authors of [5] propose two methods for extending tuning range through stiffness alteration that could be effectively implemented in torsional resonators. In Reference [6], frequency stability in response to applied acceleration is investigated in bulk-extensional single crystalline silicon resonators and the dependency of acceleration-sensitivity on the resonator orientation with respect to the silicon crystalline planes are studied through finite element modeling and demonstrated through measurement.…”