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Modal Coupling Effect in a Novel Nonlinear Micromechanical Resonator.
Kuo Lu1, Qingsong Li1, Xin Zhou1
1College of Intelligence Science and Technology, National University of Defense Technology, Changsha 410073, China.
Micromachines
|May 6, 2020
Summary
This study explores electrostatic modal coupling in capacitive micromechanical resonators, focusing on the stiffness hardening region. It demonstrates significant frequency tuning by activating a cavity mode, offering wide-ranging applications.
Area of Science:
- Microelectromechanical Systems (MEMS)
- Nonlinear Dynamics
- Solid State Physics
Background:
- Capacitive micromechanical resonators exhibit electrostatic coupling between modes due to shared electrodes and bias voltage.
- Electrostatic coupling, dependent on electric potential energy, typically occurs in nonlinear operating regions.
- Prior research predominantly examined stiffness softening, neglecting the stiffness hardening regime.
Purpose of the Study:
- Investigate electrostatic modal coupling within the stiffness hardening region of capacitive resonators.
- Design and fabricate a novel capacitive micromechanical resonator with distinct modal nonlinearities.
- Analyze the impact of activating a cavity mode on the manipulated mode's resonance frequency.
Main Methods:
- Fabrication of a novel capacitive micromechanical resonator.
- Experimental activation of a cavity mode within the resonator.
- Measurement and analysis of resonance frequency shifts and nonlinear behaviors.
Main Results:
- Activating a cavity mode induced a significant frequency shift (approx. 90 times mechanical bandwidth) in the fundamental resonance of the manipulated mode.
- The direction of frequency shifting correlated with the manipulated mode's nonlinearity.
- Frequency hopscotch behavior was determined by the cavity mode's nonlinearity.
Conclusions:
- Electrostatic coupling offers an efficient and tunable method for wide-range frequency tuning in capacitive resonators.
- The presented modal coupling theory is applicable to various capacitive resonators, aiding performance enhancement.
- This work highlights the potential of electrostatic coupling in the stiffness hardening region for advanced resonator applications.
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