Frequency Stabilization in Non-linear MEMS and NEMS Oscillators (IN-11-087)
A New Strategy for Engineering Low-Frequency Noise Oscillators
SEM image of one resonator used in our studies (center) and Finite Element Simulations of the dynamic deformation characteristics of the coupled vibrational modes (left and right side).
Mechanical oscillators are an important component in electronic devices and they represent a multi-billion dollar industry. As electronics become increasingly miniaturized, oscillators must become smaller as well and this makes them more sensitive to environmental variations. Scientists at Argonne National Laboratory have devised a method to solve this problem that allows creating micro and nano mechanical oscillators with excellent frequency stability.Description
Almost every electronic device contains a mechanical oscillator—a component whose chief function is to resonate at a predetermined frequency over a specific period of time. Historically, most oscillators have used a quartz crystal as the resonating element, but increasingly, micromechanical resonators are replacing crystals because of their small size, simpler fabrication and reduced cost. However, as these resonators are made smaller, they become less stable and more sensitive to environmental changes.
A team of Argonne scientists has developed a method to make the micro/nano oscillators ultra stable by coupling two vibrational modes through an internal resonance. This coupling stabilizes the oscillation frequency of nonlinear self-sustaining micromechanical resonators. The energy exchange of the two coupled modes is such that the resonance of one mode absorbs the amplitude and frequency fluctuations of the other, acting as a stabilizing mechanical negative feedback loop. The team’s findings provide a new strategy for engineering low-frequency noise oscillators, capitalizing on the intrinsic nonlinear phenomena of micromechanical resonators.Benefits
Argonne’s new method offers a new strategy for further optimizing and engineering micro- and nanoscale devices and shows that very low frequency noise performance is possible in the nonlinear regime of mechanical resonators.Applications and Industries
- Timing references: GPS, synchronization, frequency references
- Nano- and micromechanical oscillators
- Frequency-shift-based detectors
- Mechanical energy storage
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Frequency Stabilization in Nonlinear MEMS and NEMS Oscillators
An illustrative system includes an amplifier operably connected to a phase shifter. The amplifier is configured to amplify a voltage from an oscillator. The phase shifter is operably connected to a driving amplitude control, wherein the phase shifter is configured to phase shift the amplified voltage and is configured to set an amplitude of the phase shifted voltage. The oscillator is operably connected to the driving amplitude control. The phase shifted voltage drives the oscillator. The oscillator is at an internal resonance condition, based at least on the amplitude of the phase shifted voltage, that stabilizes frequency oscillations in the oscillator.
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