Electromechanical parametric resonator (Technion)
Electrostatic resonators are building blocks in filters, sensors, oscillators and many other devices. Linear electrostatic resonators commonly have a high quality factor, making their resonance peak sharp. A very high sensitivity to frequency may also be obtained from nonlinear resonators. It is well known that for some classic cases of parametric resonators, the stable periodic response becomes unstable at extremely narrow windows of driving frequency. It is therefore very appealing to harness this property of parametric resonators for producing high sensitivity sensors and high accuracy oscillators. The problem is that up to date, it is impossible to produce a perfect parametric resonator because no one has found a way to produce a time-varying stiffness without introducing additional effects such as time varying forces. The current strategy of using small AC signals and ensuring that output is small, limits the sensitivity of the systems.The essence of a resonator is that it strongly attenuates excitations in all but a selective narrow band of frequencies. Resonators are therefore prevalent as filters. Resonators can also be used as oscillators by adding a mechanism that locks in to their frequency of peak response. For a simple linear mechanical resonator, the maximal amplitude of velocity occurs at the resonance frequency when the mass is subjected to a harmonic force. To the best of our knowledge, no one has yet presented a device or suggested a design of a perfect parametric resonator. The presented invention is a resonator in which stiffness is time-varying and no other forces are applied. The innovative design is a double-sided comb-drive actuator which has a symmetric architecture and has a graded overlap between the fingers of the rotor and stator. This actuator is driven by applying an AC signal to the rotor while both stators are grounded.
• First electromechanical resonator to produce a perfect response (i.e. harmonic modification of stiffness with no application of driving forces at all)
• Combines the flexibility of electric actuation, sensing and processing, with the high quality factor typical of elastically deformable structures at the micro-scale
• High efficiency filters (e.g. for RF signals),
• Ultra-sensitive sensors (e.g. chemical and biological substances)
• Accurate oscillators for clocking devices (i.e. replacement of quartz crystals)
COM-1470
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