Capacitance based tunable resonators

Adams, Scott G.; Bertsch, F.M.; Shaw, K.A.; Hartwell, P.G.; Moon, Francis C.; MacDonald, N.C.

doi:10.1088/0960-1317/8/1/003

Cited by 60 publications

(34 citation statements)

References 19 publications

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“…However, a transduction mechanism for the effective conversion between the electrical and mechanical forms of the signal remains one of the key problems in MEMS design. The widely used capacitive drive 8 imposes restrictions related to cross talk issues and to high voltages required for actuation. Piezoelectric 9 or magnetomotive 10 actuation cannot be readily integrated because of the requirement for integrated circuit ͑IC͒-incompatible materials or high magnetic fields.…”

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confidence: 99%

Shell-type micromechanical actuator and resonator

Zalalutdinov

Aubin

Reichenbach

et al. 2003

Applied Physics Letters

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Dome-shaped radio-frequency micromechanical resonators were fabricated by utilizing the buckling of a prestressed thin polysilicon film. The enhanced rigidity of the dome structure leads to a significant increase of its resonant frequency compared to a flat plate resonator. The shell-type geometry of the structure also provides an imbedded actuation mechanism. Significant out-of plane deflections are actuated by mechanical stress introduced within the plane of the shell. We demonstrate that thermomechanical stress generated by a focused laser beam, or microfabricated resistive heater, provides an effective and fast mechanism to operate the dome as an acoustic resonator in the radio-frequency range. All-optical operation of the shell resonator and an integrated approach are discussed. © 2003 American Institute of Physics. ͓DOI: 10.1063/1.1622792͔ High-frequency microelectromechanical systems ͑MEMS͒ are widely considered as an element base for signal processing in the next generation of wireless communication devices. 1-3 Parametric amplification, 4,5 limit cycle oscillations, 6 and injection locking 7 demonstrated for MEMS oscillators allows one to build active circuits where signal processing would be implemented in the mechanical domain. However, a transduction mechanism for the effective conversion between the electrical and mechanical forms of the signal remains one of the key problems in MEMS design. The widely used capacitive drive 8 imposes restrictions related to cross talk issues and to high voltages required for actuation. Piezoelectric 9 or magnetomotive 10 actuation cannot be readily integrated because of the requirement for integrated circuit ͑IC͒-incompatible materials or high magnetic fields.In this letter, we demonstrate a design for a rf MEMS resonator based on the geometry of a shallow segment of a thin spherical shell. The finite curvature of the shell introduces an imbedded actuation mechanism by coupling the in-plane stress to the out-of-plane deflection of the shell. 11 The key feature of the shell actuation mechanism described in this letter is the local nature of the driving stress introduced at a specific point of the shell. A similar approach is employed in the design of macroscopic induced-strain actuators, 12,13 for ''smart structures'' actuated by small piezoelectric patches, surface bonded on a cylindrical shell at certain locations.In our micromechanical shell actuator, the in-plane strain is provided by stress introduced directly inside the shell layer. In our experiments we employ thermoelastic stress created by heating of the shell either by using a focused laser beam or a microfabricated heater. Using local heating, one can actuate cantilevering shell or bowl-type structures ͑shells supported at the center point͒. In the latter case, the compressive stress applied in the hoop direction close to the free edge of the shell flattens the bowl and provides a vertical component to the deflection of the periphery. The resulting motion can be complicated; thus for the configuration cons...

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confidence: 99%

Shell-type micromechanical actuator and resonator

Zalalutdinov

Aubin

Reichenbach

et al. 2003

Applied Physics Letters

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“…These actuators can be made active or intermittently active (also called passive) [5], maintaining resonant frequency also during inactive periods. Examples of active actuators are electrostatic elastomers [6], while passive actuators can be various types of bending mechanisms. The role of actuators is to deliver an additional force that varies with displacement (acting on stiffness) or acceleration (acting on mass), but the amplitude of the force also depends on other aspects, such as how the force is applied [5], [6].…”

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confidence: 99%

Vibration Energy Harvesting Potential for Turbomachinery Applications

Stoicescu¹,

Deaconu²,

Dorin³

et al. 2018

INCAS BULLETIN

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The vibration energy harvesting process represents one of the research directions for increasing power efficiency of electric systems, increasing instrumentation nodes autonomy in hard to reach locations and decreasing total system mass by eliminating cables and higher-power adapters. Research based on the possibility of converting vibration energy into useful electric energy is used to evaluate the potential of its use on turbomachinery applications. Aspects such as the

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“…2 the consequence of pull-in is that the structure hits Y. Zhang State Key Laboratory of Nonlinear Mechanics (LNM), Institute of Mechanics, Chinese Academy of Science, Beijing 100190, China the electrode and adheres to it (Francais et al 1997;Zhang et al 2007). The snap-through and pull-in instabilities are the same type of instability termed as fold catastrophe (Thompson 1982), which in energy perspective involves the coalescence and extinction of a minimum and a maximum (Adams et al 1998;Thompson 1982). Here, the pull-in instability is defined as the one that the structure collides with electrode and the snap-through instability is the one without collision.…”

Section: Introductionmentioning

confidence: 99%

Analytical method of predicating the instabilities of a micro arch-shaped beam under electrostatic loading

Zhang

Wang

2010

Microsyst Technol

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An arch-shaped beam with different configurations under electrostatic loading experiences either the direct pull-in instability or the snap-through first and then the pull-in instability. When the pull-in instability occurs, the system collides with the electrode and adheres to it, which usually causes the system failure. When the snapthrough instability occurs, the system experiences a discontinuous displacement to flip over without colliding with the electrode. The snap-through instability is an ideal actuation mechanism because of the following reasons: (1) after snap-through the system regains the stability and capability of withstanding further loading; (2) the system flips back when the loading is reduced, i.e. the system can be used repetitively; and (3) when approaching snapthrough instability the system effective stiffness reduces toward zero, which leads to a fast flipping-over response. To differentiate these two types of instability responses for an arch-shaped beam is vital for the actuator design. For an arch-shaped beam under electrostatic loading, the nonlinear terms of the mid-plane stretching and the electrostatic loading make the analytical solution extremely difficult if not impossible and the related numerical solution is rather complex. Using the one mode expansion approximation and the truncation of the higher-order terms of the Taylor series, we present an analytical solution here. However, the one mode approximation and the truncation error of the Taylor series can cause serious error in the solution. Therefore, an error-compensating mechanism is also proposed. The analytical results are compared with both the experimental data and the numerical multi-mode analysis. The analytical method presented here offers a simple yet efficient solution approach by retaining good accuracy to analyze the instability of an arch-shaped beam under electrostatic loading.

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Capacitance based tunable resonators

Cited by 60 publications

References 19 publications

Shell-type micromechanical actuator and resonator

Shell-type micromechanical actuator and resonator

Vibration Energy Harvesting Potential for Turbomachinery Applications

Analytical method of predicating the instabilities of a micro arch-shaped beam under electrostatic loading

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