High Performance, Continuously Tunable Microwave Filters Using MEMS Devices With Very Large, Controlled, Out-of-Plane Actuation

Future robotic systems will be pervasive technologies operating autonomously in unknown spaces that are shared with humans. Such complex interactions make it compulsory for them to be lightweight, soft, and efficient in a way to guarantee safety, robustness, and long-term operation. Such a set of qualities can be achieved using soft multipurpose systems that combine, integrate, and commute between conventional electromechanical and fluidic drives, as well as harvest energy during inactive actuation phases for increased energy efficiency. Here, we present an electrostatic actuator made of thin films and liquid dielectrics combined with rigid polymeric stiffening elements to form a circular electrostatic bellow muscle (EBM) unit capable of out-of-plane contraction. These units are easy to manufacture and can be arranged in arrays and stacks, which can be used as a contractile artificial muscle, as a pump for fluid-driven soft robots, or as an energy harvester. As an artificial muscle, EBMs of 20 to 40 millimeters in diameter can exert forces of up to 6 newtons, lift loads over a hundred times their own weight, and reach contractions of over 40% with strain rates over 1200% per second, with a bandwidth over 10 hertz. As a pump driver, these EBMs produce flow rates of up to 0.63 liters per minute and maximum pressure head of 6 kilopascals, whereas as generator, they reach a conversion efficiency close to 20%. The compact shape, low cost, simple assembling procedure, high reliability, and large contractions make the EBM a promising technology for high-performance robotic systems.

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Mechanism of the Transition From In-Plane Buckling to Helical Buckling for a Stiff Nanowire on an Elastomeric Substrate

Journal of Applied Mechanics ◽

10.1115/1.4032573 ◽

2016 ◽

Vol 83 (4) ◽

Cited By ~ 17

Author(s):

Youlong Chen ◽

Yong Zhu ◽

Xi Chen ◽

Yilun Liu

Keyword(s):

High Performance ◽

Three Dimensional ◽

Stretchable Electronics ◽

Buckling Mode ◽

Design And Optimization ◽

Out Of Plane ◽

Plane Direction ◽

Plane Displacement ◽

Helical Buckling ◽

Selection Of

In this work, the compressive buckling of a nanowire partially bonded to an elastomeric substrate is studied via finite-element method (FEM) simulations and experiments. The buckling profile of the nanowire can be divided into three regimes, i.e., the in-plane buckling, the disordered buckling in the out-of-plane direction, and the helical buckling, depending on the constraint density between the nanowire and the substrate. The selection of the buckling mode depends on the ratio d/h, where d is the distance between adjacent constraint points and h is the helical buckling spacing of a perfectly bonded nanowire. For d/h > 0.5, buckling is in-plane with wavelength λ = 2d. For 0.27 < d/h < 0.5, buckling is disordered with irregular out-of-plane displacement. While, for d/h < 0.27, buckling is helical and the buckling spacing gradually approaches to the theoretical value of a perfectly bonded nanowire. Generally, the in-plane buckling induces smaller strain in the nanowire, but consumes the largest space. Whereas the helical mode induces moderate strain in the nanowire, but takes the smallest space. The study may shed useful insights on the design and optimization of high-performance stretchable electronics and three-dimensional complex nanostructures.

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Actuation Behavior of Multilayer Graphene Nanosheets/Polydimethylsiloxane Composite Films

Polymers ◽

10.3390/polym10111243 ◽

2018 ◽

Vol 10 (11) ◽

pp. 1243 ◽

Cited By ~ 5

Author(s):

Chunmei Zhang ◽

Tianliang Zhai ◽

Chao Zhan ◽

Qiuping Fu ◽

Chao Ma

Keyword(s):

Composite Film ◽

High Performance ◽

Graphene Nanosheets ◽

Composite Films ◽

Multilayer Graphene ◽

Layer By Layer ◽

Pdms Film ◽

Out Of Plane ◽

Dielectric Actuation ◽

Electromechanical Actuation

The graphene nanosheets (GNS)/polydimethylsiloxane (PDMS) composite films with out-of-plane dielectric actuation behavior were prepared through a layer-by-layer spin coating process. The GNS-PDMS/PDMS composite films with 1~3 layers of GNS-PDMS films were spin coated on top of the PDMS film. The dielectric, mechanical, and electromechanical actuation properties of the composite films were investigated. The dielectric constant of the GNS-PDMS3/PDMS composite film at 1 kHz is 5.52, which is 1.7 times that of the GNS-PDMS1/PDMS composite film. The actuated displacement of the GNS-PDMS/PDMS composite films is greatly enhanced by increasing the number of GNS-PDMS layers. This study provides a novel alternative approach for fabricating high-performance actuators with out-of-plane actuation behavior.

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REPLICATION OF NANO/MICRO QUARTZ MOLD BY HOT EMBOSSING AND ITS APPLICATION TO BOROSILICATE GLASS EMBOSSING

International Journal of Modern Physics B ◽

10.1142/s0217979208051674 ◽

2008 ◽

Vol 22 (31n32) ◽

pp. 6118-6123 ◽

Cited By ~ 1

Author(s):

SUNG-WON YOUN ◽

CHIEKO OKUYAMA ◽

MASHARU TAKAHASHI ◽

RYUTARO MAEDA

Keyword(s):

High Performance ◽

Focused Ion Beam ◽

Ion Beam ◽

Hot Embossing ◽

High Fidelity ◽

Borosilicate Glasses ◽

Mems Devices ◽

Barrier Layers ◽

Multiple Copies ◽

Micro Electromechanical System

Glass hot-embossing is one of essential techniques for the development of high-performance optical, bio, and chemical micro electromechanical system (MEMS) devices. This method is convenient, does not require routine access to clean rooms and photolithographic equipment, and can be used to produce multiple copies of a quartz mold as well as a MEMS component. In this study, quartz molds were prepared by hot-embossing with the glassy carbon (GC) masters, and they were applied to the hot-emboss of borosilicate glasses. The GC masters were prepared by dicing and focused ion beam (FIB) milling techniques. Additionally, the surfaces of the embossed quartz molds were coated with molybdenum barrier layers before embossing borosilicate glasses. As a result, micro-hot-embossed structures could be developed in borosilicate glasses with high fidelity by hot embossing with quartz molds.

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Numerical analysis of stiffened plates subjected to transverse uniform load through the constructal design method

Engineering Solid Mechanics ◽

10.5267/j.esm.2021.9.001 ◽

2022 ◽

Vol 10 (1) ◽

pp. 99-108 ◽

Cited By ~ 1

Author(s):

Vinícius Torres Pinto ◽

Luiz Alberto Oliveira Rocha ◽

Elizaldo Domingues dos Santos ◽

Liércio André Isoldi

Keyword(s):

High Performance ◽

Design Method ◽

Material Constant ◽

Stiffened Plates ◽

The Finite Element Method ◽

Uniform Load ◽

Constructal Design ◽

Geometric Configurations ◽

Out Of Plane ◽

Do So

When it comes to engineering, high performance is always a desired goal. In this context, regarding stiffened plates, the search for better geometric configurations able to minimize the out-of-plane displacements become interesting. So, this study aimed to analyze several stiffened plates defined by the Constructal Design Method (CDM) and solved through the Finite Element Method (FEM) using the ANSYS® software. After that, these plates are compared among each other through the Exhaustive Search (ES) technique. To do so, a non-stiffened rectangular plate was adopted as reference. Then, a portion of its steel volume was converted into stiffeners through the ϕ parameter, which represents the ratio between the volume of the stiffeners and the total volume of the reference plate. Taking into consideration the value of ϕ = 0.3, 75 different stiffened plates arrangements were proposed: 25 with rectangular stiffeners oriented at 0°; 25 with rectangular stiffeners oriented at 45° and 25 with trapezoidal stiffeners oriented at 0°. Maintaining the total volume of material constant, it was investigated the geometry influence on the maximum deflection of these stiffened plates. The results have shown trapezoidal stiffeners oriented at 0° are more effective to reduce the maximum deflections than rectangular stiffeners also oriented at 0°. It was also observed that rectangular stiffeners oriented at 45° presented the smallest maximum deflections for the majority of the analyzed cases, when compared to the trapezoidal and rectangular stiffeners oriented at 0°.

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Flexible and tunable microwave filters based on arrayed waveguide gratings

International Topical Meeting on Microwave Photonics MWP-02 ◽

10.1109/mwp.2002.1158895 ◽

2002 ◽

Cited By ~ 5

Author(s):

Pastor ◽

Ortega ◽

Capmany ◽

Sales ◽

Martinez ◽

...

Keyword(s):

Microwave Filters ◽

Arrayed Waveguide Gratings ◽

Tunable Microwave ◽

Waveguide Gratings ◽

Arrayed Waveguide

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Stability Analysis of Spin-Torque Nano-oscillator in the Rotating Frame

SPIN ◽

10.1142/s2010324719500085 ◽

2019 ◽

Vol 09 (03) ◽

pp. 1950008

Author(s):

HaoHsuan Chen ◽

Lang Zeng ◽

ChingMing Lee ◽

Weisheng Zhao

Keyword(s):

High Performance ◽

Electrical Current ◽

Nonstationary Process ◽

Laboratory Frame ◽

Spin Torque ◽

Rotating Frame ◽

Magnetization Dynamics ◽

Applied Current ◽

Frequency Tunability ◽

Out Of Plane

Spin-torque nano-oscillators (STNOs) have become one of the emerging and novel microwave devices with the high performance and tunability of GHz range frequency. The nanopillar structure with an out-of-plane (OP) spin polarizer and an in-plane (IP) magnetized free layer (FL) has been considered as a good candidate for the STNOs. Using the local rotational coordinate transformation, a nonstationary process describing magnetization dynamics in the laboratory frame is therefore transformed into a stationary one in the rotating frame. In this way, the state phase diagram of this type of STNOs is well established as a function of an applied current and external field, which is also evidenced by the macrospin simulations. Also, we show that the frequency tunability of the STNOs through electrical current can be well elevated by applying a static magnetic field anti-parallel to the spin-polarizer vector.

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A In Situ Measuring Method for Stress Gradient of a MEMS Film

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.60-61.357 ◽

2009 ◽

Vol 60-61 ◽

pp. 357-360 ◽

Cited By ~ 3

Author(s):

Han Chen ◽

Hua Rong ◽

Ming Wang

Keyword(s):

Thin Film ◽

Circular Plate ◽

Stress Gradient ◽

Measuring Method ◽

Mechanical Parameter ◽

Curvature Radius ◽

Mems Devices ◽

Out Of Plane

The stress gradient of a deposited thin-film is a mechanical parameter that affects the performance of MEMS devices, so in-situ measuring stress gradient of a thin-film is great significant. A new in-situ measuring method based on a center-anchored circular plate is presented. The Mirau interferometer has been used to measure the out-of-plane height at the edge of circular plate, then the curvature radius of the plate and the stress gradient of the film can be calculated. The measuring method has been verified by CoventorWare. The accuracy of the presented measuring method is ideal. The advantages of the method also have been discussed.

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Characterization of the Dynamical Response of a Micromachined G-Sensor to Mechanical Shock Loading

Volume 1: 21st Biennial Conference on Mechanical Vibration and Noise, Parts A, B, and C ◽

10.1115/detc2007-34843 ◽

2007 ◽

Author(s):

Daniel E. Jordy ◽

Mohammad I. Younis

Keyword(s):

Finite Element ◽

Finite Element Model ◽

Element Model ◽

Squeeze Film ◽

Dynamical Response ◽

Mems Devices ◽

Damping Coefficients ◽

Squeeze Film Damping ◽

Out Of Plane ◽

Gap Width

Squeeze film damping has a significant effect on the dynamic response of MEMS devices that employ perforated microstructures with large planar areas and small gap widths separating them from the substrate. Perforations can alter the effect of squeeze film damping by allowing the gas underneath the device to easily escape, thereby lowering the damping. By decreasing the size of the holes, the damping increases and the squeeze film damping effect increases. This can be used to minimize the out-of-plane motion of the microstructures toward the substrate, thereby minimizing the possibility of contact and stiction. This paper aims to explore the use of the squeeze-film damping phenomenon as a way to mitigate shock and minimize the possibility of stiction and failure in this class of MEMS devices. As a case study, we consider a G-sensor, which is a sort of a threshold accelerometer, employed in an arming and fusing chip. We study the effect of changing the size of the perforation holes and the gap width separating the microstructure from the substrate. We use a multi-physics finite-element model built using the software ANSYS. First, a modal analysis is conducted to calculate the out-of-plane natural frequency of the G-sensor. Then, a squeeze-film damping finite-element model, for both the air underneath the structure and the flow of the air through the perforations, is developed and utilized to estimate the damping coefficients for several hole sizes. Results are shown for various models of squeeze-film damping assuming no holes, large holes, and assuming a finite pressure drop across the holes, which is the most accurate way of modeling. The extracted damping coefficients are then used in a transient structural-shock analysis. Finally, the transient shock analysis is used to determine the shock loads that induce contacts between the G-sensor and the underlying substrate. It is found that the threshold of shock to contact the substrate has increased significantly when decreasing the holes size or the gap width, which is very promising to help mitigate stiction in this class of devices, thereby improving their reliability.

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