Electromechanical Modelling and Stress Analysis of RF-MEMS Capacitive Shunt Switch

2021 ◽  
Author(s):  
Gopichand Ch ◽  
Reshmi Maity ◽  
K. Srinivas ◽  
N.P. Maity ◽  
K. Girija Srav
Keyword(s):  
Residual Stress ◽  
Stress Analysis ◽  
Maximum Stress ◽  
Rf Mems ◽  
Stress Gradient ◽  
Membrane Structures ◽  
Mechanical Modelling ◽  
Calculation Results ◽  
Beam Thickness ◽  
Center Deflection

Abstract This paper presents the simulation and theoretically calculation results of a shunt switch with Electro-mechanical modelling and stress gradient characteristics. The analysis is done with three membrane structures such as plane beam, incorporated with and without perforations, and non-uniform meander type beam, these are simulated in the COMSOL Multi-physics tool. The various Modal analyses are carried out for different values of residual stress gradients such as different structures, materials, and beam thickness. These analyzes are described by the fact that higher stress gradient values ​​are undesirable for switching. By analysing all the results we have observed that the stress analysis for a shows that non-uniform meandered switch experiences maximum stress of 35.6 MPa, and center deflection of 0.06 MPa/μm, the deformations of the beam which is the least among the considered switches.

Non-Destructive Residual Stress Analysis of Induction Hardened Components by Neutron and X-Ray Diffraction

2013 ◽  
Vol 768-769 ◽  
pp. 420-427 ◽  
Author(s):  
Jeremy Epp ◽  
Thilo Pirling ◽  
Thomas Hirsch
Keyword(s):  
Residual Stress ◽  
Chemical Composition ◽  
Residual Stresses ◽  
Stress Analysis ◽  
Stress Gradient ◽  
X Ray Diffraction ◽  
Neutron Measurement ◽  
X Ray ◽  
Layer Removal ◽  
Residual Stress Analysis

In this paper the microstructural and residual-stress analysis of an induction hardened plate of medium carbon steel is described. The stress gradient was determined using laboratory X-ray diffraction (IWT, Bremen, Germany) and neutron strain scanning (ILL, Grenoble, France). Due to slight variations of chemical composition in the depth, matchstick like (cross section 2×2mm²) d0-reference samples were prepared from a similarly treated sample. The d0shift induced by variation of chemical composition was measured by neutron and by X-ray diffraction along the strain free direction (sin²ψ*) and used for the evaluation of the neutron stress calculation. The d0distribution obtained from the neutron measurement did not appear reliable while the method using X-ray diffraction seems to be an efficient and reliable method to determine d0profiles in small samples. The evaluation of neutron measurements was then done using the X-ray diffraction d0distribution. High compressive residual stresses were measured in the hardened layer followed by high tensile residual stresses in the core. A comparison of the neutron measurements with X-ray diffraction (XRD) depth profiles obtained after successive layer removal showed that both methods give similar results. However, these investigations opened the question about the direct comparison of the residual stresses obtained by neutron and XRD. Indeed, a correction of the neutron data regarding the residual stresses in thickness direction might be necessary as these are released in the case of X-ray diffraction measurements after layer removal.

scholarly journals Novel RF MEMS tunable capacitors

2021 ◽  
Author(s):  
Zewdu Hailu
Keyword(s):  
Residual Stress ◽  
Rf Mems ◽  
Stress Gradient ◽  
Repulsive Force ◽  
Quality Factors ◽  
Comb Drive ◽  
Moving Plate ◽  
Tunable Capacitor ◽  
Tunable Capacitors ◽  
Residual Stress Gradient

Current tunable devices such as filters, impedance matching networks and oscillators have problems that degrade their performance at high microwave frequencies. Tuning ratios and quality factors are the major problems associated with semiconductor based tuning components. This thesis presents the design, fabrication and testing of two novel RF MEMS tunable capacitors. The first tunable capacitor is designed using electrostatic repulsive-force actuators which produce an upward movement of the moving plate of a tunable capacitor. The repulsive-force actuator is free of pull-in effect and capable of reaching large displacement. Gap increasing tunable capacitors with areas of 162μm×220μm and 300μm×302μm are developed using electrostatic repulsive-force actuators. The capacitances are calculated using simulations and maximum tuning ratios of 438.5% and 230% are obtained for a parallel and inclined plate designs, respectively, with capacitance-voltage linearity of 96.28% and 95.14%, respectively, in the presence of RF voltage. The second tunable capacitor is developed using residual stress gradient based vertical comb-drive actuator. Conventional vertical comb-drive actuators need two vertical comb fingers, i.e., one for the fixed and one for the moving comb. MetalMUMPs process provides a 20μm thick nickel layer which is subject to residual stress gradient along its thickness. Using the residual stress gradient two curve-up beams are devised to bend out of plane and upward. A moving plate is connected between the middles of the curve-up beams through supporting springs and is raised above the substrate. The moving fingers are connected to opposite sides of the moving plate. The fixed comb-drive fingers are anchored to the substrate. When a voltage is applied, the moving fingers move down towards the fixed fingers. As a result, the capacitance between the moving fingers and the fixed fingers change. Prototypes are fabricated to verify the working principles of this novel actuator using the MetalMUMPs process. Tunable capacitors based on this actuator are experimentally analyzed. Quality factors of 106.9-162.7 at 0.8GHz and 42.4-51.9 at 1.24GHz are obtained over actuation voltage of 0-100V. An optimal design of the tunable capacitors achieved a tuning ratio of 194.4% at 162.5V with linearity of 97.84%

Influence of Shot-Peening Parameters on the Sub-Surface Residual Stress Profiles in Al-7075 Alloy Components

2013 ◽  
Vol 768-769 ◽  
pp. 66-71 ◽  
Author(s):  
Diego Cecchin ◽  
Cristy Leonor Azanza Ricardo ◽  
Mirco D'Incau ◽  
Michele Bandini ◽  
Paolo Scardi
Keyword(s):  
Residual Stress ◽  
Stress Analysis ◽  
Shot Peening ◽  
Stress Gradient ◽  
Stress Profile ◽  
Surface Residual Stress ◽  
X Ray ◽  
Al 7075 ◽  
Stress Profiles ◽  
Residual Stress Analysis

Aluminum alloy (Al-7075-T6) samples were analyzed to determine the in-depth residual stress profile induced by a shot-peening treatment. The influence of coverage degree and Almen intensity on the surface residual stress and on the sub-surface residual stress gradient was investigated. Residual stress profiles were obtained using three different techniques: (i) standard laboratory X-ray diffraction (XRD) residual stress analysis with progressive chemical layer-removal; (ii) XRD residual stress analysis with synchrotron radiation using different X-ray energies, thus changing the penetration depths, and (iii) Blind Hole Drilling (BHD). A comprehensive comparison of the results given by the used techniques is shown.

scholarly journals Novel RF MEMS tunable capacitors

2021 ◽  
Author(s):  
Zewdu Hailu
Keyword(s):  
Residual Stress ◽  
Rf Mems ◽  
Stress Gradient ◽  
Repulsive Force ◽  
Quality Factors ◽  
Comb Drive ◽  
Moving Plate ◽  
Tunable Capacitor ◽  
Tunable Capacitors ◽  
Residual Stress Gradient

Current tunable devices such as filters, impedance matching networks and oscillators have problems that degrade their performance at high microwave frequencies. Tuning ratios and quality factors are the major problems associated with semiconductor based tuning components. This thesis presents the design, fabrication and testing of two novel RF MEMS tunable capacitors. The first tunable capacitor is designed using electrostatic repulsive-force actuators which produce an upward movement of the moving plate of a tunable capacitor. The repulsive-force actuator is free of pull-in effect and capable of reaching large displacement. Gap increasing tunable capacitors with areas of 162μm×220μm and 300μm×302μm are developed using electrostatic repulsive-force actuators. The capacitances are calculated using simulations and maximum tuning ratios of 438.5% and 230% are obtained for a parallel and inclined plate designs, respectively, with capacitance-voltage linearity of 96.28% and 95.14%, respectively, in the presence of RF voltage. The second tunable capacitor is developed using residual stress gradient based vertical comb-drive actuator. Conventional vertical comb-drive actuators need two vertical comb fingers, i.e., one for the fixed and one for the moving comb. MetalMUMPs process provides a 20μm thick nickel layer which is subject to residual stress gradient along its thickness. Using the residual stress gradient two curve-up beams are devised to bend out of plane and upward. A moving plate is connected between the middles of the curve-up beams through supporting springs and is raised above the substrate. The moving fingers are connected to opposite sides of the moving plate. The fixed comb-drive fingers are anchored to the substrate. When a voltage is applied, the moving fingers move down towards the fixed fingers. As a result, the capacitance between the moving fingers and the fixed fingers change. Prototypes are fabricated to verify the working principles of this novel actuator using the MetalMUMPs process. Tunable capacitors based on this actuator are experimentally analyzed. Quality factors of 106.9-162.7 at 0.8GHz and 42.4-51.9 at 1.24GHz are obtained over actuation voltage of 0-100V. An optimal design of the tunable capacitors achieved a tuning ratio of 194.4% at 162.5V with linearity of 97.84%

Neutron Surface Residual Stress Scanning Using Optimisation of a Si Bent Perfect Crystal Monochromator for Minimising Spurious Strains

2011 ◽  
Vol 681 ◽  
pp. 399-404 ◽  
Author(s):  
Joana Rebelo-Kornmeier ◽  
Jens Gibmeier ◽  
Michael Hofmann ◽  
Robert C. Wimpory
Keyword(s):  
Residual Stress ◽  
Stress Analysis ◽  
Surface Effect ◽  
Stress Gradient ◽  
High Energy ◽  
Surface Strain ◽  
X Rays ◽  
Surface Residual Stress ◽  
Gauge Volume ◽  
Residual Strains

For non destructive stress analysis of surface treated steel samples the application of laboratory X rays or high energy synchrotron radiation in reflection mode covers the region from some micrometers up to a depth of about 150 - 200 µm. To access depth regions deeper than 200 µm the incremental layer removal technique in combination with the repeated application of X‑ray stress analysis for the newly generated surfaces can be used. However, this procedure is destructive, laborious and furthermore, it has to be checked whether corrections have to be applied due to stress relaxation. By using neutron radiation penetration depths generally up to several millimetres can be achieved non destructively [1]. However neutron measurements are critical at the surface. When scanning a sample surface, aberration peak shifts caused by so called spurious strains arise due to the fact that the gauge volume defined by the primary and secondary optics is partially outside of the sample. These aberration peak shifts can be of the same order of magnitude as the peak shifts related to residual strains [2-6]. In this exemplary study it will be demonstrated that, by optimising the bending radius of a Si (400) monochromator, the spurious surface strains can be strongly reduced when compared to the values obtained with a traditional Ge (311) mosaic monochromator, even when the gauge volume is mainly out of the surface. The objective of the experiments is to find the optimal monochromator settings for the Si (400) monochromator at the STRESS-SPEC instrument at the research reactor FRM II, Munich, Germany. For the parametric studies a stress free steel sample of the fine grained construction steel, S690QL was used. The optimised conditions for the Si (400) monochromator that resulted from the systematic studies were applied to a shot peened plate of steel SAE 4140. The residual stress distribution is analysed by means of through surface strain scanning. The residual stress gradient obtained is in very good agreement with the well characterised residual stress depth profile obtained within a round robin test in the scope of the BRITE-EURAM-project ENSPED (European Network of Surface and Prestress Engineering and Design) [7]. The results indicated that surface residual stress profiles can be measured with neutrons up to 200 µm underneath the surface without time consuming and laborious surface effect corrections.

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