MEMS

دسترسی آزاد مقاله

1 - شبکه موبایل GSM و مشکلات امنیتی آن
محمد امیر قاسمی شبانکاره سارا رحیمی جوانمردی

با توجه به افزایش ارتباطات ، شبکه های موبایل روز به روز در حال گسترش است و پیشرفتهای چشمگیری در این باره به وجود آمده است.در این راستا نسل اول تا چهارم موبایل به وجود آمده است.نسل دوم GSM (Global System for Mobile communications) محبوبترین سیستم تلفن موبایل در جهان است چکیده کامل

با توجه به افزایش ارتباطات ، شبکه های موبایل روز به روز در حال گسترش است و پیشرفتهای چشمگیری در این باره به وجود آمده است.در این راستا نسل اول تا چهارم موبایل به وجود آمده است.نسل دوم GSM (Global System for Mobile communications) محبوبترین سیستم تلفن موبایل در جهان است و بر اساس آخرین اخبار منتشره ،هم اکنون بیش از 500میلیون نفر در بیش از 150 کشور از این سیستم استفاده میکنند.در کشور ما نیزشبکه مورد استفاده GSM است.از طرف دیگر از آنجا که سیستم موبایل از واسط هوایی برای انتقال استفاده می کند و واسط هوایی بسیار آسیب پذیر است، امنیت شبکه اهمیت دو چندانی می یابد. . شبکه پیرامونی BTS به عنوان یک محیط تحت کنترل مورد بررسی قرار می‌گیرد، چرا که دستیابی به این بخش از شبکه به وسیله ارایه کننده‌های خدمات، کنترل می‌شود. شبکه دستیابی ( اتصال دهنده ME/MS به BTS) تنها شبکه‌ای است که یک محیط عملیاتی، مخرب محسوب می‌شود. بنابراین هدف، ایجاد امنیت در این بخش از شبکه GSM است. پرونده مقاله

دسترسی آزاد مقاله

2 - Micro Wire Electrical Discharge Machining of MEMS Structures with Optimized Dimensional Deviation
Mohammad Tahmasebipour Younes Tahmasebipour Ali Vafaie

Metal-based microelectromechanical systems are widely used in applications such as micro-energy harvesters, micro-heat exchangers and micro-electromagnetic that require high strength and flexibility. In the fabrication of such systems, micro wire electrical discharge ma چکیده کامل

Metal-based microelectromechanical systems are widely used in applications such as micro-energy harvesters, micro-heat exchangers and micro-electromagnetic that require high strength and flexibility. In the fabrication of such systems, micro wire electrical discharge machining (MicroWEDM) is majorly used. This paper studies the effect of the MicroWEDM process parameters on the dimensional deviation of machined MEMS structures including microcantilevers and micro-beams using the Taguchi method. Using optimal levels of the parameters including pulse duration (0.8 µs), cutting speed (8.4 mm/min), voltage (17 V) and wire tension (0.5 kg), the dimensional deviation is reduced about 8.65 times compared with the average of experiments results. The order of effect importance of the process parameters on the dimensional deviation of microstructures obtained by the ANOVA analysis of S/N ratios is as follows: pulse duration, wire tension, process voltage and cutting speed. Dimensional deviation of the micro-features was reduced to 1 μm using the optimal levels of the process parameters. پرونده مقاله

دسترسی آزاد مقاله

3 - Micro Electropolishing of the MEMS Metallic Structures Fabricated by the Micro WEDM Process
Mohammad Tahmasebipour Younes Tahmasebipour Mahya Boujari Aliabadi Shadi Ebrahimi

10.30486/admt.2022.1928592.1277

In this study, the micro electro-polishing method was employed to improve the surface quality of microbeams machined by the micro WEDM method and to remove the recast layer. This approach changes the dimensions of the microbeams, as a result of the electrochemical corro چکیده کامل

In this study, the micro electro-polishing method was employed to improve the surface quality of microbeams machined by the micro WEDM method and to remove the recast layer. This approach changes the dimensions of the microbeams, as a result of the electrochemical corrosion, in addition to the elimination of the recast layer. To diminish the impact of this process on the dimensional deviation of the fabricated microbeams, the influence of the micro electro-polishing process parameters such as voltage, duration, cathode diameter, and electrolyte composition on the dimensional deviation of microbeams was studied using the Taguchi method. The optimum values of process parameters were determined by the S/N ratios analysis, and the order of parameters importance was determined through analysis of variance of the S/N ratios. It was found that the optimal levels of the process parameters are voltage of 2 V, process duration of 20 s, cathode diameter of 50 mm, and electrolyte composition of 25-5-40 ml (sulfuric-phosphoric-water) within the range of experiments. By using the optimum values of the parameters, the dimensional deviations were found to be 5.23 times lower compared to the average of the results. The importance of process parameters was found to follow this order: electropolishing duration, electrolyte composition, cathode diameter, and process voltage. پرونده مقاله

دسترسی آزاد مقاله

4 - A New Model of Pull-in Voltage for MEMS Variable Capacitive with Fully-clamped Diaphragm
Bahram Azizollah Ganji Sara Gholinezhad Shafagh

In this paper a new model of Pull-in Voltage for MEMS capacitor with fully clamped diaphragm is presented. This model not only makes it possible to calculate the exact value of pull-in voltage in a capacitor but also provides the ability to detect the accurate deflectio چکیده کامل

In this paper a new model of Pull-in Voltage for MEMS capacitor with fully clamped diaphragm is presented. This model not only makes it possible to calculate the exact value of pull-in voltage in a capacitor but also provides the ability to detect the accurate deflection of a fully clamped diaphragm. By introducing this model, the precise value of pull-in voltage at the border, between stable and un-stable state, can be calculated. As an advantage of this new achievement, it is exhibited that the all theoretical equations are fully compatible with simulation results using finite element analysis (FEA). پرونده مقاله

دسترسی آزاد مقاله

5 - Design and Simulation of a Dual-Mode Resonant Temperature sensor Based on MEMS Technology
Elham Farzanegan Farshad Babazadeh

In this paper, a dual-mode (DM) micromechanical elliptical ring resonator for use in temperature sensing is reported. The proposed resonator is made of single crystal silicon and works based on beat frequency (fb). In the designed sensor, temperature coefficient of beat چکیده کامل

In this paper, a dual-mode (DM) micromechanical elliptical ring resonator for use in temperature sensing is reported. The proposed resonator is made of single crystal silicon and works based on beat frequency (fb). In the designed sensor, temperature coefficient of beat frequency (TCfb) will be increased significantly by minimizing the fb and provides better temperature sensitivity. This proposed device was designed and simulated by COMSOL Multyphysics software. By engineering the device geometry, we introduce two adjacent resonant frequencies which produce very small fb in the range of 2 kHz. The device shows TCf1 of about 44 ppm/ºC and TCf2 of 5 ppm/ºC. Combination of small fb and large ΔTCf, present temperature coefficient of beat frequency (TCfb) about 112000 ppm/ºC which has approximately 75improvement in TCfb compared to previous demonstrated DM resonators. پرونده مقاله

دسترسی آزاد مقاله

6 - Characterization of the Viscoelastic Q-Factor of Electrically Actuated Rectangular Micro-Plates
E Keykha H Rahmani H Moeinkhah M Salehi Kolahi

10.22034/jsm.2021.1917950.1663

Regarding the necessity of designing high Q-resonators in micro electromechanical systems, this paper investigates the viscoelastic behavior of a rectangular micro-plate subjected to electrical actuation. Equations governing the vibrations of the homogeneous plate were چکیده کامل

Regarding the necessity of designing high Q-resonators in micro electromechanical systems, this paper investigates the viscoelastic behavior of a rectangular micro-plate subjected to electrical actuation. Equations governing the vibrations of the homogeneous plate were obtained on the basis of classical plate theory (Kirchhoff's model). The Kelvin–Voigt model was also employed to consider the viscoelastic properties. The Galerkin decomposition method was used for decomposition of the governing differential equations. Additionally, the effects of various parameters were investigated on the Q-factor. Furthermore, a Finite Element simulation is carried out using COMSOL Multiphysics. The verification of the proposed model was conducted by comparing the obtained results with those from previous studies which revealed the validity of the proposed approach and the accuracy of the assumptions made The suggested design approach proposed in this this study is expected to design high Q-factor micro resonators and may be used to improve the performance of many MEMS devices. پرونده مقاله

دسترسی آزاد مقاله

7 - Mechanical Behavior of an Electrostatically-Actuated Microbeam under Mechanical Shock
M Fathalilou A Motallebi H Yagubizade Gh Rezazadeh K Shirazi Y Alizadeh

In this paper static and dynamic responses of a fixed-fixed microbeam to electrostatic force and mechanical shock for different cases have been studied. The governing equations whose solution holds the answer to all our questions about the mechanical behavior is the non چکیده کامل

In this paper static and dynamic responses of a fixed-fixed microbeam to electrostatic force and mechanical shock for different cases have been studied. The governing equations whose solution holds the answer to all our questions about the mechanical behavior is the nonlinear elasto-electrostatic equations. Due to the nonlinearity and complexity of the derived equations analytical solution are not generally available; therefore, the obtained differential equations have been solved by using of a step by step linearization method (SSLM) and a Galerkin based reduced order model. The pull-in voltage of the structure and the effect of shock forces on the mechanical behavior of undeflected and electrostatically deflected microbeam have been investigated. The proposed models capture the other design parameters such as intrinsic residual stress from fabrication processes and the nonlinear stiffening or stretching stress due to beam deflection. پرونده مقاله

دسترسی آزاد مقاله

8 - Effect of Electric Potential Distribution on Electromechanical Behavior of a Piezoelectrically Sandwiched Micro-Beam
A Shah-Mohammadi-Azar G Rezazadeh R Shabani

The paper deals with the mechanical behavior of a micro-beam bonded with two piezoelectric layers. The micro-beam is suspended over a fixed substrate and undergoes the both piezoelectric and electrostatic actuation. The piezoelectric layers are poled through the thickne چکیده کامل

The paper deals with the mechanical behavior of a micro-beam bonded with two piezoelectric layers. The micro-beam is suspended over a fixed substrate and undergoes the both piezoelectric and electrostatic actuation. The piezoelectric layers are poled through the thickness and equipped with surface electrodes. The equation governing the micro-beam deflection under electrostatic pressure is derived according to Euler-Bernoulli beam theory and considering the voltage applied to the piezoelectric layers and Maxwell’s equations for the two dimensional electric potential distribution. The obtained nonlinear equation solved by step by step linearization method and Galerkin weighted residual method. The effects of the electric potential distribution and the ratio of the piezoelectric layer thickness respect to the elastic layer thickness on the mechanical behavior of the micro-beam are investigated. The obtained results are compared with the results of a model in which electric potential distribution is not considered. پرونده مقاله

دسترسی آزاد مقاله

9 - Dynamic Characteristics and Vibrational Response of a Capacitive Micro-Phase Shifter
M Fathalilou M Sadeghi S Afrang G Rezazadeh

The objective of this paper is to control the phase shifting by applying a bias DC voltage and changing the mechanical characteristics in electrostatically-actuated micro-beams. This problem can be more useful in the design of micro-phase shifters, which has not general چکیده کامل

The objective of this paper is to control the phase shifting by applying a bias DC voltage and changing the mechanical characteristics in electrostatically-actuated micro-beams. This problem can be more useful in the design of micro-phase shifters, which has not generally been investigated their mechanical behavior. By presenting a mathematical modeling, Galerkin-based step by step linearization method (SSLM) and Galerkin-based reduced order model have been used to solve the governing static and dynamic equations, respectively. The equilibrium positions or fixed pints of the system have been determined and the calculated static and dynamic pull-in parameters have been validated by previous experimental and theoretical results and a good agreement has been achieved. The frequency response of the system has been studied and illustrated that changing applied bias DC voltage affects the resonance frequency and maximum amplitude of the system vibrations. Then, phase diagram of the system for various damping ratio and excitation frequencies has been gained. It has been shown that by changing the bias DC voltage applied on the electrostatically-actuated micro-beam, which can be used as a varactor in phase shifter circuit, the stiffness of the micro-beam changes and consequently the phase shifting can be controlled. Finally, effect of the geometrical and mechanical properties of the micro-beam on the value of the phase shifting has been studied. پرونده مقاله

دسترسی آزاد مقاله

10 - Study on the Pull-In Instability of Gold Micro-Switches Using Variable Length Scale Parameter
M Fathalilou M Sadeghi G Rezazadeh M Jalilpour A Naghilou S Ahouighazvin

In this paper, the size dependent behavior of the gold micro-switches has been studied. This behavior becomes noticeable for a structure when the characteristic size such as thickness or diameter is close to its internal length-scale parameter. The size dependent effect چکیده کامل

In this paper, the size dependent behavior of the gold micro-switches has been studied. This behavior becomes noticeable for a structure when the characteristic size such as thickness or diameter is close to its internal length-scale parameter. The size dependent effect is insignificant for the high ratio of the characteristic size to the length-scale parameter, which is the case of the silicon base micro-beams. On the other hand, in some types of micro-beams like gold base, the size dependent effect cannot be overlooked. In such cases, ignoring this behavior in modeling will lead to incorrect results. Some previous researchers have applied classic beam theory on their models and imposed a considerable hypothetical value of residual stress to match their theoretical results with the experimental ones. In this study, by obtaining the equilibrium positions or fixed points of the gold micro-beam, a considerable difference between the obtained fixed points using classic beam theory and modified couple stress theory has been shown. In addition, it has been shown that the calculated pull-in voltages using modified couple stress theory are much closer to the experimental results than those obtained by classic beam theory. Finally, it has been shown that considering a unique value of length scale parameter, especially for the smallest values of the beam thicknesses, may leads to inaccurate results and variable length scale parameter should be considered. پرونده مقاله

دسترسی آزاد مقاله

11 - Effects of the Residual Stress and Bias Voltage on the Phase Diagram and Frequency Response of a Capacitive Micro-Structure
S Ahouighazvin M Mohamadifar P Mahmoudi

In this paper, static and dynamic behavior of a varactor of a micro-phase shifter under DC, step DC and AC voltages and effects of the residual stress on the phase diagram have been studied. By presenting a mathematical modeling, Galerkin-based step by step linearizatio چکیده کامل

In this paper, static and dynamic behavior of a varactor of a micro-phase shifter under DC, step DC and AC voltages and effects of the residual stress on the phase diagram have been studied. By presenting a mathematical modeling, Galerkin-based step by step linearization method (SSLM) and Galerkin-based reduced order model have been used to solve the governing static and dynamic equations, respectively. The calculated static and dynamic pull-in voltages have been validated by previous experimental and theoretical results and a good agreement has been achieved. Then the frequency response and phase diagram of the system have been studied. It has been shown that increasing the bias voltage shifts down the phase diagram and left the frequency response. Also increasing the damping ratio shifts up the phase diagram. Finally, the effect of residual stress on the phase diagram has been studied. پرونده مقاله

دسترسی آزاد مقاله

12 - Damping Ratio in Micro-Beam Resonators Based on Magneto-Thermo-Elasticity
A Khanchehgardan G Rezazadeh A Amiri

This paper investigates damping ratio in micro-beam resonators based on magneto-thermo-elasticity. A unique aspect of the present study is the effect of permanent magnetic field on the stiffness and thermo-elastic damping of the micro resonators. In our modeling the the چکیده کامل

This paper investigates damping ratio in micro-beam resonators based on magneto-thermo-elasticity. A unique aspect of the present study is the effect of permanent magnetic field on the stiffness and thermo-elastic damping of the micro resonators. In our modeling the theory of thermo-elasticity with interacting of an externally applied permanent magnetic field is taken into account. Combined theoretical and numerical studies investigate the permanent magnetic field effect on the damping ratio in clamped-clamped and cantilever micro-beams. Furthermore, the influence of the magnetic field intensity on the frequency of the micro-beams with thermo-elastic damping effect is evaluated. Such evaluations are used to determine the influence of magnetic field on the vibration amplitude of the resonators. The meaningful conclusion is that the magnetic field increases the equivalent stiffness and thermo-elastic damping and consequently the energy consumption of the resonators. پرونده مقاله

دسترسی آزاد مقاله

13 - Study Of Thermoelastic Damping in an Electrostatically Deflected Circular Micro-Plate Using Hyperbolic Heat Conduction Model
G Rezazadeh S Tayefeh-rezaei A Saeedi Vahdat V Nasirzadeh

Thermoelastic damping (TED) in a circular micro-plate resonator subjected to an electrostatic pressure is studied. The coupled thermo-elastic equations of a capacitive circular micro plate are derived considering hyperbolic heat conduction model and solved by applying G چکیده کامل

Thermoelastic damping (TED) in a circular micro-plate resonator subjected to an electrostatic pressure is studied. The coupled thermo-elastic equations of a capacitive circular micro plate are derived considering hyperbolic heat conduction model and solved by applying Galerkin discretization method. Applying complex-frequency approach to the coupled thermo-elastic equations, TED is obtained for different ambient temperatures. Effects of the geometrical parameters on TED and the critical thickness are investigated. Furthermore, the effect of applied bias DC voltage on TED for an electrostatically deflected micro-plate is also investigated. پرونده مقاله

دسترسی آزاد مقاله

14 - Effect of Temperature Changes on Dynamic Pull-in Phenomenon in a Functionally Graded Capacitive Micro-beam
B Mohammadi-Alasti G Rezazadeh M Abbasgholipour

In this paper, dynamic behavior of a functionally graded cantilever micro-beam and its pull-in instability, subjected to simultaneous effects of a thermal moment and nonlinear electrostatic pressure, has been studied. It has been assumed that the top surface is made of چکیده کامل

In this paper, dynamic behavior of a functionally graded cantilever micro-beam and its pull-in instability, subjected to simultaneous effects of a thermal moment and nonlinear electrostatic pressure, has been studied. It has been assumed that the top surface is made of pure metal and the bottom surface from a metal–ceramic mixture. The ceramic constituent percent of the bottom surface ranges from 0% to 100%. Along with the Volume Fractional Rule of material, an exponential function has been applied to represent the continuous gradation of the material properties through the micro-beam thickness. Attentions being paid to the ceramic constituent percent of the bottom surface, five different types of FGM micro-beams have been studied. Nonlinear integro-differential thermo-electro-mechanical equation based on Euler–Bernoulli beam theory has been derived. The governing equation in the static case has been solved using Step-by-Step Linearization Method and Finite Difference Method. Fixed points or equilibrium positions and singular points of the FGM micro-beam have been determined and shown in the state control space. In order to study stability of the fixed points, beam motion trajectories have been drawn, with different initial conditions, in the phase plane. In order to find the response of the micro-beam to a step DC voltage, the nonlinear equation of motion has been solved using Galerkin-based reduced-order model and time histories and phase portrait for different applied voltages and various primal temperatures have been illustrated. The effects of temperature change and electrostatic pressure on the deflection and stability of FGM micro-beams having various amounts of the ceramic constituent have been studied . پرونده مقاله

دسترسی آزاد مقاله

15 - Frequency Response Analysis of a Capacitive Micro-beam Resonator Considering Residual and Axial Stresses and Temperature Changes Effects
S Valilou M Jalilpour

This paper presents a study on the frequency response of a capacitive micro-beam resonator under various applied stresses. The governing equation whose solution holds the answer to all our questions about the mechanical behavior is the nonlinear electrostatic equation. چکیده کامل

This paper presents a study on the frequency response of a capacitive micro-beam resonator under various applied stresses. The governing equation whose solution holds the answer to all our questions about the mechanical behavior is the nonlinear electrostatic equation. Due to the nonlinearity and complexity of the derived equation analytical solution are not generally available; therefore, the obtained differential equation has been solved by using a step by step linearization scheme and a Galerkin based reduced order model. The obtained static pull-in voltages have been validated by previous reports and a good agreement has been achieved. The dynamic behavior of the beam under residual, axial and thermal stresses has been investigated. It has been shown that applying the positive residual stress and negative temperature changes shifts right the frequency response and decrease the vibration amplitude and vice versa. Also, it has been shown that applying the bias DC voltage beside the exciting AC voltage decreases the stiffness of the system and so, shifts left the frequency response and increases the vibration amplitude. پرونده مقاله

دسترسی آزاد مقاله

16 - Crack Influences on the Static and Dynamic Characteristic of a Micro-Beam Subjected to Electro Statically Loading
A.R Shahani G Rezazadeh A Rahmani

In the present work the pull-in voltage of a micro cracked cantilever beam subjected to nonlinear electrostatic pressure was studied. Two mathematical models were employed for modeling the problem: a lumped mass model and a classical beam model. The effect of crack in t چکیده کامل

In the present work the pull-in voltage of a micro cracked cantilever beam subjected to nonlinear electrostatic pressure was studied. Two mathematical models were employed for modeling the problem: a lumped mass model and a classical beam model. The effect of crack in the lumped mass model is the reduction of the effective stiffness of the beam and in the beam model; the crack is modeled as a massless rotational spring the compliance of which is related to the crack depth. Using these two models the pull-in voltage is extracted in the static and dynamic cases. Stability analysis is also accomplished. It has been observed that the pull-in voltage decreases as the crack depth increases and also when the crack approaches the clamped support of the beam. The finding of this research can further be used as a non-destructive test procedure for detecting cracks in micro-beams. پرونده مقاله

دسترسی آزاد مقاله

17 - On the Stability of an Electrostatically-Actuated Functionally Graded Magneto-Electro-Elastic Micro-Beams Under Magneto-Electric Conditions
A Amiri G Rezazadeh R Shabani A Khanchehgardan

In this paper, the stability of a functionally graded magneto-electro-elastic (FG-MEE) micro-beam under actuation of electrostatic pressure is studied. For this purpose Euler-Bernoulli beam theory and constitutive relations for magneto-electro-elastic (MEE) materials ha چکیده کامل

In this paper, the stability of a functionally graded magneto-electro-elastic (FG-MEE) micro-beam under actuation of electrostatic pressure is studied. For this purpose Euler-Bernoulli beam theory and constitutive relations for magneto-electro-elastic (MEE) materials have been used. We have supposed that material properties vary exponentially along the thickness direction of the micro-beam. Governing motion equations of the micro-beam are derived by using of Hamilton’s principle. Maxwell’s equation and magneto-electric boundary conditions are used in order to determine and formulate magnetic and electric potentials distribution along the thickness direction of the micro-beam. By using of magneto-electric potential distribution, effective axial forces induced by external magneto-electric potential are formulated and then the governing motion equation of the micro-beam under electrostatic actuation is obtained. A Galerkin-based step by step linearization method (SSLM) has been used for static analysis. For dynamic analysis, the Galerkin reduced order model has been used. Static pull-in instability for 5 types of MEE micro-beam with different gradient indexes has been investigated. Furthermore, the effects of external magneto-electric potential on the static and dynamic stability of the micro-beam are discussed in detail. پرونده مقاله

دسترسی آزاد مقاله

18 - A Numerical Investigation the Effects of the Voltage on the Displacement and Stress of Copper-based Ionic Polymer-Metal Composites
Hamid Soleimanimehr Amin Nasrollah

Ionic polymer material composites (IPMCs) are a group of polymeric material which deform by applying voltage and the movement of cations of polymer; it should be mentioned that the finite element method using electromechanics equations can be used to analyze these types چکیده کامل

Ionic polymer material composites (IPMCs) are a group of polymeric material which deform by applying voltage and the movement of cations of polymer; it should be mentioned that the finite element method using electromechanics equations can be used to analyze these types of problem and measure the deformation. This phenomenon can causes bending and internal stress. This research, it is tried to investigate the displacement and stress of IPMC by modeling and finite element method analysis. Firstly, a 2D IPMC is designed; then the materials are applied which are cooper for the electrodes and Nafion for the polymeric core. After applying boundary conditions and meshing, the results have been analyzed by the finite element method. It is found that the relation between voltage and its effect on the bending displacement of IPMC is direct. The conclusions include the maximum displacement of IPMC membrane under the voltage of 5V is 0.42 mm and the maximum Von Mises stress on the electrode is gained 3.29×1016 (N/m2). پرونده مقاله

دسترسی آزاد مقاله

19 - Simulation of a Microgripper with Electrothermal Actuator Using COMSOL Software Based on the Finite Element Method
Amin Rouhani Esfahani Mojtaba Kolahdouzan Mehran Moradi

Micro-electro-mechanical systems (MEMs) are Combination of electrical and mechanical components in Micron dimensions. In recent years, holding, actuating methods and handling of MEMs components such as microgripper, microsensors and etc. have been deeply studied. Microg چکیده کامل

Micro-electro-mechanical systems (MEMs) are Combination of electrical and mechanical components in Micron dimensions. In recent years, holding, actuating methods and handling of MEMs components such as microgripper, microsensors and etc. have been deeply studied. Microgrippers for handling, positioning and assembling of micro components are very useful so that for clamping need actuation created using electrostatic, electrothermal, and electromagnetic actuators. In this paper, a new design of an electrothermal microgripper with U-shape actuators for holding and carrying a wide range of parts at the same time, For voltages corresponding between 1 to 10 volts, have been fabricated. The microgripper is made of silicone with thickness of 25 microns, and pieces between 460 to 480 microns that can hold it. The behavior of the microgripper in Multi physics powerful finite element software (COMSOL) was evaluated and the displacements of arms hold and heat generations have been simulated. پرونده مقاله

دسترسی آزاد مقاله

20 - Fractional Order Control of Micro Electro-Mechanical Systems
Mohammad Goodarzi

This paper addresses the problem of the fractional sliding mode control (FSMC) for a MEMS optical switch. The proposed scheme utilizes a fractional sliding surface to describe dynamic behavior of the system in the sliding mode stage. After a comparison with the classica چکیده کامل

This paper addresses the problem of the fractional sliding mode control (FSMC) for a MEMS optical switch. The proposed scheme utilizes a fractional sliding surface to describe dynamic behavior of the system in the sliding mode stage. After a comparison with the classical integer-order counterpart, it is seen that the control system with the proposed sliding surface displays better transient performance. The claims are justified through a set of simulations and the results obtained are found promising. Overall, the contribution of this paper is to demonstrate that the response of the system under control is significantly better for the fractional-order differentiation exploited in the sliding surface design stage than that for the classical integer-order one, under the same conditions. پرونده مقاله

دسترسی آزاد مقاله

21 - Robust Lyapunov-based Control of MEMS Optical Switches
Mohammad Goodarzi

In this paper, a robust PID control scheme is proposed for Micro-Electro-Mechanical-Systems (MEMS) optical switches. The proposed approach is designed in a way which solves two challenging and important problems. The first one is successful reference tracking and the se چکیده کامل

In this paper, a robust PID control scheme is proposed for Micro-Electro-Mechanical-Systems (MEMS) optical switches. The proposed approach is designed in a way which solves two challenging and important problems. The first one is successful reference tracking and the second is mitigating the system nonlinearities. The overall system composed of nonlinear MEMS dynamics and the PID controller is proven to be uniformly-ultimately bounded (UUB) stable in agreement with Lyapunov’s direct method in any finite region of the state space. Since the unmodeled but bounded dynamics of the system is systematically encapsulated in the system model, the only influence that this imposes on the stability is the respective bounds on the controller gains. The controller design strategy is simple and practicable with low computation burden which makes it easy to apply for control of MEMS optical switch. It also forms a constructive and conservative algorithm for suitable choice of gains in PID controller. The effectiveness of the proposed control law is verified through simulations in MATLAB/SIMULINK. It is shown that the proposed control law ensures robust stability and performance despite the modeling uncertainties. پرونده مقاله

دسترسی آزاد مقاله

22 - بررسی تاثیر ضخامت و فشار در دیافراگم های میکرو الکترو مکانیکی در میزان جابجائی در کاربردهای پزشکی
نازلی زرگرپورفردین

در این مقاله، تاثیر پارامترهای طراحی در دیافراگم بر روی حساسیت میکروفن به منظور استفاده در کاربردهای پزشکی قابل کاشت ارائه گردیده است. پارامترهای متفاوتی از دیافراگم همچون شکل، ابعاد، ضخامت و فشارهای اعمالی مختلف بر روی دیافراگم در نظر گرفته شده‌است. تاثیر تغییرات در ای چکیده کامل

در این مقاله، تاثیر پارامترهای طراحی در دیافراگم بر روی حساسیت میکروفن به منظور استفاده در کاربردهای پزشکی قابل کاشت ارائه گردیده است. پارامترهای متفاوتی از دیافراگم همچون شکل، ابعاد، ضخامت و فشارهای اعمالی مختلف بر روی دیافراگم در نظر گرفته شده‌است. تاثیر تغییرات در این پارامترها بر روی میزان جابجائی و استرس در انواع شکل دیافراگم ها‌ مورد بحث و بررسی واقع شده است. به منظور طراحی بهینه، انواع شکل دیافراگم های پیشنهادی، از جهت پارامترهای در نظر گرفته شده در نرم افزار COMSOL شبیه سازی و آنالیز شده اند. با توجه به پارامترهای مورد بررسی، انواع اشکال دیافراگم مربعی، مستطیلی و بیضوی شکل با توجه به شرایط در نظر گرفته شده، دارای میانگین جابجائی مرکزی در محدوده فرکانس شنوائی انسان 20Hz-20KHz به ترتیب nm2. 6 ، nm 5. 5 و nm 130می باشد. نتایج حاصل از شبیه سازی ها بدین صورت می باشد که دیافراگم بیضوی شکل نسبت به اشکال دیگر مورد بررسی در این مقاله، برای کاربردهای پزشکی و امکان کاشته شدن، دارای کارائی بهینه و مطلوبی می باشد. به علاوه، ماده ی پیزوالکتریک مورد استفاده در طراحی دیافراگم PZT است. پرونده مقاله

دسترسی آزاد مقاله

23 - میکروفن خازنی با اندازه کوچک و حساسیت بالا با به کار گیری دیافراگم دایروی با مرکز ثابت
نسترن نادمی جواد کرمدل

در این مقاله، یک میکروفن خازنیMEMS جدید تک تراشه بر روی ویفر سیلیکونی با کمینه کردن اندازه و کاهش استحکام مکانیکی با استفاده از دیافراگم دایروی با مرکز ثابت پیشنهاد شده است. در میکروفن پیشنهادی دیافراگم شامل تعدادی حفره می‌باشد که موجب عبور هوا در شکاف مابین صفحه پشتی و چکیده کامل

در این مقاله، یک میکروفن خازنیMEMS جدید تک تراشه بر روی ویفر سیلیکونی با کمینه کردن اندازه و کاهش استحکام مکانیکی با استفاده از دیافراگم دایروی با مرکز ثابت پیشنهاد شده است. در میکروفن پیشنهادی دیافراگم شامل تعدادی حفره می‌باشد که موجب عبور هوا در شکاف مابین صفحه پشتی و دیافراگم می‌شود و به این ترتیب میرائی مربوط به صدا را در میکروفن کاهش می‌دهد. ‌تازگی این روش، ایجاد میکروفن دایروی با مرکز ثابت می‌باشد که قطر دیافراگم کمتر از میکروفن خازنی مرسوم به دست می‌آید. ابتدا تحلیل مکانیکی روی دیافراگم میکروفن انجام می‌گیرد تا ولتاژ کششی به دست آید. ولتاژ کششی میکروفن دایروی پیشنهادی 14 ولت می‌باشد. با توجه به ولتاژ کششی بدست آمده٬ ولتاژ بایاس به میکروفن اعمال شده و پارامترهای مختلف مانند ظرفیت خازنی و حساسیت اندازه‌گیری شد. با توجه به نتایج شبیه‌سازی کامسول (COMSOL)، میکروفن پیشنهادی با دیافراگم به قطر 400 میکرومتر و ضخامت 5/1 میکرومتر، حساسیت‌ 23- دسی‌بل را نشان داد. در مقایسه با کارهای قبلی، میکروفن پیشنهادی با ولتاژ تغذیه کمتر عملکرد فرکانسی بهتر و حساسیت بیشتری را برای سنس نمودن صدا عرضه می‌کند پرونده مقاله

دسترسی آزاد مقاله

24 - Design and Nonlinear Analysis of a Novel MEMS-Based Resonator for Biomedical Applications
Farbod Setoudeh Mohsen Ghadami

10.30495/ijsee.2022.1951821.1172

Complementary metal oxide semiconductor (CMOS) based microelectromechanical systems (MEMS) resonators are the main component of modern integrated systems that are designed and fabricated using CMOS composite layers. The design of these resonators, which are actuated ele چکیده کامل

Complementary metal oxide semiconductor (CMOS) based microelectromechanical systems (MEMS) resonators are the main component of modern integrated systems that are designed and fabricated using CMOS composite layers. The design of these resonators, which are actuated electrostatically, is strongly dependent on the ambient temperature and the used materials. Important factors, such as structural features, actuator type, and the used materials should be considered in the design of micro resonators because they strongly affect the quality factor, power consumption and operating frequency of these devices. However, in designing micro resonators, electrostatic actuators are preferred over other actuator types due to their lower manufacturing cost, lower losses, and higher controllability. In this paper, first, some micro resonators are designed and their structures are then investigated. The micro resonators are mechanically analyzed to optimize their dimensions. A bias voltage of 0.1 V is applied to the micro resonators to investigate their feasibility for implantable biomedical applications. The switching time for a Zinc (Zn) movable plate is equal to 0.5 µs. In this paper, the role of device dimensions, Young’s modulus, switching time, material type, bridge displacement, and voltage (which is an important challenge in electrostatic resonators since it is usually high), as well as the effects of temperature on displacement are investigated. پرونده مقاله

دسترسی آزاد مقاله

25 - تاثیر قرار دادن لایه نازک سیلیکون در زیر غشای دی‌الکتریک بر روی عملکرد یک میکروهیتر
فاطمه سمایی فر احمد عفیفی حسن عبداللهی

با توسعه ریزفناوری میکروماشین کاری و میکروالکترونیک، میکروهیترها کاربردهای زیادی در میکروحسگرها پیدا کرده اند. یکنواختی توزیع دما یکی از عوامل تاثیرگذار در افزایش حساسیت و دقت یک حسگر گازی است که در آن هیتر استفاده شده است. در این مقاله روش قرار دادن لایه نازک سیلیکون د چکیده کامل

با توسعه ریزفناوری میکروماشین کاری و میکروالکترونیک، میکروهیترها کاربردهای زیادی در میکروحسگرها پیدا کرده اند. یکنواختی توزیع دما یکی از عوامل تاثیرگذار در افزایش حساسیت و دقت یک حسگر گازی است که در آن هیتر استفاده شده است. در این مقاله روش قرار دادن لایه نازک سیلیکون در زیر غشای دی الکتریک به منظور بهبود یکنواختی گرما در میکروهیتر، مورد بررسی قرار گرفته است. دو میکروهیتر پلاتینی با ساختار غشای معلق بر روی بستر سیلیکون و بر پایه فناوری میکروماشین کاری حجمی طراحی، ساخته و مشخصه یابی شده اند. در میکروهیتر اول از لایه نازک سیلیکون به ضخامت µm10 در زیر غشای دی الکتریک استفاده شده است در حالیکه میکروهیتر دوم بدون این لایه ساخته شده است. نتایج شبیه سازی نشان می دهد که با قرار دادن لایه نازک سیلیکون، یکنواختی توزیع دما و استحکام مکانیکی بهبود می یابد درحالیکه توان مصرفی و پاسخ زمانی افزایش می یابد. هم چنین نتایج تجربی به نتایج حاصل از شبیه سازی بسیار نزدیک است و نشان می دهد که میکروهیتر با لایه نازک سیلیکون به ضخامت µm10 برای رسیدن به دمای oC500 دارای توان مصرفی و پاسخ زمانی mW50 و ms23/4 به ترتیب می باشد ولی میکروهیتر ساخته شده بدون این لایه، برای رسیدن به این دما دارای توان مصرفی و پاسخ زمانی mW13 و ms4/2 است. پرونده مقاله

فهرست مقالات MEMS

سکوی نشر دانش

پیوندهای سایت

مراکز مرتبط

پشتیبانی

صفحات رسمی