The Experts below are selected from a list of 1034748 Experts worldwide ranked by ideXlab platform
M T Ahmadian - One of the best experts on this subject based on the ideXlab platform.
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static pull in analysis of microcantilevers based on the modified couple stress theory
Sensors and Actuators A-physical, 2011Co-Authors: M Rahaeifard, M H Kahrobaiyan, M Asghari, M T AhmadianAbstract:Abstract This paper investigates the deflection and static Pull-in Voltage of microcantilevers based on the modified couple stress theory, a non-classic continuum theory capable to predict the size effects for structures in micron and sub-micron scales. It is shown that the couple stress theory can remove the gap between the experimental observations and the classical theory based simulations for the static Pull-in Voltage.
P.j. George - One of the best experts on this subject based on the ideXlab platform.
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A novel method to predict the effect of static charges on the Pull-in Voltage and touch-point pressure of the capacitive transducer with square diaphragm
International Journal of Advances in Engineering Sciences and Applied Mathematics, 2010Co-Authors: Anurekha Sharma, P.j. GeorgeAbstract:Microelectromechanical systems (MEMS) use silicon based dielectric films such as SiO2 and Si3N4 for providing insulation. In capacitive transducers, these layers are used as insulation layers for capacitive actuators to prevent short-circuiting of electrodes by contact of electrodes and in case of touchmode capacitive pressure sensors (TMCPS), the dielectric layer provides for overload protection and provides for operation in the pressure ranges in which the diaphragm comes in contact with dielectric. The pressure at which diaphragm just touches the dielectric is referred to as touch-point pressure. In case of actuator, Pull-in Voltage is a critical parameter that decides the onset of instability in operation of the device. Silicon based dielectric thin films have the tendency to store or trap static charges, the presence of which alters the ideal behaviour of dielectrics. These trapped static charges introduced due fabrication processes; handling and operation affect the operation of capacitive transducers by influencing the Pull-in Voltage and by affecting the touch-point pressure. This paper presents a novel methodology, which predicts the Pull-in Voltage and touch-point pressure in presence of the static charges in a dielectric. The method proposed is less complex and less time consuming. Closed form expressions have been derived for Pull-in Voltage, touch-point pressure and critical displacement in presence of static charges. The results are compared with those obtained by experiment.
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A simple method for calculation of the Pull-in Voltage and touch-point pressure for the small deflection of square diaphragm in MEMS
Sensors and Actuators A-physical, 2008Co-Authors: Anurekha Sharma, P.j. GeorgeAbstract:There are a number of MEMS structures that make use of diaphragms. The deformation of the diaphragm for the purpose of actuation and transduction can be brought about by application of Voltage and/or pressure or any other mechanical excitation like acceleration, force, etc. The amount of deformation can be measured by changes in the capacitance between the diaphragm and the fixed electrode. The gap between the electrodes can be an air gap or can have an intervening layer of the dielectric on the fixed electrode along with the air gap. The Pull-in Voltage and touch-point pressure along with the structural and material properties are critical parameters that decide the behavior of the actuator/transducer. This paper presents a simple methodology, which is capable of representing small deflection of diaphragm with pressure, and/or applied Voltage. The method proposed is less complex and less time consuming in comparison with FEM tools. Closed form expressions have been derived for Pull-in Voltage with/without dielectric between the two electrodes and critical distance for Pull-in. The closed form expressions for touch-point pressure have also been derived. The results are compared with those obtained by simulation as well as experiment.
M Rahaeifard - One of the best experts on this subject based on the ideXlab platform.
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static pull in analysis of microcantilevers based on the modified couple stress theory
Sensors and Actuators A-physical, 2011Co-Authors: M Rahaeifard, M H Kahrobaiyan, M Asghari, M T AhmadianAbstract:Abstract This paper investigates the deflection and static Pull-in Voltage of microcantilevers based on the modified couple stress theory, a non-classic continuum theory capable to predict the size effects for structures in micron and sub-micron scales. It is shown that the couple stress theory can remove the gap between the experimental observations and the classical theory based simulations for the static Pull-in Voltage.
Koushik Guha - One of the best experts on this subject based on the ideXlab platform.
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Design, simulation and analysis of RF MEMS capacitive shunt switches with high isolation and low Pull-in-Voltage
Microsystem Technologies, 2020Co-Authors: K. Girija Sravani, D. Prathyusha, Ch. Gopichand, Surya Manoj Maturi, Ameen Elsinawi, Koushik GuhaAbstract:This paper presents the design a capacitive shunt type RF-MEMS switch with high isolation, high switching speed and low actuation Voltage for Ka-band applications. The proposed RF-MEMS switch has chosen different structures to reduce the actuation Voltage. This paper investigates various analysis such as Electromechanical and RF characteristics of the proposed switch. The beam material taken as the gold and the dielectric is taken as Si_3N_4 with ℰ_r as 7.5 and the Pull-in Voltage of proposed switch obtained as 3.37 V. The proposed different RF-MEMS switches have been analyzed over the range of 26.5–40 GHz frequency. The clamped-clamped structure type RF MEMS Switch is having high isolation as − 46.37 dB at 40 GHz. The perfection of RF losses makes these switches as a good choice for a high frequency of K-band.
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Analysis of a novel RF MEMS switch using different meander techniques
Microsystem Technologies, 2019Co-Authors: K. Girija Sravani, Koushik Guha, K. Srinivasa RaoAbstract:In this paper, two types of RF MEMS switches namely step structure and Normal beam structure are designed and analyzed using different meander techniques. Three techniques namely plus, zigzag and three-square meander were used to lower the Pull-in Voltage. The actuating beam is designed with the rectangular perforations affects the performance of a switch by lowering the Pull-in Voltage, switching speed and results in better isolation. In this paper a comparative analysis is done for all three meander techniques with and without perforations on the beam. Total six structures have been designed with the combination three meanders and two different beam structures. The proposed stepdown structure exhibits high performance characteristics with a very low Pull-in Voltage of 1.2 V having an airgap of 0.8 µm between the actuation electrodes. The gold is used as beam material and HfO_2 as the dielectric material such that the upstate and downstate capacitance is seen as 1.02 fF and 49 fF. The FEM analysis is done to calculate the spring constant and thereby the Pull-in Voltage and behavior of the switch is studied with various parameters. The switch with a step structure and three-square meander configuration has shown best performance of all by requiring a Pull-in Voltage of 1.2 V and lower switching time of 0.2 µs. The proposed switch also exhibits good RF performance characteristics with an insertion loss below − 0.07 dB and return loss below − 60 dB over the frequency range of 1–40 GHz. At 28 GHz a high isolation of − 68 dB is exhibited.
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Design and Analysis of Serpentine Flexure Based RF MEMS Switch for High Isolation with Low Pull-in Voltage
Transactions on Electrical and Electronic Materials, 2019Co-Authors: K. Girija Sravani, Koushik Guha, K. Srinivasa RaoAbstract:This paper presents the design and performance analysis of radio frequency micro electro mechanical system switches having serpentine flexure designs. In this paper, we have done, behavioral analysis by changing material, gap and thickness, increase in the actuation area using menders, impact of holes on effective working of the switch, stress analysis for low spring constant, electromechanical analysis for low Pull-in Voltage and high capacitance ratio, time dependent analysis for faster switching time, scattering parameter analysis for reducing RF losses are simulated and compared with the theoretical analysis. The significant improvements in this work are lesser air gap and beam thickness reduced the Pull-in Voltage to 2.75 V for 1.66 µm displacement, a rapid switching time of 0.9 µs obtained through simulation, an improved capacitance ratio of 157.25, isolation is 49.59 dB, insertion loss is 0.005 dB. Actuation area is increased, and switch area is reduced to achieve the optimum performance of the switch.
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An improved analytical model for static Pull-in Voltage of a flexured MEMS switch
Microsystem Technologies, 2018Co-Authors: Koushik Guha, N. M. Laskar, H. J. Gogoi, S. Chanda, K. L. Baishnab, N. P. MaityAbstract:This paper presents the design of low-k meander based MEMS shunt capacitive switch with beam perforations. A closed form model to accurately calculate the Pull-in Voltage of the designed switch for two cases have been presented viz. a non-uniform meander based MEMS shunt switch and an uniform serpentine meander based MEMS shunt switch with perforated structure. The modified Mejis and Fokkema’s capacitance model have been used to propose a generalized closed form expression for the Pull-in Voltage which takes care of the nonlinear electrostatic force on the switch as well. The proposed model also takes into account the fringing field effect due to beam thickness and etched holes on the beam. The model is validated by calculating the Pull-in Voltage for both the meander designs under variation of various design parameters. The results obtained under most design specification variation has been found out to be in the range of 1.5–2.3 V for uniform meander based MEMS shunt switch and 3.2–5.2 V for the non-uniform counterpart. The model based results have been further verified by comparison with simulated results of full 3D FEM solver CoventorWare in a wide range of structural parameter variations. It has been observed that the performance of the proposed model is reasonably satisfactory with an average deviation of 4.73% for uniform serpentine flexure and 3.65% for non-uniform flexure based switch.
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Novel analytical model for optimizing the Pull-in Voltage in a flexured MEMS switch incorporating beam perforation effect
Solid-State Electronics, 2017Co-Authors: Koushik Guha, N. M. Laskar, H. J. Gogoi, K. L. Baishnab, A. K. Borah, Srimanta BaishyaAbstract:Abstract This paper presents a new method for the design, modelling and optimization of a uniform serpentine meander based MEMS shunt capacitive switch with perforation on upper beam. The new approach is proposed to improve the Pull-in Voltage performance in a MEMS switch. First a new analytical model of the Pull-in Voltage is proposed using the modified Mejis-Fokkema capacitance model taking care of the nonlinear electrostatic force, the fringing field effect due to beam thickness and etched holes on the beam simultaneously followed by the validation of same with the simulated results of benchmark full 3D FEM solver CoventorWare in a wide range of structural parameter variations. It shows a good agreement with the simulated results. Secondly, an optimization method is presented to determine the optimum configuration of switch for achieving minimum Pull-in Voltage considering the proposed analytical mode as objective function. Some high performance Evolutionary Optimization Algorithms have been utilized to obtain the optimum dimensions with less computational cost and complexity. Upon comparing the applied algorithms between each other, the Dragonfly Algorithm is found to be most suitable in terms of minimum Pull-in Voltage and higher convergence speed. Optimized values are validated against the simulated results of CoventorWare which shows a very satisfactory results with a small deviation of 0.223 V. In addition to these, the paper proposes, for the first time, a novel algorithmic approach for uniform arrangement of square holes in a given beam area of RF MEMS switch for perforation. The algorithm dynamically accommodates all the square holes within a given beam area such that the maximum space is utilized. This automated arrangement of perforation holes will further improve the computational complexity and design accuracy of the complex design of perforated MEMS switch.
Anurekha Sharma - One of the best experts on this subject based on the ideXlab platform.
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A novel method to predict the effect of static charges on the Pull-in Voltage and touch-point pressure of the capacitive transducer with square diaphragm
International Journal of Advances in Engineering Sciences and Applied Mathematics, 2010Co-Authors: Anurekha Sharma, P.j. GeorgeAbstract:Microelectromechanical systems (MEMS) use silicon based dielectric films such as SiO2 and Si3N4 for providing insulation. In capacitive transducers, these layers are used as insulation layers for capacitive actuators to prevent short-circuiting of electrodes by contact of electrodes and in case of touchmode capacitive pressure sensors (TMCPS), the dielectric layer provides for overload protection and provides for operation in the pressure ranges in which the diaphragm comes in contact with dielectric. The pressure at which diaphragm just touches the dielectric is referred to as touch-point pressure. In case of actuator, Pull-in Voltage is a critical parameter that decides the onset of instability in operation of the device. Silicon based dielectric thin films have the tendency to store or trap static charges, the presence of which alters the ideal behaviour of dielectrics. These trapped static charges introduced due fabrication processes; handling and operation affect the operation of capacitive transducers by influencing the Pull-in Voltage and by affecting the touch-point pressure. This paper presents a novel methodology, which predicts the Pull-in Voltage and touch-point pressure in presence of the static charges in a dielectric. The method proposed is less complex and less time consuming. Closed form expressions have been derived for Pull-in Voltage, touch-point pressure and critical displacement in presence of static charges. The results are compared with those obtained by experiment.
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A simple method for calculation of the Pull-in Voltage and touch-point pressure for the small deflection of square diaphragm in MEMS
Sensors and Actuators A-physical, 2008Co-Authors: Anurekha Sharma, P.j. GeorgeAbstract:There are a number of MEMS structures that make use of diaphragms. The deformation of the diaphragm for the purpose of actuation and transduction can be brought about by application of Voltage and/or pressure or any other mechanical excitation like acceleration, force, etc. The amount of deformation can be measured by changes in the capacitance between the diaphragm and the fixed electrode. The gap between the electrodes can be an air gap or can have an intervening layer of the dielectric on the fixed electrode along with the air gap. The Pull-in Voltage and touch-point pressure along with the structural and material properties are critical parameters that decide the behavior of the actuator/transducer. This paper presents a simple methodology, which is capable of representing small deflection of diaphragm with pressure, and/or applied Voltage. The method proposed is less complex and less time consuming in comparison with FEM tools. Closed form expressions have been derived for Pull-in Voltage with/without dielectric between the two electrodes and critical distance for Pull-in. The closed form expressions for touch-point pressure have also been derived. The results are compared with those obtained by simulation as well as experiment.
