scholarly journals The Mechanical Effects Influencing on the Design of RF MEMS Switches

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 207 ◽  
Author(s):  
Igor Lysenko ◽  
Alexey Tkachenko ◽  
Olga Ezhova ◽  
Boris Konoplev ◽  
Eugeny Ryndin ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Microelectromechanical Systems ◽  
Rf Mems ◽  
Negative Impact ◽  
Short Circuit ◽  
Open Circuit ◽  
Operating Conditions ◽  
Strong Impact ◽  
Irreversible Damage ◽  
Mechanical Effects

Radio-frequency switches manufactured by microelectromechanical systems technology are now widely used in aerospace systems and other mobile installations for various purposes. In these operating conditions, these devices are often exposed to intense mechanical environmental influences that have a strong impact on their operation. These negative effects can lead to unwanted short-circuit or open-circuit in the radio-frequency transmission line or to irreversible damage to structural elements. Such a violation in the operation of radio-frequency microelectromechanical switches leads to errors and improper functioning of the electronic equipment in which they are integrated. Thus, this review is devoted to the analysis of the origin of these negative intense mechanical effects of the environment, their classification, and analysis, as well as a review of methods to reduce or prevent their negative impact on the design of radio-frequency microelectromechanical switches.

Micro/Nanotribology of RF MEMS Switches

2004 ◽  
Author(s):  
Steven T. Patton ◽  
Kalathil C. Eapen ◽  
Jeffrey S. Zabinski
Keyword(s):  
Electric Current ◽  
Microelectromechanical Systems ◽  
Rf Mems ◽  
Low Cost ◽  
Operating Conditions ◽  
Great Promise ◽  
Rf Switches ◽  
Mems Switches ◽  
Adhesion Contact ◽  
Rf Mems Switches

Microelectromechanical systems (MEMS) radio frequency (RF) switches hold great promise in a myriad of commercial, aerospace, and military applications. MEMS switches offer important advantages over current electromechanical and solid state technologies including high linearity, low insertion loss, low power consumption, good isolation, and low cost [1–21]. However, there is little fundamental understanding of the factors determining the performance and reliability of these devices. Our previous work investigated fundamentals of hot-switched direct current (DC) gold (Au) contacts using a modified microadhesion apparatus as a switch simulator [1]. Those experiments were conducted under precisely controlled operating conditions in air at MEMS-scale forces with an emphasis on the role of surface forces and electric current on switch performance, reliability, and durability [1]. Electric current had a profound effect on deformation mechanisms, adhesion, contact resistance (R), and reliability/durability. At low current (1–10 μA), asperity creep and switching induced adhesion were the most important observations, whereas, at high current (1–10 mA), lack of adhesion and switch shorting by nanowire formation were prominent [1].

scholarly journals Numerical Modeling of the Electronic and Electrical Characteristics of InGaN/GaN-MQW Solar Cells

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1241 ◽  
Author(s):  
Bilel Chouchen ◽  
Mohamed Hichem Gazzah ◽  
Abdullah Bajahzar ◽  
Hafedh Belmabrouk
Keyword(s):  
Solar Cells ◽  
Quantum Wells ◽  
Negative Impact ◽  
Positive Impact ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
Effect Of Temperature ◽  
Photovoltaic Parameters

In this paper, a numerical model allows to analyze the photovoltaic parameters according to the electronic properties of InxGa1−xN/GaN MQW solar cells under the effect of temperature, the number of quantum wells and indium composition. The numerical investigation starts from the evaluation through the finite difference (FDM) simulation of the self-consistent method coupled with the photovoltaic parameters taking into account the effects of the spontaneous and piezoelectric polarization. The results found were consistent with the literature. As expected, the temperature had a negative impact on the performance of InGaN/GaN MQW solar cells. However, increasing the number of quantum wells improves cell performance. This positive impact further improves with the increase in the indium rate. The obtained results were 28 mA/cm2 for the short-circuit current density, 1.43 V for the open-circuit voltage, and the obtained conversion efficiency was 31% for a model structure based on 50-period InGaN/GaN-MQW-SC under 1-sun AM1.5G.

scholarly journals A Unified Approach for Analysis of Faults in Different Configurations of PV Arrays and Its Impact on Power Grid

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 156 ◽  
Author(s):  
Saba Gul ◽  
Azhar Ul Haq ◽  
Marium Jalal ◽  
Almas Anjum ◽  
Ihsan Ullah Khalil
Keyword(s):  
Thin Film ◽  
Short Circuit ◽  
Power Grid ◽  
Open Circuit ◽  
Fault Analysis ◽  
Operating Conditions ◽  
Power Grids ◽  
Pv System ◽  
Multiple Faults ◽  
The Impact

Fault analysis in photovoltaic (PV) arrays is considered important for improving the safety and efficiency of a PV system. Faults do not only reduce efficiency but are also detrimental to the life span of a system. Output can be greatly affected by PV technology, configuration, and other operating conditions. Thus, it is important to consider the impact of different PV configurations and materials for thorough analysis of faults. This paper presents a detailed investigation of faults including non-uniform shading, open circuit and short circuit in different PV interconnections including Series-Parallel (SP), Honey-Comb (HC) and Total-cross-Tied (TCT). A special case of multiple faults in PV array under non-uniform irradiance is also investigated to analyze their combined impact on considered different PV interconnections. In order to be more comprehensive, we have considered monocrystalline and thin-film PV to analyze faults and their impact on power grids. Simulations are conducted in MATLAB/Simulink, and the obtained results in terms of power(P)–voltage(V) curve are compared and discussed. It is found that utilization of thin-film PV technology with appropriated PV interconnections can minimize the impact of faults on a power grid with improved performance of the system.

scholarly journals Magnetic coupling coefficient determination of IPT systems under operating conditions

2014 ◽  
Vol 1 (2) ◽  
pp. 83-86 ◽  
Author(s):  
A. Abdolkhani ◽  
A.P. Hu
Keyword(s):  
Real Time ◽  
Coupling Coefficient ◽  
Short Circuit ◽  
Magnetic Coupling ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Operating Conditions ◽  
Quality Factors ◽  
Coupling Condition ◽  
Coupled Coils

This study presents a method of determining the magnetic coupling coefficient of inductive power transfer (IPT) systems under real-time operating conditions by measuring the open-circuit voltage and short-circuit current of coupled coils. Besides the theoretical analysis, the proposed method is verified by finite elements simulation and practical evaluation. Both simulation and experimental results have demonstrated that the proposed method can determine the coupling coefficient of both closely and loosely coupled coils with high-quality factors. The method can be used for online monitoring of the coupling condition and real-time power flow controller design of IPT systems.

The modulation of bulk-organic solar cells: the effect of serial and parallel resistances and the relationship with the microscopic morphology

2011 ◽  
Vol 1359 ◽  
Author(s):  
A.J. Trindade ◽  
M.G. Santos ◽  
J. Gomes ◽  
L. Pereira
Keyword(s):  
Organic Solar Cells ◽  
Bulk Heterojunction ◽  
Short Circuit ◽  
Acid Methyl Ester ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Relevant Parameter ◽  
Strong Impact ◽  
Microscopic Morphology ◽  
The Relationship

ABSTRACTThis work shows the relationship between the morphology (studied by AFM) of an active bulk-heterojunction (BHJ) layer composed by MEH-PPV (poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene) and PCBM ([6,6]-phenyl-C61-butyric acid methyl ester) and the respective photovoltaic figures of merit. It is observed that the most relevant parameter (influencing the efficiency) is the fill-factor (FF), as both the open circuit voltage and short circuit current are not significantly affected by the microscopic morphology. Different local conformation of the active films can change the FF from near 25% to more than 65%, having a strong impact in the efficiency. These results were modulated by an equivalent circuit. Serial and parallel resistances were related with the physical behavior of the organic cells. These were observed to have a direct relationship with the achieved morphology.

scholarly journals Analytical Approach in the Development of RF MEMS Switches

Electronics ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 415 ◽  
Author(s):  
Igor Lysenko ◽  
Alexey Tkachenko ◽  
Elena Sherova ◽  
Alexander Nikitin
Keyword(s):  
Integrated Circuits ◽  
Radio Frequency ◽  
High Frequency ◽  
High Performance ◽  
Analytical Approach ◽  
Microelectromechanical Systems ◽  
Rf Mems ◽  
Frequency Control ◽  
High Ratio ◽  
Control Circuits

Currently, the technology of microelectromechanical systems is widely used in the development of high-frequency and ultrahigh-frequency devices. The most important requirements for modern and advanced devices of the ultra-high-frequency range are the reduction of weight and size characteristics, power consumption with an increase in their functionality, operating frequency and level of integration. Radio frequency microelectromechanical switches are developed using the technology of the manufacture of CMOS-integrated circuits. Integrated radio frequency control circuits require low control voltages, the high ratio of losses to the isolation in the open and closed condition, high performance and reliability. This review is devoted to the analytical approach based on the knowledge of materials, basic performance indices and mechanisms of failure, which can be used in the development of radio-frequency microelectromechanical switches.

Method of Fast Hydrogen Passivation to Solar Cell Made of Crystalline Silicon

2008 ◽  
Vol 1123 ◽  
Author(s):  
Wen-Ching Sun ◽  
Jian-Hong Lin ◽  
Wei-Lun Chang ◽  
Tien-Heng Huang ◽  
Chih-Wei Wang ◽  
...  
Keyword(s):  
Solar Cell ◽  
Open Circuit Voltage ◽  
Crystalline Silicon ◽  
Short Circuit ◽  
Open Circuit ◽  
Crystal Defects ◽  
Operating Conditions ◽  
Hydrogen Ions ◽  
Short Period ◽  
Plasma Immersion Ion Implantation

AbstractPlasma immersion ion implantation (PIII) is a technique of material processing and surface modification, using controllable negative high voltage pulsed bias to attract the ion generated from the plasma. The method using PIII treatment quickly improves the performance of solar cell made of crystalline silicon, including monocrystalline, multicrystalline and polycrystalline silicon. Hydrogen ions are attracted and quickly implanted into solar cell under a predetermined negative pulse voltage, thus, the passivation of the crystal defects of the solar cell can be realized in a short period. Meanwhile, the properties of the antireflection layer can not be damaged as the proper operating conditions are used. Consequently, the series resistance can be significantly reduced and the filling factor increases as a result. Both the short-circuit and the open-circuit voltage can be increased. The efficiency can be enhanced.

scholarly journals Deactivation of Commercial, High-Load o-Xylene Feed VOx/TiO2 Phthalic Anhydride Catalyst by Unusual Over-Reduction

Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 435 ◽  
Author(s):  
Oliver Richter ◽  
Gerhard Mestl
Keyword(s):  
Phthalic Anhydride ◽  
Catalyst Deactivation ◽  
Negative Impact ◽  
Catalyst Layer ◽  
Systematic Investigation ◽  
Significant Loss ◽  
Operating Conditions ◽  
Physical Analysis ◽  
Irreversible Damage ◽  
Catalyst Poisons

An unusual temporal behavior of the by-product spectrum, as well as the temperature profiles of a commercial phthalic anhydride reactor, indicated a non-typical change of the incumbent catalyst. In order to understand these observations, catalyst samples were taken from this reactor and analyzed by standard physico-chemical methods. Catalyst samples from another commercial reference reactor with most similar operating conditions and catalyst lifetime were also taken for comparison. The detailed physical analysis did not indicate unusual thermal stress leading to catalyst deactivation by rutilisation or sintering of the titania phase. The chemical analysis did not reveal significant amounts of any of the known catalyst poisons, which would also contribute to an untypical catalyst deactivation/behavior. Quantitative X-ray diffraction measurements on the other hand revealed an unusually high degree of reduction of the vanadium species in the final polishing catalyst layer. Such an abnormal degree of catalyst reduction, and hence, irreversible damaging, was concluded to likely originate from a unit shutdown without sufficient air purging of the catalyst bed. Combustion analysis of the deactivated catalyst confirmed unusually high carbon contents in the finishing catalyst bed (L4) accompanied with a significant loss in the specific surface area by plugging the catalyst pores with high-molecular carbon deposits. According to the well-known Mars–van-Krevelen-mechanism, o-xylene and reaction intermediates remain adsorbed on the catalyst surface in case of a shutdown without air purging and will continue to consume lattice oxygen, accordingly reducing the catalytic species. This systematic investigation of used catalyst samples demonstrated the importance of sufficient air purging during and after a unit shutdown to avoid abnormal, irreversible damage and thus negative impact to catalyst performance.

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