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Midtflå, Roar. "RF MEMS". Thesis, Norwegian University of Science and Technology, Department of Electronics and Telecommunications, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-10337.
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Fagområdet RF MEMS er i rask utvikling og det finnes et utall forskjellige patenter innen dette området. Denne oppgaven fokuserer på en type nemlig radial contour mode diskresonator med sikte på å bruke den i SMiDA prosjektet Mer spesifikt går oppgaven ut på å teste forskjellige diskparametre for å finne ut hvilken som er best egnet. Noe konkret svar på dette finnes ikke, men det kan være interessant å bruke 2.mode til en disk på 16μm eller 3.mode til en disk på 20μm. En fant også frem til et spesielt design som gav veldig høy radiell amplitude i 1.mode.
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Adamec, Richard. "MEMS Anemometer". Thesis, Griffith University, 2007. http://hdl.handle.net/10072/365273.
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A MEMS hot wire anemometer was designed, simulated, fabricated and tested. The device was of a planar silicon substrate construction measuring wind direction in two dimensions. Wind velocity and temperature were also measured with the same sensing elements on the device. This anemometer formed part of a multisensor incorporating other sensing functions such as humidity and light onto a common silicon substrate compatible with active electronics integration. Of these sensors only temperature, wind speed and direction are presented as the work of this thesis, however integration of each of these sensors within the larger multisensor was a necessary consideration. Also presented are the results of the prototype devices constructed from discrete surface mount components offering device alternatives dependant on application.
Simulation and development was aided with Coventorware multiphysics modelling software providing virtual analysis in electrical, thermal and fluidic domains. Fabrication was primarily conducted within the Griffith University fabrication laboratory with a subsequent fabrication run of four wafers in a commercial foundry hosted by Motorola. Packaging options were developed for the silicon die consisting of either conventional chip carriers or application specific fibreglass carriers. Prototype packaging was also developed for the larger complete system incorporating the interface electronics and communications system.
Testing was conducted in the laboratory in a controlled environmental chamber and wind tunnel built to calibrate the devices. Laboratory results are reported for the controlled environment response to demonstrate the consistency and accuracy obtained during testing. Wind tunnel testing was conducted both on the carrier mounted die and on the larger self contained system to be deployed into the field trial incorporating all interface electronics and the communications system. Field trial testing was employed to evaluate the devices under continued operation when exposed to typical environmental abuse such as thermal cycling and physical contamination over time. The field trial results present a typical 24 hour period of operation measured against a commercially available weather station mounted in the same location for reference.
The results from the laboratory and field trial testing demonstrated the sensor operational and meeting the design requirements, showing a velocity range exceeding 0-30m/s ±10%, directional accuracy of better than 8° and power consumption of 45mW. This was achieved in a die size 42% of that allowable in the design requirements. Fabrication process requirements were largely CMOS compatible and was demonstrated with the integration of a diode on the same silicon die.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Engineering
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Saha, Shimul Chandra. "RF MEMS Switches and Switch Circuits : Modeling of RF MEMS switches and development of RF MEMS capacitive switches and MEMS tunable filters". Doctoral thesis, Norwegian University of Science and Technology, Department of Electronics and Telecommunications, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-2297.
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Hedestig, Joel. "MEMS baserad referensoscillator". Thesis, Linköpings universitet, Institutionen för systemteknik, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2780.
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The interest in tiny wireless applications raises the demand for an integrated reference oscillator with the same performance as the macroscopic quartz crystal reference oscillators. The main challenge of the thesis is to prove that it is possible to build a MEMS based oscillator that approaches the accuracy level of existing quartz crystal oscillators. The MEMS resonator samples which Philips provides are measured and an equivalent electrical model is designed for them. This model is used in the simulations of the Pierce oscillator and the transresistance amplifier oscillator that are evaluated in this thesis. Finally the Pierce oscillator is implemented in the A BCD2 process and manufactured at Philips Semiconductors in Nijmegen, The Netherlands. A test board, for measuring the Pierce oscillator together with a MEMS resonator or a quartz crystal resonator, is built. The Pierce oscillator is then measured with a quartz crystal resonator. In order to simulate the higher series resistance of the MEMS resonators a resistor is put in series with the quartz crystal. The Pierce oscillator is working with a series resistance of 1 kΩ. With higher series resistance the Pierce oscillator stops working. In circuit simulations the Pierce oscillator is working with a series resistance of about 5 kΩ in the MEMS resonator model. To be sure whether the Pierce oscillator has enough gain for the MEMS resonators, it needs to be measured with them. Temperature variations in the MEMS resonators need to be handled and the phase noise performance of the oscillator must be improved, in order for the MEMS based reference oscillator to be a successful replacement for the quartz crystal reference oscillator.
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Larsson, Michael Peter. "MEMS electrical connectors". Thesis, Imperial College London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439300.
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Cao, J. "Magnetic MEMS actuators". Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.597277.
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Magnetic MEMS actuators are presently still relatively under-researched as compared to their electrostatic, piezoelectric and electro-thermal counterparts. Most existing magnetic MEMS actuators are limited to simply delivering a rotational output. The research presented in this thesis aims to develop novel magnetic MEMS actuators with complex structures that are capable of delivering more sophisticated and useful mechanical outputs than the existing devices. The study begins with an attempt to solve the problem of bending a freestanding ferromagnetic cantilever beam with an applied magnetic field. Analytical and numerical models have been constructed and the modelling results are compared to experimental results obtained from a microscopic and a laser measurement system. NiFe alloy has been used as both the magnetic and mechanical element. The magnetic and mechanical properties of electroplated NiFe have been experimentally characterized. Fabrication processes for creating freestanding NiFe structures have been designed and optimized via a parametric experimental study. Finally, novel ferromagnetic microstructures have been designed by combining the motions of more than one ferromagnetic beam. Preliminary magnetic actuation tests have been carried out in order to verify the design ideas.
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Ismail, Abd Khamim. "MEMS mass sensor". Thesis, University of Newcastle Upon Tyne, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430353.
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Hasík, Stanislav. "Testování MEMS gyroskopů". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-240919.
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This diploma thesis presents theoretical information regarding MEMS gyroscopes their parameters and designs. The description of measurement chain be used for testing of MEMS gyroscopes in Honeywell International s.r.o. is presented. Special focus is devoted to: the Polytec MSA-500 system, the Standa goniometers and their controller, Peltier cell and its driver. The practical part of this thesis contains the description of the thermal control system and also the description of the developed “Measurement system” in the LabVIEW software which is used for controlling the goniometers position and the Peltier cell. The system is able to fully control two goniometer stages, align the surface of tested MEMS device to orthogonal position with respect to the Polytec MSA-500 measurement head and also control the temperature of the tested device. The last part of this thesis presents the tests of the MEMS gyroscope parameters with special focus to the MEMS gyroscope angle random walk and the bias dependence on the vacuum quality of the structure environment.
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Izham, Zaki. "Resonant MEMS magnetometer". Thesis, University of Birmingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436751.
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Mihaľko, Juraj. "MEMS inerciální snímače". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219724.
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The aim of this master’s thesis is to describe the basic measurement methods of micro-electromechanical inertial sensor, their physical principles and errors. Measurement of inertial sensors is very important for the parameterization of their errors and their subsequent mathematical model by which it is possible to minimize the measurement error impact on inertial navigation. The practical part is dedicated to create automated measurement setup for measurement stability of the offset. Hardware and software from National Instruments is used in measurement chain. The work is next focused on measuring seven inertial sensors based on three different physical principles. In addition to creating measurement setup, we also defined three inertial sensor parameters, describing theoretical behavior of the sensor output.
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Arrigoni, Giacomo. "Commande pour MEMS électrostatique /". Sion, 2008. http://doc.rero.ch/record/12798?ln=fr.
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Kotovsky, Jack. "MEMS contact stress sensing /". For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2005. http://uclibs.org/PID/11984.
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Specht, Hendrik. "MEMS-Laser-Display-System". Doctoral thesis, Universitätsbibliothek Chemnitz, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-71334.
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In der vorliegenden Arbeit werden die im Zusammenhang mit der Strahlablenkung stehenden Systemaspekte der auf MEMS-Scanner basierenden Laser-Display-Technologie theoretisch analysiert und aus den Ergebnissen die praktische Implementierung eines Laser-Display-Systems als Testplattform vorgenommen. Dabei werden mit einem Ansatz auf Basis zweier 1D-Scanner und einem weiteren Ansatz mit einem 2D-Scanner zwei Varianten realisiert. Darüber hinaus erfolgt die Entwicklung eines bildbasierten Multiparametertestverfahrens, welches sowohl für den Test komplettierter Strahlablenkeinheiten bzw. Projektionsmodule als auch zum umfassenden und zeiteffizienten Test von MEMS-Scannern auf Wafer-Level geeignet ist. Mit diesem Verfahren erfolgt eine Charakterisierung der zwei realisierten Varianten des Laser-Displays.
Ausgehend von den Eigenschaften des menschlichen visuellen Systems und den daraus resultierenden Anforderungen an das Bild sowie einer systemtheoretischen Betrachtung des mechanischen Verhaltens von MEMS-Scannern bildet die Ansteuersignalerzeugung für den resonanten Betrieb der schnellen und den quasistatischen Betrieb der langsamen Achse einen Schwerpunkt. Neben dem reinen digitalen Regler- bzw. Filterentwurf sowie mehreren Linearisierungsmaßnahmen beinhaltet dieser auch die Herleitung einer FPGA-basierten Videosignalverarbeitung zur Konvertierung von Scannpattern, Zeitregime und Auflösung mit einer entsprechenden Synchronisierung von Strahlablenkung und Lasermodulation. Auf Grundlage der daraus resultierenden Erkenntnisse über den Zusammenhang zwischen Scanner-/Systemparametern und Bildparametern werden Testbild-Bildverarbeitungsalgorithmus-Kombinationen entwickelt und diese, angeordnet in einer Sequenz, mit einem Kalibrierverfahren zu einem Testverfahren für MEMS-Scanner vervollständigt.
Die Ergebnisse dieser Arbeit entstanden im Rahmen von industriell beauftragten F&E-Projekten und fließen in die andauernde Fortführung des Themas beim Auftraggeber ein.
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Azgin, Kivanc. "High Performance Mems Gyroscopes". Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608194/index.pdf.
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This thesis reports development of three different high performance, low g-sensitive micromachined gyroscopes having single, double, and quadruple masses. The single mass gyroscope (SMG) is developed for comparison of its performance with the double mass gyroscope (DMG) and quadruple mass gyroscope (QMG). DMG is a tuning fork gyroscope, diminishing the effects of unpredictable g-loadings during regular operation, while QMG is a twin tuning fork gyroscope, developed for a uniform and minimized g-sensitivity. DMG and QMG use novel ring spring connections for merging the masses in drive modes, providing uniform and anti-phase drive mode vibrations that minimize the cross-coupling and the effects of intrinsic and extrinsic accelerations on the scale factor and bias levels of the gyroscopes. The sense mode of each mass of the multi-mass gyroscopes is designed to have higher resonance frequencies than that of the drive mode for possible matching requirements, and these sense modes have dedicated frequency tuning electrodes for frequency matching or tuning. Detailed performance simulations are performed with a very sophisticated computer model using the ARCHITECT software.
These gyroscopes are fabricated using a standard SOIMUMPs process of MEMSCAP Inc., which provides capacitive gaps of 2 µm and structural layer thickness of 25 µ
m. Die sizes of the fabricated gyroscope chips are 4.1 mm x 4.1 mm for the single mass, 4.1 mm x 8.9 mm for the double mass, and 8.9 mm x 8.9 mm for the quadruple mass gyroscope. Fabricated gyroscopes are tested with dedicated differential readout electronics constructed with discrete components. Drive mode resonance frequencies of these gyroscopes are in a range of 3.4 kHz to 5.1 kHz. Depending on the drive mode mechanics, the drive mode quality (Q) factors of the fabricated gyroscopes are about 300 at atmospheric pressure and reaches to a value of 2500 at a vacuum ambient of 50 mTorr. Resolvable rates of the fabricated gyroscopes at atmospheric pressure are measured to be 0.109 deg/sec, 0.055 deg/sec, and 1.80 deg/sec for SMG, DMG, and QMG, respectively. At vacuum, the respective resolutions of these gyroscopes improve significantly, reaching to 106 deg/hr with the SMG and 780 deg/hr with the QMG, even though discrete readout electronics are used. Acceleration sensitivity measurements at atmosphere reveal that QMG has the lowest bias g-sensitivity and the scale factor g sensitivity of 1.02deg/sec/g and 1.59(mV/(deg/sec))/g, respectively. The performance levels of these multi-mass gyroscopes can be even further improved with high performance integrated capacitive readout electronics and precise sense mode phase matching.
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Dimitrakopoulos, Nikolaos. "Electromagnetic MEMS RF Switch". Thesis, University of Leeds, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485179.
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This thesis describes the design, fabrication and test of an electromagne~ically actuated RF MEMS switch. The actuator was fabricated using two different wafers. The first is steel where the coil is been made with a soft magnetic material forming an inner and an outer pole. On the saine wafer the transmission line and'the beam support are present. Silicon has been used as the second wafer to fabricate the mover. The mover consists of the same soft magnetic material as used for the pot core. The switch contact along with the soft magnet is held by a fixed-fixed SU-8 beam. The mover is finally been released from the silicon wafer and dropped on the actuator using the traditio!1al flip chip method. SU-8 which is a negative tone photoresist has been extensively used in this project. .,- Firstly by using standard lithography methods, it has been patterned to form a mould for the coil. Secondly it provides a dielectric as the transmission line is fabricated on top of it. Then it has been used as a mixture with particles of Iron (Fe) and Nickel (Ni). This soft magnetic composite is used for the inner and outer poles of the pot core and also as the magnet that sits on top of the coilto form the mover. Finally SU-8 forms the fixed-fixed beam and its support underneath. In this work there are a number of combinations presented as far as the device is· concerned. There are 28 ~witches accommodated on a 2 inch wafer. The footprint of each .device is 5x4 mm2 mainly due to the beam length. Microstrip and cpw MEMS switches have been fabricated with the latter using both a series and a shunt configuration. The isolation using a 100 J.1m break between the signal lines was measured to be 44.7 dB although the simulated model estimated 54 dBs at 10 GHz. The insertion loss for a cpw series switch was measured to be 0.38 dB at the same frequency. The switching on and off time of the device was measured to be 7 ms and 1 J.1S respectively. The coil requires a 1.2 A current to actuate the mover from a 50 J.1m distance.
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Tse, Laam Angela. "MEMS packaging with stereolithography". Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/17025.
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Popa, Laura C. "Gallium nitride MEMS resonators". Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/99296.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 187-206).
As a wide band-gap semiconductor, with large breakdown fields and saturation velocities, Gallium Nitride (GaN) has been increasingly used in high-power, high-frequency electronics and monolithic microwave integrated circuits (MMICs). At the same time, GaN also has excellent electromechanical properties, such as high acoustic velocities and low elastic losses. Together with a strong piezoelectric coupling, these qualities make GaN ideal for RF MEMS resonators. Hence, GaN technology offers a platform for the seamless integration of low-loss, piezoelectric RF MEMS resonators with high power, high frequency electronics. Monolithic integration of MEMS resonators with ICs would lead to reduced parasitics and matching constraints, enabling high-purity clocks and frequency-selective filters for signal processing and high-frequency wireless communications. This thesis highlights the physics and resonator design considerations that must be taken into account in a monolithically integrated solution. We then show devices that achieve the highest frequency-quality factor product in GaN resonators to date (1.56 x 1013). We also highlight several unique transduction mechanisms enabled by this technology, such as the ability to use the 2D electron gas (2DEG) channel of High Electron Mobility Transistors (HEMTs) as an electrode for transduction. This enables a unique out-of-line switching capability which allowed us to demonstrate the first DC switchable solid-state piezoelectric resonator. Finally, we discuss the benefits of using active HEMT sensing of the mechanical signal when scaling to GHz frequencies, which enabled the highest frequency lithographically defined resonance reported to date in GaN (3.5 GHz). These demonstrated features sh
by Laura C. Popa.
Ph. D.
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Schaevitz, Samuel B. (Samuel Benjamin) 1978. "A MEMS thermoelectric generator". Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/28253.
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Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.Includes bibliographical references (p. 153-163).
The demand for portable power is large and expanding. Technologies currently available to meet this demand include batteries, fuel cells, thermophotovoltaic (TPV) generators and thermoelectric (TE) generators. Fuel cells and generators offer significantly improved performance over batteries, but issues of fuel processing and miniaturization remain. Microfabrication has the potential to address this miniaturization. Here I present work towards a thermoelectric generator based on micro-electro-mechanical system (MEMS) fabrication technologies. This thesis includes an examination of the current state of the portable power field, followed by an explanation of the thermoelectric effects and the operation of thermoelectric generators. A new analysis of the efficiency of thermoelectric devices, including parasitic losses, is included, with a detailed derivation in an appendix. The design of a prototype MEMS thermoelectric generator is presented, analyzed and fabricated. Testing shows the device performs as expected thermally. However, mechanical fragility causes very low yield during fabrication and limits the high temperature operation. Poor electrical contacts are also observed and characterized. Directions for future work are suggested to improve the efficiency and mechanical strength of the device.
by Samuel B. Schaevitz.
M.Eng.
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Eves, Daniel Patrick. "Materials for magnetic MEMS". Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612715.
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Middlemiss, Richard Paul. "A practical MEMS gravimeter". Thesis, University of Glasgow, 2016. http://theses.gla.ac.uk/7788/.
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The ability to measure tiny variations in the local gravitational acceleration allows – amongst other applications – the detection of hidden hydrocarbon reserves, magma build-up before volcanic eruptions, and subterranean tunnels. Several technologies are available that achieve the sensitivities required (tens of μGal/√Hz), and stabilities required (periods of days to weeks) for such applications: free-fall gravimeters, spring-based gravimeters, superconducting gravimeters, and atom interferometers. All of these devices can observe the Earth tides; the elastic deformation of the Earth’s crust as a result of tidal forces. This is a universally predictable gravitational signal that requires both high sensitivity and high stability over timescales of several days to measure. All present gravimeters, however, have limitations of excessive cost (£70 k) and high mass (<8 kg). In this thesis, the building of a microelectromechanical system (MEMS) gravimeter with a sensitivity of 40 μGal/√Hz in a package size of only a few cubic centimetres is discussed. MEMS accelerometers – found in most smart phones – can be mass-produced remarkably cheaply, but most are not sensitive enough, and none have been stable enough to be called a ‘gravimeter’. The remarkable stability and sensitivity of the device is demonstrated with a measurement of the Earth tides. Such a measurement has never been undertaken with a MEMS device, and proves the long term stability of the instrument compared to any other MEMS device, making it the first MEMS accelerometer that can be classed as a gravimeter. This heralds a transformative step in MEMS accelerometer technology. Due to their small size and low cost, MEMS gravimeters could create a new paradigm in gravity mapping: exploration surveys could be carried out with drones instead of low-flying aircraft; they could be used for distributed land surveys in exploration settings, for the monitoring of volcanoes; or built into multi-pixel density contrast imaging arrays.
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Klempa, Jaroslav. "Sběr energie pomocí MEMS". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-399468.
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This work is dedicated to principles of energy harvesting or scavenging from free energy around us. Energy harvesting principles are described in the first part. Following chapter is devoted to description of piezoelectricity and piezoelectric materials. Next part researches already reported results on piezoelectric energy harvesters. Following chapter shows simulations on designed structures in ANSYS® Workbench. Next the fabrication of the structures is described. Measurement are made regarding to maximum generated power.
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Pehlivanoglu, Ibrahim Engin. "SILICON CARBIDE MEMS OSCILLATOR". Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1196372276.
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Yao, Tze-Jung Tai Yu-Chong. "Parylene for MEMS applications /". Diss., Pasadena, Calif. : California Institute of Technology, 2002. http://resolver.caltech.edu/CaltechETD:etd-07202004-135306.
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Ryšavý, Jindřich. "Předzesilovač pro MEMS mikrofon". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-242074.
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Thesis discusses the possibility of using MEMS microphones in measuring systems. Describes the characteristics of MEMS components and shows possible realization of analog to digital signal convertor when a microphone with analog output is used. Design of the amplifier is made with respect to low noise and low power consumption. Also is shown the possibility of using antialliasing filter as microphone frequency response correction at the same time.
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Pavageau, Franklin. "Actionneurs piézoélectriques MEMS transparents". Electronic Thesis or Diss., Université Grenoble Alpes, 2024. http://www.theses.fr/2024GRALT018.
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La fonctionnalisation de surface de type verre ou souple avec des dispositifs actionneurs MEMS piézoélectriques transparents permettrait l’émergence de nouvelles applications, notamment dans les domaines de l’haptique tactile ou des interfaces homme-machine. Toutefois, il existe des problématiques liées au budget thermique du recuit de cristallisation du PZT (typiquement 700°C), matériau piézoélectrique actionneur roi. En effet, les substrats de verre standard atteignent leur point de déformation vers 450°C. De plus, les électrodes transparentes, en particulier l’ITO, peuvent voir leur résistivité augmenter à haute température. C’est pourquoi le CEA-LETI a mis au point un procédé de report de couches de wafer à wafer pour contourner ces problématiques. Les empilements piézoélectriques à base de PZT à l’état de l’art ainsi transférés présentent des propriétés similaires voire identiques avant et après transfert, que ce soit sur substrat verre ou substrat Si. Des dispositifs fonctionnels tels que des membranes piézoélectriques sur Si et des capacités de type actionneurs sur verre, ayant en moyenne 75 à 80 % de transmission dans le visible, ont ainsi été réalisés et caractérisés. Par ailleurs, la mise en évidence de la bonne tenue en température de l’ITO, recuit à 700°C sous air, présentant une résistivité égale à 5x10−4 Ω.cm, considéré comme peu résistif pour ce matériau, a motivé l’évaluation de dépôts sol-gel de PZT directement sur ITO. Les propriétés du PZT d’épaisseur 500 nm ainsi déposé sur 500 nm d’épaisseur d’ITO sont très encourageantes, avec par exemple un coefficient piézoélectrique d33, f max de l’ordre de 100 pm/V, se rapprochant de l’état de l’art. L’ajout d’une couche antireflet à base de SiO2, optimisée en épaisseur, jouant également le rôle de passivation sur nos condensateurs, a ensuite permis de gagner en moyenne 10 % de transmission. Enfin, des simulations optiques montrent qu’en jouant sur les épaisseurs des couches, par exemple en réduisant les épaisseurs des électrodes ITO à 50-60 nm, des transmissions moyennes de 90 % sont atteignablesThe functionalization of glass or flexible surfaces with transparent piezoelectric MEMS actuator devices would allow the emergence of new applications, particularly in the areas of tactile haptics or human-machine interfaces. However, there are some issues related to the thermal budget of the crystallization annealing of PZT (typically 700°C), the best piezoelectric material for actuator applications. In fact, standard glass substrates reach their deformation point around 450°C. Additionally, transparent electrodes, particularly ITO, may see their resistivity increase at high temperatures. This is why CEA-LETI has developed a process for transferring layers from wafer to wafer to circumvent these problems. The state-of-the-art PZT-based piezoelectric stacks thus transferred have similar or even identical properties before and after transfer, either on a glass substrate or on a Si substrate. Functional devices such as piezoelectric membranes on Si and actuator type capacitors on glass, having on average 75 to 80 % transmission in the visible, were thus produced and characterized. Furthermore, the demonstration of the good temperature resistance of ITO, annealed at 700°C in air, presenting a resistivity equal to 5x10−4 Ω.cm, considered to be low resistive for this material, motivated the evaluation of PZT sol-gel depositon directly on ITO. The properties of the 500 nm thick PZT thus deposited on 500 nm thick ITO are very encouraging, with for example a piezoelectric coefficient d33,f max of the order of 100 pm/V, approaching the state art. The addition of an anti-reflective layer based on SiO2, optimized in thickness, also playing the role of passivation on our capacitors, then made it possible to gain on average 10 % in transmission. Finally, optical simulations show that by varying the thicknesses of the layers, for example by reducing the thicknesses of the ITO electrodes down to 50-60 nm, average transmissions of 90 % are achievable
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Maddela, Madhurima Ramadoss Ramesh. "Design of MEMS-based tunable antennas, organic transistors and MEMS-based organic control circuits". Auburn, Ala, 2008. http://repo.lib.auburn.edu/2007%20Fall%20Dissertations/Maddela_Madhurima_8.pdf.
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Uzunlar, Erdal. "Improvements for chip-chip interconnects and MEMS packaging through MEMS materials and processing research". Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53509.
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Improvements for Chip-Chip Interconnects and MEMS Packaging Through
Materials and Processing Research
Erdal Uzunlar
129 Pages
Directed by Dr. Paul A. Kohl
The work presented in this dissertation focuses on improvements for ever-evolving modern microelectronic technology. Specifically, three topics were investigated in this work: electroless copper deposition on printed wiring boards (PWBs), polymer-based air-gap microelectromechanical systems (MEMS) packaging technology, and thermal stability enhancement in sacrificial polymers, such as poly(propylene carbonate) (PPC). In the electroless copper deposition study, Ag-based catalysts were identified as a low-cost and equally active alternative to expensive Pd-based catalysts. Hot H2SO4 treatment of PWBs was found as a non-roughening surface treatment method to minimize electrical losses. In MEMS packaging study, a sacrificial polymer-based air-gap packaging technique was improved in terms of identification and simplification of air-gap formation process options, optimization of thermal treatment steps, assessing air-gap formation performance, and analyzing the chemical composition of residue. It was found that non-photosensitive PPC leaves less residue, and creates more reliable air-gaps. The mechanical strength of air-gaps was found to come from residual stress in benzocyclobutene (BCB) caps. In thermal stability of PPC study, the mechanism of thermal stability increase on copper (Cu) surfaces was found as the complex formation between Cu(I) and iodonium of the photoacid generator (PAG), leading to hindrance of acid formation by PAG and restriction of acid-catalyzed decomposition of PPC.
28
Pourkamali, Anaraki Siavash. "Electrically Coupled MEMS Bandpass Filters". Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5250.
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This dissertation reports, for the first time, on the electrical coupling of microelectromechanical (MEM) resonators for high order bandpass filter synthesis. Electrical coupling of MEM resonators has a strong potential for extension of the operating frequency of MEM bandpass filters into the ultra high frequency (UHF) range and provides higher tunability and design flexibility compared to the mechanical coupling approach. Various schemes of electrical coupling are presented in this dissertation. Electromechanical models of clamped-clamped beam resonators, and various types of electrically coupled filters are presented. Lower frequency prototypes of electrically coupled filters with operating frequencies in the hundreds of kHz are implemented using micromechanical single crystal silicon clamped-clamped beam resonators. Measurement results are in good agreement with the developed electrical equivalent models of the filters. It is demonstrated that the characteristics of electrically coupled filters can be widely tuned by changing the DC polarization voltages.
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Ocak, Ilker Ender. "A Tactical Grade Mems Acceleroemeter". Phd thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612724/index.pdf.
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Micromachining technologies enabled the use of miniaturized transducers in many high technology sensing systems. These transducers have many advantages like small-size, low-cost and high-reliability. One of the applications micro-machined transducers are used is inertial navigation systems, where the exact position of a moving frame is continuously monitored by tracking the linear and angular motions of the frame. Other than navigation applications, inertial sensors are used in health and military applications as well as consumer electronics. Today accelerometers capable of measuring accelerations from 0.5g-1g range up to several thousand g&rsquos are commercially available in the market which have been fabricated using micromachining technologies. The aim of this research is to develop such a state-of-the-art micro-machined accelerometer system, whose performance is expected to reach tactical-grade level. In order to achieve these performance values a MATLAB algorithm is developed to optimize the accelerometer performances in the desired levels. Expected performance parameters of the designed accelerometer structures are extracted from the simulations done by both Coventorware finite element modeling tool and MATLAB. Designed structures are then fabricated with silicon-on-glass, dissolved wafer and dissolved epitaxial wafer processes. These fabrication results are compared and it is observed that highest yield accelerometers are fabricated with the SOG process. But these accelerometers could not be able to satisfy tactical grade performance parameters. Best performances are obtained with DWP, but due to high internal stress, yield of the sensors were very low. DEWP increased the yield of this process from 2-3% to 45-50% but the expected operation range of the designs dropped to ±
12.5g range. Using the fabricated accelerometers in DEWP a three axial accelerometer package is prepared and tests results proved that this three axial accelerometer system was satisfying the tactical grade requirements. In addition to these a three axial monolithic accelerometer fabrication technique is proposed and sensors are designed which are suitable for this process. Best performances achieved with single axis accelerometers were 153µ
g/&radic
Hz noise floor, 50µ
g bias drift, 0.38% non-linearity and a maximum operation range of 33.5g which has the higher dynamic range among its counterparts in the literature. Performance results achieved with the three axes accelerometer were ~150µ
g bias drift, <
200µ
g/&radic
Hz noise density, ~0.4% non-linearity with higher than ±
10g operation range.
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Diamantis, Sotirios. "A programmable MEMS bandpass filter". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ62206.pdf.
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Bell, Patrick J. "MEMS-reconfigurable microwave power amplifiers". Diss., Connect to online resource, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3219036.
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Frisk, Thomas. "MEMS interfaces for bioanalysis systems /". Stockholm : Elektriska energisystem, Kungliga Tekniska högskolan, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4609.
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Naumann, Michael. "MEMS reliability in shock environments". Doctoral thesis, Universitätsbibliothek Chemnitz, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-117360.
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In der vorliegenden Arbeit wird eine Methode vorgestellt, mit welcher die Zuverlässigkeit mikroelektromechanischer Systeme (MEMS) bezüglich stoßinduzierter Fehlermechanismen bereits in der Entwurfsphase neuer Produkte abgeschätzt bzw. verbessert werden kann. Der Ansatz bezieht sich dabei auf bruch- sowie adhäsionsbedingte Ausfallmechanismen und erfordert zwei wesentliche Schritte. Zuerst werden Systemmodelle der jeweils zu untersuchenden mikromechanischen Systeme erstellt, welche die Berechnung der Stoßantwort wie auch der dabei auftretenden Belastungen in Sinne von Auslenkungen, Deformationen und Aufprallkräften ermöglichen. In einem zweiten Schritt wird die zur Fertigung vorgesehene Technologie bezüglich des Auftretens beider stoßbedingter Ausfallmechanismen sowie deren Abhängigkeit von verschiedenen Umgebungsbedingungen oder Betriebsparametern systematisch untersucht. Die aus der Prozesscharakterisierung resultierenden Daten dienen zur Ableitung prozessspezifischer Fehlerkriterien, welche die Einschätzung der zuvor berechneten Lasten ermöglichen. Auf diese Weise kann abgeschätzt werden, inwieweit die Zuverlässigkeit der betrachteten mikromechanischen Strukturen beeinflusst wird bzw. mit welchen Maßnahmen diese gesteigert werden kann.
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Forsberg, Fredrik. "Heterogeneous material integration for MEMS". Doctoral thesis, KTH, Mikro- och nanosystemteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-129185.
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This thesis describes heterogeneous integration methods for the fabrication of microelectromechanical systems (MEMS). Most MEMS devices reuse the fabrication techniques that are found in the microelectronics integrated circuit industry. This limits the selection of materials and processes that are feasible for the realization of MEMS devices. Heterogeneous integration methods, on the other hand, consist of the separate pre-fabrication of sub-components followed by an assembly step. The pre-fabrication of subcomponents opens up for a wider selection of fabrication technologies and thus potentially better performing and more optimized devices. The first part of the thesis is focused upon an adhesive wafer-level layer transfer method to fabricate resistive microbolometer-based long-wavelength infrared focal plane arrays. This is realized by a CMOS-compatible transfer of monocrystalline silicon with epitaxially grown silicon-germanium quantum wells. Heterogeneous transfer methods are also used for the realization of filtering devices, integration of distributed small dies onto larger wafer formats and to fabricate a graphene-based pressure sensor. The filtering devices consist of very fragile nano-porous membranes that with the presented dry adhesive methods can be transferred without clogging or breaking. Pick-and-place methods for the massive transfer of small dies between different wafer formats are limited by time and die size-considerations. Our presented solution solves these problems by expanding a die array on a flexible tape, followed by adhesive wafer bonding to a target wafer. Furthermore, a gauge pressure sensor is realized by transferring a graphene monolayer grown on a copper foil to a micromachined target wafer with a silicon oxide interface layer. This device is used to extract the gauge factor of graphene. Adhesive bonding is an enabling technology for the presented heterogeneous integration techniques. A blister test method together with an experimental setup to characterize the bond energies between adhesives and bonded substrates is also presented.QC 20131003
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Jenkins, Colin. "MEMS actuated retroreflective phase modulator". Thesis, University of Strathclyde, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436834.
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Gabbay, Lynn Daniel. "Computer aided macromodeling for MEMS". Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/9955.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.Includes bibliographical references (p. 85-87).
by Lynn Daniel Gabbay.
Ph.D.
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Ramaswamy, Deepak 1974. "Mixed regime simulation in MEMS". Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/46145.
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Cottrell, Jared D. (Jared Desjardins) 1975. "Server architecture for MEMS characterization". Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/47696.
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Thesis (S.B. and M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.Includes bibliographical references (leaves 85-87).
by Jared D. Cottrell.
S.B.and M.Eng.
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Then, Alan M. (Alan Michael) 1965. "Commercialization of microelectromechanical systems (MEMS)". Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8920.
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Thesis (S.M.M.O.T.)--Massachusetts Institute of Technology, Sloan School of Management, Management of Technology Program, 2001.Includes bibliographical references (leaves 69-72).
Microelectromechanical systems (MEMS), at their core are a set of technologies that employ the processes developed in the integrated circuit (IC) and semiconductor industries to construct electro- mechanical devices. In the case of Microopticelectromechanical systems (MOEMS), optical elements are also integrated into these devices. MEMS technology holds the promise of significantly miniaturizing, reducing the cost of, and enhancing the performance of many sensors and actuators, evidence its widespread use in the manufacture of accelerometers, ink jet printer heads and various chemical gas sensors. Despite its stellar success in these "killer-applications," MEMS technology has failed to realize the widespread success many had predicted for it. Nonetheless, this technology has recently been explored extensively for new electro-optics applications, specifically in telecommunications for dense wavelength division multiplexing (DWDM) and optical switching. This thesis examines various models of dynamic technology adoption and explores how they apply to MEMS technology. Furthermore, by way of historical comparison to the development of application specific integrated circuit (ASIC), it will identify various developmental similarities. Finally, a unique model outlining the critical driving forces behind the adoption of MEMS technology will be constructed.
by Alan M. Then.
S.M.M.O.T.
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Ibrahim, Amr. "Remotely interrogated MEMS pressure sensor". Thesis, University of Glasgow, 2012. http://theses.gla.ac.uk/4149/.
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This thesis considers the design and implementation of passive wireless microwave readable pressure sensors on a single chip. Two novel-all passive devices are considered for wireless pressure operation. The first device consists of a tuned circuit operating at 10 GHz fabricated on SiO2 membrane, supported on a silicon wafer. A pressure difference across the membrane causes it to deflect so that a passive resonant circuit detunes. The circuit is remotely interrogated to read off the sensor data. The chip area is 20 mm2 and the membrane area is 2mm2 with thickness of 4 µm. Two on chip passive resonant circuits were investigated: a meandered dipole and a zigzag antenna. Both have a physical length of 4.25 mm. the sensors show a shift in their resonant frequency in response to changing pressure of 10.28-10.27 GHz for the meandered dipole, and 9.61-9.58 GHz for the zigzag antenna. The sensitivities of the meandered dipole and zigzag sensors are 12.5 kHz and 16 kHz mbar, respectively. The second device is a pressure sensor on CMOS chip. The sensing element is capacitor array covering an area of 2 mm2 on a membrane. This sensor is coupled with a dipole antenna operating at 8.77 GHz. The post processing of the CMOS chip is carried out only in three steps, and the sensor on its own shows a sensitivity of 0.47fF/mbar and wireless sensitivity of 27 kHz/mbar. The MIM capacitors on membrane can be used to detune the resonant frequency of an antenna.
41
Haneef, Ibraheem. "SOI CMOS MEMS flow sensors". Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611843.
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42
Li, Li. "MEMS micromirrors for imaging applications". Thesis, University of Strathclyde, 2013. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=19508.
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Optical MEMS (microelectromechanical systems) are widely used in various applications. In this thesis, the design, simulation and characterisation of two optical MEMS devices for imaging applications, a varifocal micromirror and a 2D scanning micromirror, are introduced. Both devices have been fabricated using the commercial Silicon-on-Insulator multi-users MEMS processes (SOIMUMPs), in the 10 m thick Silicon-on-Insulator (SOI) wafer. Optical MEMS device with variable focal length is a critical component for imaging system miniaturisation. In this thesis, a thermally-actuated varifocal micromirror (VFM) with 1-mm-diameter aperture is introduced. The electrothermal actuation through Joule heating of the micromirror suspensions and the optothermal actuation using incident laser power absorption have been demonstrated as well as finite element method (FEM) simulation comparisons. Especially, the optical aberrations produced by this VFM have been statistically quantified to be negligible throughout the actuation range. A compact imaging system incorporating this VFM has been demonstrated with high quality imaging results. MEMS 2D scanners, or scanning micromirrors, are another type of optical MEMS which have been widely investigated for applications such as biomedical microscope imaging, projection, retinal display and optical switches for telecommunication network, etc. For large and fast scanning motions, the actuation scheme to scan a micromirror in two axes, the structural connections and arrangement are fundamental. The microscanner introduced utilises two types of actuators, electrothermal actuators and electrostatic comb-drives, to scan a 1.2-mm-diameter gold coated silicon micromirror in two orthogonal axes. With assistance of FEM software, CoventorWare, the structure optimisation of actuators and flexure connections are presented. The maximum optical scan angles in two axes by each type of actuator individually and by actuating the two at the same time have been characterised experimentally. By programming actuation signals, the microscanner has achieved a rectangular scan pattern with 7°x10° angular-scan-field at a line-scan rate of around 1656 Hz.
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Ferreira, Anderson Henrique Rodrigues 1983. "Análise eletromecânica do giroscópio MEMS". [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263218.
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Orientador: José Maria Campos dos SantosDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
Made available in DSpace on 2018-08-23T14:00:55Z (GMT). No. of bitstreams: 1 Ferreira_AndersonHenriqueRodrigues_M.pdf: 13469668 bytes, checksum: 25f9c2a03e6a62e5d1a871b78053c4b1 (MD5) Previous issue date: 2013
Resumo: Este trabalho apresenta uma análise dos problemas físicos associados ao projeto de um sensor inercial giroscópio baseado na tecnologia MEMS (micro-electro-mechanical-system). O dispositivo oferece uma resposta elétrica na forma de uma variação da capacitância devido à força de Coriolis e como consequência obtém-se uma medida da velocidade angular de um sistema. Uma formulação analítica da dinâmica eletromecânica de um giroscópio com dois graus de liberdade é revista e implementada em um programa MATLAB/Simulink (R2011a) ®, onde são obtidas as respostas em deslocamento nos domínios do tempo e da frequência. Para melhorar a capacidade do projeto de sensores inerciais, uma abordagem da análise eletromecânica do giroscópio usando o Método dos Elementos Finitos (MEF) do programa comercial ANSYS 12.0® é apresentada. Neste contexto, dois projetos de giroscópios MEMS encontrados na literatura (giroscópio de ACAR e de NGUYEN) são analisados. Análises estática, modal e harmônica são realizadas e os resultados comparados com aqueles obtidos com os modelos analíticos. A resposta harmônica para o modelo eletromecânico completo de MEF não foi realizada devido à dificuldade de simular análises harmônicas incluindo os elementos de Atuação e Detecção simultaneamente. Para superar este problema o elemento Detector foi substituído por um elemento de mola. Os resultados obtidos no giroscópio de NGUYEN apresentaram boa concordância entre os modelos. Contudo, os resultados com o giroscópio de ACAR apresentaram erros significativos entre os modelos, os quais são oriundos da geometria usada no modelo de MEF que se mostrou flexível em regiões que deveriam ser rígidas. Uma análise estática de diferentes tipos de suspensão elástica para giroscópios MEMS é apresentada no Apêndice B
Abstract: This paper presents an analysis of the physical problems associated with the design of a gyroscope inertial sensor based on MEMS technology (MicroEletroMechanical System). The device gives a response in the form of an electrical capacitance change due to the Coriolis force and as a result obtains a measure of the angular velocity of a system. Analytical formulation of the electromechanical dynamics of a gyroscope with two degrees of freedom is reviewed and implemented in a MATLAB/Simulink (R2011a) ® code, where the displacement responses are obtained in time and frequency domains. To improve the capacity of the inertial sensors design, another electromechanical gyroscope analysis approach using the Finite Element Method (FEM) of commercial software ANSYS ® 12.0 is presented. In this context, two designs of MEMS gyroscopes from the literature (NGUYEN's and ACAR's gyroscopes) are analyzed. Static, modal and harmonic analysis are performed and the results compared with those obtained with the analytical models. The harmonic response for the complete electromechanical model of MEF was not performed due to the inability to run harmonic analysis including Actuator and Detector elements simultaneously. To overcome this difficulty, the Detector element was replaced by a spring element. The results obtained with NGUYEN's gyroscope showed good agreement between the models. However, the results with the ACAR's gyroscope showed significant errors between the models, which are derived from the geometry used in the FEM model, that was flexible to regions that should be rigid. A static analysis of different types of elastic suspension for MEMS gyroscopes are shown in Appendix B
Mestrado
Mecanica dos Sólidos e Projeto Mecanico
Mestre em Engenharia Mecânica
44
Abadie, André Keller. "Acelerômetro MEMS para navegação inercial". Instituto Tecnológico de Aeronáutica, 2011. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=2002.
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Esta tese apresenta o desenvolvimento de um acelerômetro MEMS para navegação inercial. O projeto teve que aderir e superar as fortes limitações do serviço de fabricação multi-usuário e dos escassos recursos de pós-processamento disponíveis. O elemento sensível usa a topologia de placas paralelas com realimentação de força. A deflexão da massa de prova, decorrente de uma aceleração externa, gera variação diferencial nas capacitâncias do sensor. Essa deflexão é compensada pela aplicação de força eletrostática na massa de prova. O esforço necessário para cancelar a aceleração externa torna-se então a medida do acelerômetro. A eletrônica proposta usa um amplificador de carga em circuito integrado e um circuito externo para realizar a lei de controle e gerar a realimentação de força. O desempenho teórico/simulado é de 40 ug/sqrtHz de ruído mecânico, 100 Hz de largura de banda e 10 g de fundo de escala. Este desempenho é bastante adequado para uso em navegação inercial de diversas aplicações. Foi feito o projeto do sensor MEMS, de blocos da eletrônica integrada e do compensador de realimentação de força. Para testar o conceito do circuito de leitura do sensor, foi projetada e testada uma montagem discreta. O sensor MEMS foi fabricado pelo serviço multi-usuário da MEMSCAP. Uma amostra foi pós-processada no laboratório CCS-Unicamp: foi feita uma corrosão sobre a placa central e posterior wedge bonding para a montagem. A montagem apresentou dificuldades e não foi concluída. Da eletrônica, duas rodadas de microfabricação foram realizadas na austriamicrosystems. A primeira consistiu em circuitos baseados em amplificador operacional, enquanto a segunda foi uma fonte de referência bandgap. Foram realizados os testes de ambos os circuitos integrados, que positivamente verificaram os resultados de simulação.
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Pekárek, Jan. "Katodové nanostruktury v MEMS aplikacích". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217244.
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The main goal of this work is to introduce new carbon structures - carbon nanotubes. The main objective of this work is to take advantage of the unique characteristic of carbon nanotubes to emit electrons at very low supply voltage.
46
SUN, JING. "THREE-DIMENSIONAL MONOLITHIC MEMS COIL". University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1067624824.
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47
Choonee, Kaushal R. V. "MEMS micro-contact printing engines". Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/6868.
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This thesis investigates micro-contact printing (µCP) engines using micro-electro-mechanical systems (MEMS). Such engines are self-contained and do not require further optical alignment and precision manipulation equipment. Hence they provide a low-cost and accessible method of multilevel surface patterning with sub-micron resolution. Applications include the field of biotechnology where the placement of biological ligands at well controlled locations on substrates is often required for biological assays, cell studies and manipulation, or for the fabrication of biosensors. A miniaturised silicon µCP engine is designed and fabricated using a wafer-scale MEMS fabrication process and single level and bi-level µCP are successfully demonstrated. The performance of the engine is fully characterised and two actuation modes, mechanical and electrostatic, are investigated. In addition, a novel method of integrating the stamp material into the MEMS process flow by spray coating is reported. A second µCP engine formed by wafer-scale replica moulding of a polymer is developed to further drive down cost and complexity. This system carries six complementary patterns and allows six-level µCP with a layer-to-layer accuracy of 10 µm over a 5 mm x 5 mm area without the use of external aligning equipment. This is the first such report of aligned multilevel µCP. Lastly, the integration of the replica moulded engine with a hydraulic drive for controlled actuation is investigated. This approach is promising and proof of concept has been provided for single-level patterning.
48
Tsai, Jui-che. "MEMS-based wavelength-selective switches". Diss., Restricted to subscribing institutions, 2005. http://proquest.umi.com/pqdweb?did=888861551&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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49
Albahri, Shehab. "Mechanical characterization of MEMS devices". Diss., Online access via UMI:, 2007.
Znajdź pełny tekst źródła
50
Avila, Gomez Adrian Enrique. "Development MEMS Acoustic Emission Sensors". Scholar Commons, 2017. https://scholarcommons.usf.edu/etd/7392.
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The purpose of this research is to develop MEMS based acoustic emission sensors for structural health monitoring. Acoustic emission (AE) is a well-established nondestructive testing technique that is typically used to monitor for fatigue cracks in structures, leaks in pressurized systems, damages in composite materials or impacts. This technology can offer a precise evaluation of structural conditions and allow identification of imminent failures or minor failures that can be addressed by planned maintenances routines. AE causes a burst of ultrasonic energy that is measured as high frequency surface vibrations (30 kHz to 1 MHz) generated by transient elastic waves that are typically emitted from growing cracks at the interior of the structure.
The AE sensor marketplace is currently dominated by bulky and expensive piezoelectric transducers that are wired to massive multichannel data acquisition systems. These systems are complex to operate with the need of signal conditioning units and near proximity pre-amplifiers for each sensor that demands a fairly complicated wiring requirements. Furthermore, due to the high prices of conventional AE sensors and associated instrumentation, and the current requirements in sensor volumes for smart transportation infrastructure, it is undeniable that new AE technology is required for affordable structural health monitoring. The new AE technology must deliver comparable performance at one or two orders of magnitude lower cost, size and weight. MEMS acoustic emission (AE) sensors technology has the potential to resolve several of these traditional sensor’s shortcomings with the advantage of possible integration of on-chip preamplifier while allowing substantially cost reduction due to the batch processing nature of MEMS technology.
This study will focus on filling some of the major existing gaps between current developments in MEMS acoustic emission sensors and commercial piezoelectric sensors, such as sensor size, signal-to-noise ratio (SNR), cost and the possibility to conform to sharply curved surfaces. Basically, it is proposed to develop a new class of micro-machined AE sensors or sensor arrays through strategic design of capacitive and piezoelectric MEMS sensors, which will focus on optimizing the following performance aspects: Creating geometric designs to manipulate the sensor resonant frequency and to optimize Q factor under atmospheric pressure and ambient environment. Developing a strategic selection of materials according to its acoustic impedance as insulator, structure and backing material. Developing strategies to improve the signal to noise ratio SNR with and without integrated amplification/signal processing. Performing a comparison between MEMS and commercial piezoelectric sensors.