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Fabrication of suspended plate MEMS resonator by micro-masonry / Fabrication de nanoplaques résonantes à l'aide de la micro-maçonnerieBhaswara, Adhitya 25 November 2015 (has links)
L'impression par transfert, une technique utilisée pour transférer divers matériaux tels que des molécules d'ADN, de la résine photosensible ou des nanofils semi-conducteurs, s'est dernièrement révélée utile pour la réalisation de structures de silicium statiques sous le nom de micro-maçonnerie. L'étude présentée ici explore le potentiel de la technique de micro-maçonnerie pour la fabrication de résonateurs MEMS. Dans ce but, des microplaques de silicium ont été transférées sur des couches d'oxyde avec cavités intégrées à l'aide de timbres de polymère afin de créer des structures de type plaques suspendues. Le comportement dynamique de ces structures passives a été étudié sous pression atmosphérique et sous vide en utilisant une excitation externe par pastille piézo-électrique mais aussi le bruit thermomécanique. Par la suite, des résonateurs MEMS actifs, à actionnement électrostatique et détection capacitive intégrés, ont été fabriqués en utilisant des étapes supplémentaires de fabrication après impression. Ces dispositifs ont été caractérisés sous pression atmosphérique. Les facteurs de qualité intrinsèques des dispositifs fabriqués ont été évalués à 3000, ce qui est suffisant pour les applications de mesure à pression atmosphérique et en milieu liquide. Nous avons démontré que, puisque l'adhérence entre la plaque et l'oxyde est suffisamment forte pour empêcher une diaphonie mécanique entre les différentes cavités d'une même base, plusieurs résonateurs peuvent être facilement réalisés en une seule étape d'impression. Ce travail de thèse montre que la micro-maçonnerie est une technique simple et efficace pour la réalisation de résonateurs MEMS actifs de type plaque à cavité scellée. / Lately, transfer printing, a technique that is used to transfer diverse materials such as DNA molecules, photoresist, or semiconductor nanowires, has been proven useful for the fabrication of various static silicon structures under the name micro-masonry. The present study explores the suitability of the micro-masonry technique to fabricate MEMS resonators. To this aim, silicon microplates were transfer-printed by microtip polymer stamps onto dedicated oxide bases with integrated cavities in order to create suspended plate structures. The dynamic behavior of fabricated passive structures was studied under atmospheric pressure and vacuum using both external piezo-actuation and thermomechanical noise. Then, active MEMS resonators with integrated electrostatic actuation and capacitive sensing were fabricated using additional post-processing steps. These devices were fully characterized under atmospheric pressure. The intrinsic Q factor of fabricated devices is in the range of 3000, which is sufficient for practical sensing applications in atmospheric pressure and liquid. We have demonstrated that since the bonding between the plate and the device is rigid enough to prevent mechanical crosstalk between different cavities in the same base, multiple resonators can be conveniently realized in a single printing step. This thesis work shows that micro-masonry is a powerful technique for the simple fabrication of sealed MEMS plate resonators.
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Využití interferometrie v VT UHV SPM / Application of Interferometry in VT UHV SPMŠulc, Dalibor January 2015 (has links)
The thesis is aimed at the development of Scanning Probe Microscopes (SPM). It describes design and development of modular controll electronics to be applied eectively on more microscopes SPM. Control electronics consist of stabilized power source, high–voltage amplier and probe signal amplier. The open–source project GXSM has been introduced. It contains a logic control unit which controls scanning, acquiring data and feedback control. GXSM provides a graphical user interface based on linux operation system. Second part of the thesis is aimed at design and development of interferometric deection sensing system for SPM cantilevers and applications at SPM in general. Designed interferometer has been assembled and tested. It can clearly distinguish a signal of amplitude 2 nm. At the end of the thesis the design of interferometric system implementation is presented.
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Synthetic Aperture Radar Interferometry Time-series for Surface Displacement Monitoring: Data interpretation and improvement in accuracy / 干渉SAR時系列解析を用いた地表変動モニタリング: 解析結果の解釈および精度の向上Ishitsuka, Kazuya 23 March 2015 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18937号 / 工博第3979号 / 新制||工||1613(附属図書館) / 31888 / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 松岡 俊文, 教授 田村 正行, 教授 小池 克明 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
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Development, Deployment, and Characterization of a Ku-band InterferometerSwochak, Anthony 01 January 2011 (has links) (PDF)
Space-borne radar interferometry provides a global vantage point to understand climate change, global weather phenomenon, and other Earth dynamics. For climate change observations, space-borne interferometers can be utilized to relate ocean topography to temperature, thus providing a global map of ocean temperatures. Since the oceans are in constant motion, a single-pass interferometer is needed to successfully make these measurements of ocean height. The feasibility of a single-pass measurement is dependent on the physical size of the instrument, hence it is cheaper and more practical to launch a small, light weight instrument into space. Since instrument size scales inversely with operating frequency, high frequency microwave technology (Ku-band and Ka-band) is preferred for these types of applications. However, space-borne deployments become more difficult to implement at these frequencies since the physical structure of the instrument changes in the harsh environment of space. For that reason, a ground-based Ku-band (13.245GHz) radar interferometer has been developed at the University of Massachusetts, Amherst Microwave Remote Sensing Laboratory (MIRSL). In this thesis, a description of the radar hardware as well as interferometric results from Mount Sugarloaf provide a measure of the performance of the radar and demonstrate the capabilities of using a ground-based interferometer as a test-bed for space-borne applications.
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Design and Development of a Ka-band Interferometer for Cryospheric ApplicationsVedantham, Harish K 01 January 2009 (has links) (PDF)
Topographic maps of the earth are essential to geographic and earth science studies. In particular, mapping and estimating physical parameters of the earth’s water and ice cover are critical to global climate studies. Among these, snow, ocean and fresh water topography, snow wetness and water equivalent are of immediate interest to the scientific community.
Challenges in the instrument development and deployment posed by these required measurements are twofold. Firstly, these measurements are required to have global coverage, yet maintain stringent spatial resolution and accuracy margins. Secondly, snow topography measurement requires minimal electromagnetic wave penetration through snow, hence requiring the use of millimeter-wave frequency radars. While having the advantage of smaller and lighter structures, instruments at millimeter-wave frequencies are difficult to design, evaluate and deploy due to their mechanical and electric precision requirements.
This thesis presents the design, development, detailed evaluation and first deployment of a Ka-band interferometer. An overview of the theory of interferometric mapping is presented including a discussion on instrument sensitivity and accuracy. Based in this theory, a geometric and hardware configuration for a rooftop deployment is arrived at. Detailed design and evaluation of the radar receiver is documented. Lastly first results from a rooftop and ground-based deployment are presented.
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Advanced Processing Techniques and Applications of Synthetic Aperture Radar InterferometryMestre-Quereda, Alejandro 06 September 2019 (has links)
Synthetic Aperture Radar interferometry (InSAR) is a powerful and established technique, which is based on exploiting the phase difference between pairs of SAR images, and which aims to measure changes in the Earth’s surface. The quality of the interferometric phase is therefore the most crucial factor for deriving reliable products by means of this technique. Unfortunately, the quality of the phase is often degraded due to multiple decorrelation factors, such as the geometrical or temporal decorrelation. Accordingly, central to this PhD thesis is the development of advanced processing techniques and algorithms to extensively reduce such disturbing effects caused by decorrelation. These new techniques include an improved range spectral filter which fully utilizes an external Digital Elevation Model (DEM) to reduce geometrical decorrelation between pairs of SAR images, especially in areas strongly influenced by topography where conventional methods are limited; an improved filter for the final interferometric phase the goal of which is to remove any remaining noise (for instance, noise caused by temporal decorrelation) while, simultaneously, phase details are appropriately preserved; and polarimetric optimization algorithms which also try to enhance the quality of the phase by exploring all the polarization diversity. Moreover, the exploitation of InSAR data for crop type mapping has also been evaluated in this thesis. Specifically, we have tested if the multitemporal interferometric coherence is a valuable feature which can be used as input to a machine learning algorithm to generate thematic maps of crop types. We have shown that InSAR data are sensitive to the temporal evolution of crops, and, hence, they constitute an alternative or a complement to conventional radiometric, SAR-based, classifications.
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Motion Compensation of Interferometric Synthetic Aperture RadarDuncan, David P. 07 July 2004 (has links) (PDF)
Deviations from a nominal, straight-line flight path of a synthetic aperture radar (SAR) lead to inaccurate and defocused radar images. This thesis is an investigation into the improvement of the motion compensation algorithm created for the BYU inteferometric synthetic aperture radar, YINSAR. The existing BYU SAR processing algorithm produces improved radar imagery but does not fully account for variations in attitude (roll, pitch, yaw) and does not function well with large position deviations. Results in this thesis demonstrate that a higher order motion compensation algorithm is not as effective as using a segmented reference track, coupled with the current lower-order motion compensation algorithm. Attitude variations cause a Doppler shift and are corrected by limiting the processed azimuth bandwidth or by reversing the frequency shift with a range-dependent filter. Another important area considered is the effects of motion compensation on interferometry. When performing interferometry with YINSAR, motion compensating both channels to a single track has two effects. First, the applied MOCO phase corrections remove the "flat-earth" differential phase from the interferogram. Second, range resampling coregisters the two images. All of these changes have helped to improve YINSAR imagery.
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Measurement of Plasma Density in a Gas-Filled Ionizing Laser FocusHeilmann, Nathan Edward 17 February 2012 (has links) (PDF)
We use an interferometric method for measuring the plasma density in a laser-induced plasma as a function of time. Any changes in the density within 5 ns of generation is due plasma expansion and not recombination. The analytic solution for plasma expansion derived for ultracold Neutral Plasmas describes the expansion of our laser produced Neon plasma of densities up to approximately 40 Torr. A model for the utlracold neutral plasmas, in comparison with measurements of our plasmas, can be used to extract an electron temperature. Currently our plasmas have shown to have an electron temperature of approximately 44 eV.
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Interferometry-based Free Space Communication And Information ProcessingArain, Muzamil Arshad 01 January 2005 (has links)
This dissertation studies, analyzes, and experimentally demonstrates the innovative use of interference phenomenon in the field of opto-electronic information processing and optical communications. A number of optical systems using interferometric techniques both in the optical and the electronic domains has been demonstrated in the filed of signal transmission and processing, optical metrology, defense, and physical sensors. Specifically it has been shown that the interference of waves in the form of holography can be exploited to realize a novel optical scanner called Code Multiplexed Optical Scanner (C-MOS). The C-MOS features large aperture, wide scan angles, 3-D beam control, no moving parts, and high beam scanning resolution. A C-MOS based free space optical transceiver for bi-directional communication has also been experimentally demonstrated. For high speed, large bandwidth, and high frequency operation, an optically implemented reconfigurable RF transversal filter design is presented that implements wide range of filtering algorithms. A number of techniques using heterodyne interferometry via acousto-optic device for optical path length measurements have been described. Finally, a whole new class of interferometric sensors for optical metrology and sensing applications is presented. A non-traditional interferometric output signal processing scheme has been developed. Applications include, for example, temperature sensors for harsh environments for a wide temperature range from room temperature to 1000 degree C.
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A Linear Multiplexed Electrospray Thin Film Deposition SystemLojewski, Brandon 01 January 2013 (has links)
Liquid spray is essential to industries requiring processes such as spray coating, spray drying, spray pyrolysis, or spray cooling. This thesis reports the design, fabrication, and characterization of a thin film deposition system which utilizes a linear multiplexed electrospray (LINES) atomizer. First, a thorough review of the advantages and limitations of prior multiplexed electrospray systems leads to discussion of the design rationale for this work. Next, the line of charge model was extended to prescribe the operating conditions for the experiments and to estimate the spray profile. The spray profile was then simulated using a Lagrangian model and solved using a desktop supercomputer based on Graphics Processing Units (GPUs). The simulation was extended to estimate the droplet number density flux during deposition. Pure ethanol was electrosprayed in the cone-jet mode from a 51-nozzle aluminum LINES atomizer with less than 3% relative standard deviation in the D10 average droplet diameter as characterized using Phase Doppler Interferometry (PDI). Finally a 25-nozzle LINES was integrated into a thin film deposition system with a heated, motion controlled stage, to deposit TiO2 thin films onto silicon wafers from an ethanol based nanoparticle suspension. The resulting deposition pattern was analyzed using SEM, optical profilometry, and macro photography and compared with the numerical simulation results. The LINES tool developed here is a step forward to enabling the power of electrospray for industrial manufacturing applications in clean energy, health care, and electronics
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