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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
191

Fabrication, caractérisation et application capteur de MEMS organiques à base de microleviers / Fabrication, characterization and sensor application of organic MEMS based on microcantilever structures

Dubourg, Georges 05 November 2012 (has links)
Cette thèse présente la conception de MEMS à base de matériaux organiques et cela, en vue de réaliser des capteurs biochimiques. Dans ces travaux les matériaux organiques ont été proposés en tant qu’alternative au silicium afin, d’une part, de réduire le coût des capteurs biochimiques par le développement de procédés de structuration simples et peu couteux et, d’autre part, car les polymères peuvent être synthétisés de telle sorte à leur conférer des propriétés spécifiques et contrôlables pour une application visée. Dans ces travaux à fort caractère technologique, des méthodes adaptées à la structuration de ce type de matériau ont été développées. Une de ces méthodes consiste à déposer le matériau organique au travers d’un micropochoir fait en SU-8. Cette méthode permet de déposer et de structurer le matériau en une seule étape, d’une part, et d’autre part de mettre en forme des polymères photo et thermosensibles. Une méthode de report inspirée du «  wafer-bonding en SU-8 » a été adaptée pour la fabrication collective de puces de microleviers organiques. Ensuite, un actionnement électromagnétique a été intégré aux structures afin d’améliorer les performances de ces dernières utilisées en tant que résonateur.Et enfin, un concept original de biocapteur de masse basé sur des microleviers monocouches a été développé. Dans ce cas, la couche sensible faite d’un polymère à empreinte moléculaire assure à la fois, la reconnaissance biologique et la transduction de l’effet mécanique du microlevier. / This thesis presents the design of MEMS-based on organic materials to achieve biochemical sensors. In this work, organic materials have been proposed as an alternative to silicon to reduce the cost of biochemical sensors by developing simple and inexpensive processes, and because polymers can be synthesized to give them specific and controllable properties. In this technological work, suitable methods to pattern this type of materials have been developed. One of these methods combines deposition and patterning in one step thanks to spray-coating through polymer microstencils. Then, to obtain collective production of organic chips free-standing microcantilevers from a free structure, wafer-bonding approach based on bonding of two SU-8 layers has been introduced. On the other hand, an electromagnetic actuator has been integrated into the structures to improve the performances of theses structures used as resonators.And finally, an original concept of mass biosensor based on monolayer microcantilevers has been developed. In this case, the sensitive layer made ​​of molecularly imprinted polymer allows the biological detection and the transduction of the mechanical effect.
192

Investigation of Synchronization in a Ring of Coupled MEMS Resonators / リング結合したMEMS共振器の同期に関する研究

Suketu Dilipkumar Naik 26 September 2011 (has links)
Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第16400号 / 工博第3481号 / 新制||工||1526(附属図書館) / 29031 / 京都大学大学院工学研究科電気工学専攻 / (主査)教授 引原 隆士, 教授 田畑 修, 准教授 山田 啓文 / 学位規則第4条第1項該当
193

Skakelmoduskragbron vir plasmatoepassings

Roos, Stefanus Dawid 14 August 2012 (has links)
M.Ing. / 50 Hz technology has led the plasma torch converters up to now. This technology was used. The high power levels of plasma torches made it difficult to implement high frequency technology. At this stage it is possible to use high-frequency technology in plasma torch applications. This thesis implements a high frequency converter suitable for plasma applications. The converter used for this application is the Partial Series Resonant Converter. A study launched to get the properties of plasmas showed that the control method used at this stage namely current control is not the ideal control method. Changing the control method of the converter made it possible to see what influence it has on the plasma. A thorough large signal analisis of the Partial Series Resonant Converter was done. From this analisis a transfer function of the converter was developed and the control parameters were calculated. This control parameters made it possible to change the control and to investigate the different control methods. The design of the plasma torch converter was based on the design of a distributed transformer, input and output filter and a non-linear controller. The results of the Partial Series Resonant Converter showed that power control leads to a more stable plasma. This thesis made a positive contribution to the knowledge of plasma torches and the knowledge of plasma torch converters. The thesis forms a summarry of plasmas and plasma-related topics, and futher study fields are defined by this thesis.
194

Développement de résonateurs hyperfréquences pour la réalisation de capteurs sans puce dédiés à la maintenance prédictive des infrastructures / Development of chipless wireless sensors for the predictive maintenance of infrastructures

Khalifeh, Rania 18 November 2016 (has links)
La corrosion et la dégradation des matériaux sont des problèmes majeurs qui impactent économiquement de nombreux domaines d’activités. Cette dégradation dépend de nombreux paramètres environnementaux. Dans ce cadre, le suivi de la dégradation des matériaux est primordial. L’objectif de cette thèse est donc d’élaborer des capteurs de dégradation de matériaux, sans fils et passifs énergétiquement. Pour cela, notre travail sera basé sur la technologie RFID (Radio Frequency Identification) passive. Nous présentons alors, des résonateurs sensibles à la dégradation et à la corrosion des matériaux. Celles-ci étant souvent liées à la présence d’eau dans le milieu environnant, une partie de la thèse concerne le suivi de l’absorption dans les revêtements organiques et les bétons. Afin de corréler la présence d’eau avec une dégradation du métal présent dans le diélectrique, un résonateur sensible au potentiel de corrosion est ensuite proposé. Pour finir, une étude sur la détection des sels dissouts dans le milieu est réalisée par ce type de technique. Suite à la présentation de ces résultats, une partie plus courte consacrée à la réalisation d’un démonstrateur sur la bande ISM autorisée à 2.45 GHz est présentée. Elle permet une discussion sur l’utilisation de ce type de capteur dans des situations réelles. / Corrosion and material degradation are major problems that economically impact many areas of activity. This degradation depends on many environmental parameters. In this context, monitoring the degradation of materials is crucial. The objective of this thesis is to develop materials degradation sensors that are chipless and wireless. For that purpose, this work will be based on passive RFID (Radio Frequency Identification). We present different resonators sensitive to the degradation and corrosion of materials. These are often linked to the presence of water in the environment; part of the thesis concerns the monitoring of the absorption in organic coatings and concrete. In order to correlate the presence of water with a degradation of the metal present in the dielectric, a resonator sensitive to the corrosion potential is then proposed. Finally, a study on the detection of dissolved salts in the medium is performed by this type of technique. Following these results, a shorter part of the realization of a demonstrator in the authorized ISM band at 2.45 GHz is presented. It provides a discussion about the use of this type of sensor in real situations.
195

Cavity enhanced eigenmode multiplexing for volume holographic data storage

Miller, Bo E., Takashima, Yuzuru 23 August 2017 (has links)
Previously, we proposed and experimentally demonstrated enhanced recording speeds by using a resonant optical cavity to semi-passively increase the reference beam power while recording image bearing holograms. In addition to enhancing the reference beam power the cavity supports the orthogonal reference beam families of its eigenmodes, which can be used as a degree of freedom to multiplex data pages and increase storage densities for volume Holographic Data Storage Systems (HDSS). While keeping the increased recording speed of a cavity enhanced reference arm, image bearing holograms are multiplexed by orthogonal phase code multiplexing via Hermite-Gaussian eigenmodes in a Fe: LiNbO3 medium with a 532 nm laser at two Bragg angles for expedited recording of four multiplexed holograms. We experimentally confirmed write rates are enhanced by an average factor of 1.1, and page crosstalk is about 2.5%. This hybrid multiplexing opens up a pathway to increase storage density while minimizing modifications to current angular multiplexing HDSS.
196

Design And Analysis Of Integrated Optic Resonators For Biosensing Applications

Malathi, S 12 1900 (has links) (PDF)
In this thesis, we have designed and optimized strip waveguide based micro-ring and micro-ring and micro-racetrack resonators for biosensing applications. Silicon-On-Insulator (SOI) platform which offers several advantages over other materials such as Lithium Niobate, Silica on Silicon and Silicon nitride is considered here. High index contrast enables us to miniaturize the biosensor devices and monolithic integration of source and detectors on the same chip. We have considered the dispersive nature of the waveguide and proceeded towards optimization. Finite difference schemes and Finite Difference Time Domain (FDTD) methods are the primary tools used to model the biosensor. Various structures such as channel waveguides and beam structures are analyzed on the basis of their suitability for sensing applications. Strip and Rib waveguides are the two geometries considered in our studies. In an optical guiding structure, effective index of the propagating optical mode can be induced by two different phenomena: i. Homogeneous Sensing In this category, effective index of a propagating optical mode changes with uniformly distributed analytes extending over a distance well exceeding the evanescent field penetration depth. The sample serves as the waveguide cover. ii. Surface Sensing In the case of surface sensing, analytes bound to the surface of the waveguide. The effective index of an optical mode changes with the refractive index as well as the thickness of an adlayer. A thin layer of adsorbed or bound molecules transported from liquid or gaseous medium serving as waveguide cover is referred as an adlayer. Both homogeneous and surface sensing schemes are addresses in this work. By bulk sensing method, the characteristics of bioclad covering the device are studied. Optimization of the resonator structure involves the analysis of following parameters: • Gap between the ring and bus waveguides • Free spectral range • Extinction ratio • Quality factor We have achieved a maximum bulk sensitivity of 115 nm / RIU with ring waveguide width of 450 nm and bus width of 350 nm which is better than an earlier reported value of 70 nm/ RIU. We have proposed a novel detection scheme consisting of a micro-racetrack resonator formed over a cantilever structure. The devoice works on the principle of opto-mechanical coupling to detect conformational changes due to biomolecular adherence. BSA (Bovine Serum Albumin) and IgG ( Immuno Globulin G) are the two proteins considered in the work. Mechanical analysis of the beam for tensile and compressive stresses and corresponding spectral responses of the racetrack resonators are analyzed both by semi-analytical and method and numerical analyzes. We compared various aspects of rib and strip waveguide racetrack resonators. We have proved by numerical simulation, that the device is capable of distinguishing tensile and compressive stress. Two strip waveguides of dimensions : 450 nm X 220 nm and 400 nm X 180 nm, former supporting both Quasi-TE and Quasi-TM modes where as the second configuration allows only Quasi-TE mode alone. Sensitivity of the cantilever sensor is : 0.3196 x 10-3 nm/ µɛ at 1550 nm wavelength.
197

Metamaterial stepped impedance resonator filters for wireless communication systems

Karimian, Shokrollah January 2011 (has links)
This thesis introduces, for the first time, Stepped Impedance Resonator (SIR) bandpass filters (BPF) based on Composite Right/Left-Handed (CRLH) transmission lines. In other words, a novel approach in design of BPFs for RF and microwave applications is successfully proposed and examined, which can serve both miniaturisation and performance enhancement purposes. In conducting this research, design, development and optimisation procedures and techniques for the proposed BPFs have been presented. Theoretical, numerical and experimental results have confirmed that these filters are capable of significantly reducing the size while maintaining the integrity of the filter performance; and in some cases, extensively enhancing the performance.Two λg/4-type CRLH SIRs are designed and characterised based on the available equations. ADS lumped-element equivalent circuit model and HFSS full-wave electromagnetic simulation, and measurement results prove that both CRLH SIRs surpassed their RH counterparts, in terms of both size and performance. Indeed, comparison of the first CRLH SIR with its RH counterpart revealed a 35% size (length) reduction. The second CRLH SIR design is measured to be 66% smaller than its RH counterpart and 14% smaller than the initial CRLH SIR. In addition, simulation and measurement results reveal that an intelligently designed CRLH SIR shows a better quality factor Q and input impedance |Zin| response, and provides higher design flexibility. Phase unwrapping and energy (current) flow analysis have been used to prove left-handedness of the CRLH SIRs. The concept is extended to propose multi-section (λg/2-type and tri-section SIRs) and tunable CRLH SIRs. Numerical analysis and obtained results show that the λg/2-type CRLH SIR benefits from a 45% size (length) reduction compared to its RH counterpart, and a better |Zin| response. The results obtained from the tri-section CRLH SIR (TSSIR), clearly show that the TSSIR is capable of relocating (and minimising) the multiple spurious resonance frequencies, while maintaining the same fundamental frequency f0. As such, no spurious frequency is observed before 8 GHz. Also, measurements indicated that the CRLH TSSIR is not only 30% smaller in length compared to its RH counterpart, it was even 28% smaller than a two-section RH SIR resonating at the same frequency of 2.5 GHz. In addition, the tuning capability of the ferrite CRLH SIR is illustrated when the operating frequency of the resonator is tuned from 5.1 GHz to 5.4 GHz, and 5.65 GHz for H0 = 2000, 2250, and 2500 Oe, respectively.These SIRs are then combined and configured to form two main categories of CRLH SIR bandpass filters: PCB filters based on RT Duroid and MMIC filters based on GaAs. In both filters, the homogeneity condition has been satisfied by ensuring that the longest length is much less than λg (in this case l = λg/12) for PCB-based filters and l = λg/14 for MMIC filters at the centre frequency of the filters. The first PCB-based CRLH SIR filter, which has been designed to operate at 2.75 GHz, is measured 24mm × 28mm. HFSS 3-D full-wave simulations and measurement results of this filter reveal that, with an insertion loss of -2.6dB and return loss of -21.5dB, the filter not only has a very good selectivity, but also is extremely efficient in extending the free-spurious stop-band, pushing the first spurious response to around 11 GHz (about 4×f0). The second PCB-based CRLH SIR filter has much smaller size, measuring overall filter dimensions of 6mm × 5.14mm. This filter also benefits from a smaller resonator size, improved overall coupling and a more controllable circuit. Theory, full-wave simulation and measurement results demonstrate that, with an insertion loss of -1dB and return loss of -34dB, the miniaturised CRLH SIR filter proves very successful as it was about 80% smaller in size compared to its RH counterpart with the same centre frequency, while maintaining the integrity of the filter performance. Moreover, the miniaturised CRLH SIR BPF is significantly more controllable in its dimensions and response due to the fact that more elementary parameters are available in the CRLH configuration.The MMIC CRLH SIR bandpass filters are then proposed with an emphasis on further size reduction with maintenance (or enhancement) of their transmission responses. As such, two classes of MMIC filters were designed: the first one is very small measuring 3.2mm × 3.4mm, with an insertion loss of -5.3dB at the centre frequency 3.1 GHz. The filter also shows good attenuation both before and after the passband with its first spurious frequency occurring at 13.52 GHz (i.e. > 4×f0). The second set of MMIC filters employed multilayer topology to reduce the filter size. It has been clearly shown that with an intelligent design, the size (dimension) limitations of the PCB-based filters have been overcome by using the MMIC technology, resulting in filters with significantly reduced sizes - design I: 1.32mm×3.35mm, and design II: 1.4mm × 1.5mm. It has also been observed that MMIC structures are generally exposed to inevitable losses, though steps can be taken to reduce such losses.
198

Nova etiqueta chipless de RFID com comunicação redundante / New chipless RFID tag with redundant communication

Santos Souza, Gilberto de Tadeu, 1988- 26 August 2018 (has links)
Orientador: Leonardo Lorenzo Bravo Roger / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Tecnologia / Made available in DSpace on 2018-08-26T21:14:03Z (GMT). No. of bitstreams: 1 SantosSouza_GilbertodeTadeu_M.pdf: 4051949 bytes, checksum: 3271a81290629f1d51c661d022a0cbd7 (MD5) Previous issue date: 2015 / Resumo: O projeto e a análise teórico-experimental de uma nova etiqueta sem chip para RFID com comunicação redundante é apresentado. Esta nova etiqueta poderá ser capaz de operar em duas bandas de frequências diferentes para a transmissão da informação binária, aproveitando a utilização em sua concepção de antenas dual-band. A técnica aqui mencionada é clássica, conhecida como diversidade de frequência, mas é utilizada neste trabalho pela primeira vez aplicada em etiquetas chipless de RFID visando aumentar a confiabilidade da comunicação com as leitoras de RFID. Simulações realizadas do novo dispositivo proposto com o software HFSS (High Frequency Structural Simulator) mostraram o seu desempenho adequado. A metodologia do projeto é apresentada passo a passo e os resultados são analisados e discutidos no texto / Abstract: The project and the theoretical-experimental analysis of a new chipless RFID tag with redundant communication is presented. This new tag may be capable to operate in two different frequencies bands for the transmission of binary information, taking advantage of the use in its design of dual-band antennas. The technique mentioned here is classic, known as frequency diversity, but it is used in this work for the first time applied in chipless RFID tags to increase the reliability of the communication with the RFID readers. Simulations of the proposed new device with HFSS (High Frequency Structural Simulator) software showed an adequate performance. The project methodology is presented step by step and the results are analyzed and discussed in the text / Mestrado / Tecnologia e Inovação / Mestre em Tecnologia
199

Apodized Coupled Resonator Optical Waveguides: Theory, design and characterization

Doménech Gómez, José David 23 September 2013 (has links)
In this work we propose the apodization or windowing of the coupling coefficients of the unit cells conforming a coupled resonator device as a mean to reduce the level of secondary sidelobes in the case of SCISSOR configuration [7] or reducing the passband ripples in the case of CROW configuration [8]. This technique is regularly employed in the design of digital filters [18] and has been applied as well in the design of other photonic devices such as corrugated waveguide filters [9] and fiber Bragg gratings [19]. We also propose a novel technique for the apodization of coupled resonator structures by applying a longitudinal offset between resonators in order to modify the power coupling constant, which alleviates the technical requirements required for the production of these devices. We will demonstrate the design, fabrication and characterization of CROW structures employing the apodization through the aforementioned technique. / Doménech Gómez, JD. (2013). Apodized Coupled Resonator Optical Waveguides: Theory, design and characterization [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/32278 / TESIS
200

Ultrafast, CMOS compatible, integrated all optical switching

Matres Abril, Joaquín 09 June 2014 (has links)
El proyecto consistirá en implementar funcionalidades fotónicas avanzadas sobre silicio tales como conmutación ultra rápida o la realización de puertas lógicas todo ópticas. Para ello se emplearán efectos no lineales del silicio basados en el efecto Kerr, producido por el coeficiente no lineal de tercer orden chi(3) .Los dispositivos deberán funcionar al menos a 40Gbps para que sean competitivos con los dispositivos actuales de última generación. También deberán ser compatibles con tecnología CMOS, lo cual es crucial para que la fabricación se pueda realizar a gran escala a precios competitivos. / Matres Abril, J. (2014). Ultrafast, CMOS compatible, integrated all optical switching [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/37984 / TESIS

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