Dissertations / Theses: 'Dielectric filter'

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Chandran, Ashwin. "Self-Assembled Multilayered Dielectric Spectral Filters." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/30859.

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Thin film optical filters are made by depositing thin films of optical materials on a substrate in such a way as to produce the required optical and mechanical properties. The Electrostatic Self Assembly (ESA) process is accomplished by the alternate adsorption of poly-anionic and poly-cationic molecules on progressive oppositely charged surfaces. This technique offers several advantages such as ease of fabrication, molecular level uniformity, stable multilayer synthesis and avoidance of the need for a vacuum environment. The ESA process offers an excellent choice for manufacturing optical thin film coatings due to its capability to incorporate multiple properties into films at the molecular level and its ability to be a fast and inexpensive process. The ESA process, as a method for manufacturing optical thin film filters has been investigated in detail in this thesis. A specific design was made and analyzed using TFCalc, a commercial thin film design software. Sensitivity analysis detailing the changes in filter response to errors in thickness and refractive index produced by the ESA process were done. These proved that with a high level of quality control, highly reliable and accurate optical thin films can be made by the ESA process.
Master of Science

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Fox, Andrew John. "Invasive varactor tuning of a dielectric resonator." Thesis, Leeds Beckett University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297492.

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Guerrero, Enriquez Rubén Dario. "Etude des filtres miniatures LTCC High K en bandes L&S." Thesis, Brest, 2016. http://www.theses.fr/2016BRES0036/document.

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Dans les systèmes actuels de communication, qu’ils soient terrestre ou spatial, qu’ils soient mobile ou fixe, il y a un réel intérêt à développer des front-ends radiofréquences et hyperfréquences miniatures et performants. Ceci s’applique en particulier aux dispositifs de filtrage où l’encombrement et les facteurs de qualité sont clairement antagonistes. Pour les bandes de fréquences basses aux alentours du GHz, les longueurs d’onde restent encore importantes, rendant difficiles les efforts de miniaturisation. D’autre part il faut aussi s’assurer que ces filtres viendront s’interconnecter aisément avec les autres composants du système, notamment les actifs.Pour toutes ces raisons, le développement de structures de filtres multicouches utilisant des substrats à haute permittivité (εr = 68) selon une approche LTCC apparait comme une alternative intéressante. Elle peut en effet conduire à une réduction significative de l'empreinte (footprint) sans pour autant trop nuire aux performances électriques.Dans le cadre de ce travail, deux structures de filtres multicouches ont été développées pour répondre à des spécifications proposées en bandes L et S, par un équipementier du spatial. Ces filtres ont pour caractéristiques principales un haut niveau de rejection et des faibles pertes dans la bande passante. Pour atteindre les spécifications, un filtre SIW empilé verticalement et un filtre à stubs en court-circuit en configuration triplaque ont été étudiés. Le filtre SIW se distingue par un facteur de qualité élevé, ce qui entraîne des faibles pertes d’insertion et une bonne platitude. La solution à stub permet quant à elle de réduire l’encombrement mais au prix d’un impact sur les performances électriques. Dans les deux cas on tire parti de la souplesse offerte par la technologie LTCC, puisqu’elle offre finalement un degré de liberté supplémentaire, par rapport à une approche planaire classique. Si dans le cas SIW, c’est surtout l’architecture topologique qui a été étudiée finement pour pouvoir agencer et coupler douze cavités, dans le cas du filtre à stub une synthèse mettant à profit tous les degrés de liberté offerts a été spécifiquement développée.Compte tenu de la complexité des filtres, notamment à cause de l’ordre élevé et de la mise en oeuvre de murs « électriques » à partir d’arrangements de via spécifiques, une attention particulière doit être apportée lors des phases de simulation et d’optimisation. De plus la très forte permittivité du substrat ne permet pas d’utiliser de ligne 50 Ohms. Enfin les transitions constituent un point dur de l’exercice surtout dans le cas SIW.Cette thèse co-financée par le CNES (Centre National d'Etudes Spatiales) et Thales Alenia Space, était accompagnée par un projet R&T financé par le CNES. Le fondeur allemand Via Electronic avait en charge la fabrication des filtres
In current communication systems, whether terrestrial or spatial, whether fixed or mobile, there is a real interest in developing high performance miniature RF front-ends. This is applied in particular to filter devices, in which the size and the quality factors are clearly in conflict. For low frequency bands around the GHz, the wavelengths remain significant, making it difficult the miniaturization efforts. On the other hand, we must also ensure that these filters will be easily interconnected with other other system components, including active devices.For all these reasons, the development of multilayer filter structures using high permittivity substrates (Er = 68) in an LTCC approach is consolidated as an interesting alternative. It may lead to a significant footprint reduction without decreasing the electrical performances.As part of this work, two multilayer filter structures have been developed to meet the given specifications in L and S bands, given by a space manufacturer. These filters have as main features a high rejection level and low losses in the passband. To meet the specifications, a vertically stacked SIW filter and a short-circuited stubs filter in a stripline configuration were studied. The SIW filter is characterized by a high quality factor, which results in low insertion loss and good flatness. The stubs filter allows in contrast to reduce the footprint but at the price of impacting the electrical performance. In both cases we take advantage of the flexibility offered by the LTCC technology as it finally provides an additional freedom degree compared to a conventional planar approach. For the SIW filter, the topological architecture was studied and designed in detail, to be able to arrange and synthetize couplings between twelve cavities. In a similar way, for the stub filter a synthesis that takes profit of all the offered freedom degrees was developed.Given the filters complexity, especially due to the high order and the implementation of “electrical walls" based on specific vias patterns, a close attention must be paid during the simulation and optimization phase. In addition, the high permittivity substrate does not allow to conceive 50-Ohms lines. Finally, access transitions constitute a challenging task, especially for the SIW case.This thesis was co-funded by CNES (Centre National d'Etudes Spatiales) and Thales Alenia Space, and was accompanied by an R&T project funded by CNES. The German foundry Via Electronic was responsible for the filters fabrication

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Lazraq, Byström Joseph. "Characterization of Magneto-Dielectric Materials for Microwave Devices." Thesis, Uppsala universitet, Fasta tillståndets elektronik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-419515.

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There is an increasing interest in using new composite materials in microwave devices, to reduce size and weight while maintaining similar performances. A new promising material group is named magneto-dielectric materials, which have the permittivity and permeability values both larger than one. Compared to the commercially used dielectric materials, magneto-dielectric materials can achieve a larger miniaturization factor with the equivalent properties as dielectric materials. There is a very limited availability of commercial magneto-dielectric materials. A recent addition was from Rogers Corporation with MAGTREX 555, [1], that is available as a printed circuit board laminate. The material is limited to 500 MHz operational frequency due to its increased magnetic and dielectric losses. In this thesis the purpose is to understand the loss mechanisms, characterize and understand the state-of-the-art magneto-dielectric materials at microwaves, and to produce a magneto-dielectric material in the lab to understand the material better. A new material was developed with magneto-dielectric properties. The material was based on a polymer base of polystyrene that serves as a dielectric material and doped with nickel nanoparticles that produce the magnetic properties. The contents of the nanoparticles in the mix is a design variable. Nickel-polystyrene samples with different nickel contents of 0%, 2.3% and 4.5%, were produced in the lab and measured in-house to understand the loss mechanism and RF performance.

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Abdolvand, Reza. "Thin-film piezoelectric-on-substrate resonators and narrowband filters." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/28113.

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Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008.
Committee Chair: Farrokh Ayazi; Committee Member: James D. Meindl; Committee Member: John D. Cressler; Committee Member: Nazanin Bassiri-Gharb; Committee Member: Oliver Brand.

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Marchives, Yoann. "Development of 3D filter made by stereolithography." Thesis, Limoges, 2016. http://www.theses.fr/2016LIMO0073/document.

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Les télécommunications sont devenus indispensables dans notre monde actuel. De plus, le volume des données échangées ne cesse de croître. En effet, nous pouvons transmettre nos photos, nos vidéos au monde entier. Nonobstant, nous ne voulons pas attendre pour les avoir, ce qui exige un débit de données très important et par conséquent des signaux avec des bandes passantes plus larges. Les satellites de télécommunications doivent donc s’adapter, c'est pourquoi nous proposons dans ces travaux la recherche de filtre à large bande avec une recherche de compacité et de faibles pertes. Nous nous sommes intéressés à l'utilisation de matériaux céramiques qui permettent d'obtenir de bonnes performances vis à vis de nos besoins. Notre travail est aussi rendu possible par le développement de procédés de fabrication additifs, comme par exemple la stéréolithographie, qui va nous permettre de nous affranchir fortement de règles de dessin contraignantes que nous pourrions avoir en utilisant des procédés classiques. Nous avons développé des filtres avec de larges bandes passantes autour de 4GHz. Une première étude nous a permis de rechercher des concepts qui permettent d'obtenir de forts couplages, conditions sine qua non pour réaliser ces filtres. Plusieurs concepts sont présentés ainsi que leur fabrication et leur mesures. Nous avons ainsi démontré expérimentalement que les concepts proposés, à base de pièces monoblocs céramiques, sont capables de produire des filtres à bandes passantes supérieures à 60 % (voire même 110 % pour une version améliorée)
Every day, the data exchanges increase thanks to the new technologies. We can keep our files, our pictures, our videos online to have an access anywhere on the planet (for now). In this way, the data output of the telecommunication systems has to be increased in order to satisfy the more and more demanding users. One way to allow this is to increase the bandwidths of the different signals, making possible to transmit more data at the same time. In this work, we will develop wide bandpass filters dedicated to space telecommunications. For that purpose, we need them to be compact, with low insertion loss and a limited number of parts to assemble. Consequently, we are interested to use resonators made with ceramic materials that permits to reach such properties. Moreover, these materials are compatible with stereolithography, an additive manufacturing process. Such technology is here very useful for our purpose since its design freedom allows the creation of almost all kind of geometries. To realize such wide bandpass filters, we need strong couplings between the different resonators and also for the accesses, so we will present our studies focused on reaching these specific objectives. Then, we will present different designs of wide bandpass filter around 4GHz. After different generation of ceramic based components, we are be able to experimentally create a 60% bandwidth (even 100% for our last version) very compact bandpass filter filling the objectives of this PhD thesis

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Moradi, Bahareh. "High dielectric permittivity materials in the development of resonators suitable for metamaterial and passive filter devices at microwave frequencies." Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/384854.

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Los metamateriales (MTMs) representan una interesante área de investigación emergente que promete lograr un importante progreso tecnológico y científico en diversas áreas como las telecomunicaciones, la microelectrónica, radar, e imágenes médicas. La cantidad de artículos dedicados a la investigación en esta área (MTMs) se mantiene en pleno crecimiento en la actualidad. Las estructuras MTMs pueden sostener una fuerte resonancia electromagnética con longitudes de onda electricamente pequeñas y por lo tanto son potencialmente aplicables para la miniaturización de los componentes. La miniaturización, optimización del rendimiento del dispositivo mediante la eliminación de frecuencias espurias, y la posibilidad de controlar el ancho de banda del filtro para amplios márgenes de frecuencias es un reto para los presentes y futuros dispositivos de comunicación. Esta tesis se focaliza en el estudio de ambos temas (MTMs y miniaturización) centrándose en las nuevas estrategias para la miniaturización de componentes basados en MTMs. Desde la aparición de estos, los resonadores dieléctricos (DR) son un nuevo tipo de MTMs distinguidos por sus pequeñas pérdidas, así como su fácil combinación con estructuras externas; son la elección adecuada para todo proceso de desarrollo. La principal ventaja de utilizar una alta constante dieléctrica como DR es miniaturizar el tamaño del filtro. El tamaño del filtro de DR es considerablemente menor que la dimensión de la guía de ondas de otros filtros que operan a la misma frecuencia. Dada una constante dieléctrica, tanto la frecuencia de resonancia como el factor de calidad Q se definen a partir de las dimensiones del resonador dieléctrico. Cuanto mayor es la constante dieléctrica, menor es el espacio en el que se concentran los campos, y por lo tanto las dimensiones necesarias para trabajar a una frecuencia de operación definida quedan reducidas. Con el objetivo de miniaturizar las dimensiones del dispositivo, en este trabajo se propone un nuevo diseño para un filtro rechaza banda basado en la alta constante dieléctrica que proporciona una fina capa de pasta epoxy (TFDR) como material DRs excitado a través de una línea microstrip. Además, se propone un filtro pasa banda diseñado en base a los resonadores dieléctricos incrustados (EDR), esto constituye un nuevo enfoque en el campo de los resonadores miniaturizados adaptado a los metamateriales, logrando evitar la degradación del factor Q inherente al coeficiente de acoplamiento basado en partículas eléctricamente pequeñas. En esta tesis se propone también un nuevo filtro pasa de banda basado en resonadores de anillo dividido (SRRs), que es uno de los bloques de construcción MTMs más popular hoy en día. Los filtros de paso de banda basados en este concepto resultan prometedores para las aplicaciones donde la miniaturización y la compatibilidad con la tecnología de ondas planares milimétricas son los requisitos críticos del diseño. Además, para mayor miniaturización, tecnología DR de incrustado es reportada. Otro enfoque para la reducción de tamaño se basa en modificar el resonador tradicional para generar modos adicionales, los cuales hacen que el resonador se comporte como un resonador multimodal. Por último, se propone un filtro compacto paso banda de banda ultra ancha (UWB) utilizando un resonador de anillo abierto conectado a tierra empleado como un resonador multimodal (MMR). Esta propuesta permite utilizar cinco resonancias para producir un ancho de banda fraccional del 128% dentro de la banda ultra ancha. Para demostrar y validar la funcionalidad de los diseños, todos los dispositivos propuestos se han implementado y fabricado, con una excelente concordancia entre las simulaciones y las medidas experimentales. A través de estos métodos ha quedado demostrado que los modelos de sus circuitos equivalentes proporcionan una descripción precisa del comportamiento de las estructuras. En este trabajo se ha conseguido relacionar una relación directa entre las dimensiones físicas del dispositivo y su modelo equivalente eléctrico en forma de circuito.
Metamaterials (MTMs) represent an exciting emerging research area that promises to bring about important technological and scientific advancement in various areas such as telecommunication, radar, microelectronic, and medical imaging. The amount of research on this MTMs area has grown extremely quickly in this time. MTM structure are able to sustain strong sub-wavelength electromagnetic resonance and thus potentially applicable for component miniaturization. Miniaturization, optimization of device performance through elimination of spurious frequencies, and possibility to control filter bandwidth over wide margins are challenges of present and future communication devices. This thesis is focused on the study of both interesting subject (MTMs and miniaturization) which is new miniaturization strategies for MTMs component. Since, the dielectric resonators (DR) are new type of MTMs distinguished by small dissipative losses as well as convenient conjugation with external structures; they are suitable choice for development process. The primary advantage in using a high dielectric constant as a DR is to miniaturize the filter size. The size of DR filter is considerably smaller than the dimension of waveguide filters operate at the same frequency. For a given dielectric constant, both resonant frequency and Q-factor are defined according to the dielectric resonator dimensions. That, the higher the dielectric constant, the smaller the space within which the fields are concentrated, the lower the dimension at a defined frequency. To obtain the required compact sizes new stop-band filter is proposed in this work based on number of thick film high dielectric constant epoxy paste (TFDR) as DRs which excited with a microstrip line. In addition, a band-pass filter is proposed based on embedded dielectric resonators (EDR) constitutes a new approach to the miniaturized resonators suitable for metamaterials design without the Q degradation inherent to the coupling coefficient based on sub-wavelength particles. Also this thesis is proposed a new band-pass filter based on split ring resonators (SRRs), which is a one of the popular MTMs building blocks today. The band-pass filters based on this concept can be very promising for the applications where miniaturization and compatibility with planar millimeter wave technology are the important issues. Also, for further miniaturization, embedded DR technology is reported. Another approach for size reduction is modifying the traditional resonator to generate additional modes, which make the resonator to behave as a multimode resonator. Finally a compact ultra-wide band-pass (UWB) band-pass filter using grounded open ring resonator as a multimode resonator (MMR) is proposed. The approach allows using five resonances to produce a 128% fractional bandwidth into the ultra-wide band. A general theoretic framework has been established using transmission matrix description of the filter constituent components. To demonstrate and validate designs functionality, all the proposed devices are implemented and fabricated, which a good agreement between simulations and measurement are obtained. Through these methods it is demonstrated that their equivalent circuit models provide an accurate description of the considered structures. Indeed, a clear relationship between their equivalents circuit model and the layout physical dimensions were found.

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Jolly, Nicolas. "Filtres accordables volumiques à forts facteurs de qualité pour des applications spatiales." Thesis, Limoges, 2015. http://www.theses.fr/2015LIMO0103/document.

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A l'heure où la demande en quantité d'informations et le nombre d'utilisateurs explosent, toujours avec des limitations en allocation en fréquence et bande passante, les systèmes de télécommunication tendent à optimiser la gestion de leur capacité en s'orientant vers des systèmes reconfigurables. Dans le cas des filtres d'OMUX, apporter de l'accordabilité en conservant d'excellentes performances électriques, thermiques et mécaniques soulève de nombreuses difficultés.Nous avons dans un premier temps démontré la faisabilité sur un filtre à saut de canal à bande passante constante par le biais d'une cavité métallique chargée par un perturbateur en alumine en mouvement de rotation. Ensuite, nous avons proposé des solutions pour avoir un contrôle de la fréquence et de la bande passante en se basant sur la translation de matériaux diélectriques. Les facteurs de qualité mis en jeu sont de l'ordre de la dizaine de milliers. Enfin nous avons tiré profit de l'évolution des technologies d'impression plastique 3D pour valider différents concepts de filtres accordables
At a time when the amount of information and the number of users go through the roof in telecommunication market, the telecommunication systems tend to improve the management of their capacity by moving toward reconfigurable RF devices. However frequency and bandwidth allocated are still restricted. Regarding tunable OMUX filters, the actuation systems generally degrade the overall performances of the device and raise questions in terms of mechanic and thermic.We first demonstrated the feasability of a two state filter with constant narrowband, using a dielectric material (alumina) in rotation inside a metallic housing. Then, we suggested solutions to control both frequency and bandwidth with the translation of a ceramics. We deal with quality factor in the range of ten of thousands for these applications. Eventually, we validated some principle for tunable filters thanks to the efficiency of 3D plastic printer

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Luo, Zhaoju. "Linear Optical Thin Films Formed by Electrostatic Self-Assembly." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/10168.

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The Electrostatic Self-Assembly (ESA) technique possesses great advantages over traditional thin film fabrication methods, making it an excellent choice for a number of applications in the fields of linear and nonlinear optics, electronics, sensing and surface coatings. The feasibility of fabricating linear optical interference filters by ESA methods is demonstrated in this thesis work. Basic single-anion/single-cation ESA films are synthesized and their optical parameters -- refractive index and average thickness for individual bilayer -- are investigated to provide a basis for the in-depth design of optical filters. High performance dielectric stack filters and narrowband and wideband antireflection coatings are designed using TFCalc simulation software and are fabricated by ESA. Both bulk film sensitivity and layer sensitivity to manufacturing errors are provided. The significant agreement between simulation and experiment demonstrates the strong capability of ESA to precisely control the refractive index and produce excellent thin film filters. The performance of optical thin film filters is largely enhanced compared to the results of previous methods. The experiment results indicate that the ESA process may be used to fabricate optical filters and other optical structures that require precise index profile control.
Master of Science

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Malek, Abadi Seyed Ali. "Solutions et matériaux nouveaux pour guide d'onde Térahertz." Thèse, Université de Sherbrooke, 2014. http://hdl.handle.net/11143/5914.

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Dans cette thèse, une étude approfondie sur des matériaux et des solutions pratiques est réalisée afin de répondre aux difficultés rencontrées dans la propagation des ondes à des fréquences térahertz (THz). Deux matériaux ont été identifiés comme étant prometteur: le graphène et le silicium à haute résistivité (HR-Si). Une première solution, basée sur des guides d’ondes à plaques parallèles (parallel plate waveguide-PPWG) avec des conditions de fermetures conducteur parfait (perfect electric conductor-PEC) -- graphène et graphène -- graphène a été analysée dans un premier temps. En considérant l'excitation du graphène par un champ électrique seulement, puis par un champ électromagnétique statique, les équations de Maxwell ont été résolues sous ces deux conditions et les constantes de propagations des différents modes ont été extraites. La démonstration de l'existence d'un mode propagatif hybride à l'intérieur du guide est faite dès que le graphène est excité par un champ magnétique. De plus, il est montré que l'intensité de chaque type de modes, transverse électrique (TE) ou transverse magnétique (TM), peut être ajustée suivant les champs d'excitation du graphène. Bien que le guide à plaques parallèles utilisant du graphène permette d'avoir des propriétés agiles, soit le contrôle des modes selon l'excitation du graphène, il n'en reste pas moins vrai que la faible conductivité intrinsèque au graphène conduit à un problème d'atténuation importante de l'onde. De plus, la difficulté d'obtenir des couches de graphène de taille adéquate entrave le développement de composants et de circuits fonctionnels, utilisables et à un coût raisonnable. La thèse porte ensuite sur l’étude du silicium haute résistivité pour guider des ondes aux fréquences térahertz. Tout d’abord, un guide composé d'une couche de HR-Si, de section rectangulaire dont la largeur est très grande par rapport à la hauteur, est caractérisé en utilisant un système de spectroscopie dans le domaine du temps, système permettant d'obtenir un large spectre de fréquences dans le domaine THz. Par cette caractérisation, les faibles pertes et la faible dispersion du HR-Si est démontrée. Cependant, il est aussi démontré que la géométrie du guide n'est pas optimale, conduisant à des pertes par dispersion de l'onde à l'intérieur du guide au fur et à mesure de sa propagation. Aussi, pour éviter cette dispersion, un confinement de l'onde est proposé en réduisant la largeur de la couche HR-Si pour la rendre de l'ordre de la hauteur (confinement en x et y, propagation en z) conduisant ainsi à la réalisation d'un guide d’ondes diélectrique en ruban (dielectric ribbon waveguide-DRW). Une analyse approfondie de la propagation d'une telle structure a conduit à concevoir un guide à faibles pertes d'une part, mais également à propagation monomode sur une large bande de fréquence. Une méthode de fabrication simple a été développée pour réaliser ce type de guide et un banc de mesure spécifique a été mis en place pour caractériser ce nouveau guide. Les mesures réalisées utilisent un analyseur de réseaux vectoriel (un PNA-X d'Agilent) auquel est branché deux têtes de mesure de la compagnie Virginia Diode Inc's (VDI) pour obtenir les bandes de fréquences désirées. Les sorties sont alors en guide rectangulaire standard, soit WR-8, soit WR-5 selon la plage de fréquence visée. Les résultats des mesures se comparent très bien avec les simulations réalisées avec un logiciel utilisant la méthode des éléments finis en trois dimensions (HFSS de la compagnie ANSYS) permettant d'obtenir les paramètres de la matrice de diffraction (S) mesurée par l'analyseur de réseau vectoriel. Finalement, dans le chapitre 6, un filtre passe-bande est développé comme preuve de concept pour l'utilisation du guide DRW utilisant le matériau HR-Si. Outre les faibles pertes et la propagation monomode d'un tel guide DRW, il est aussi montré dans cette thèse la facilité du processus de fabrication, le faible coût de ce procédé ainsi que la possibilité d'intégration avec d'autres composants passifs et actifs. Avec toutes ces caractéristiques très intéressantes sur différents plans, le guide DRW en HR-Si apparaît comme une solution très compétitive pour devenir un standard dans la bande de fréquence des THz.

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Garreau, Jonathan. "Étude de filtres hyperfréquence SIW et hybride-planaire SIW en technologie LTCC." Phd thesis, Université de Bretagne occidentale - Brest, 2012. http://tel.archives-ouvertes.fr/tel-00858068.

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La maîtrise de la communication et de l'information est un atout primordial dans les stratégies de pouvoir, qu'elles soient militaires, politiques ou commerciales. Celui qui est capable de transmettre l'information plus vite prend l'avantage sur les autres. Tel est le moteur de la croissance et du progrès dans le domaine des télécommunications. L'omniprésence grandissante des dispositifs communicants témoigne de l'expansion exponentielle qu'a connu ce domaine depuis les premières communications sans fil. À l'époque du all-in-one, la multiplication des applications au sein d'un même appareil nécessite l'utilisation de composants toujours plus performants et petits . Au cœur de ces systèmes, les filtres ont une importance grandissante. Dans un environnement spatial, les contraintes de fiabilité et d'encombrement sont particulièrement drastiques. Le choix des matériaux est par ailleurs limité, ce qui réduit les possibilités d'innovation. Cependant, l'amélioration de la précision et de la fiabilité dans les technologies de fabrication ouvre de nouvelles perspectives d'innovation et d'amélioration des composants. Ces travaux ont ainsi été motivés par ce souci d'apporter toujours plus de performance et de fiabilité, pour un encombrement moindre en tirant profit du potentiel offert par l'association du concept SIW et de la technologie LTCC. Les résultats mettent à jour de sérieuses dispersions technologiques. Cependant, le potentiel de l'association SIW/LTCC est démontré, et les difficultés rencontrées sont surmontables. Les filtres SIW en technologie LTCC présentent donc des atouts pour s'imposer comme une alternative sérieuse aux solutions existantes.

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Mametsa, Henri-Jose. "Contribution à l'étude de nouvelles structures de filtrage utilisant des guides d'ondes rectangulaires à section droite inhomogène." Brest, 1987. http://www.theses.fr/1987BRES2020.

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Synthèse, analyse et réalisation de nouvelles structures de filtrages utilisant des sections de guides d'ondes et des inserts diélectriques; ceux-ci étant interchangeables et facilement usinables, il suffit, avec la même structure de guides métalliques, de calculer les dimensions des inserts pour réaliser la fonction désirée, d'où une technologie à faible coût.

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Cooper, Kristie Lenahan. "Electrostatic Self-Assembly of Linear and Nonlinear Optical Thin Films." Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/27141.

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This dissertation demonstrates the feasibility of using novel electrostatic self-assembly (ESA) methods to fabricate linear and nonlinear optical thin films and components. The ESA process involves the layer-by-layer alternate adsorption of anionic and cationic complexes from aqueous solutions. Selection of the molecules in each layer, their orientation at the molecular level, and the order in which the layers are assembled determine the film's bulk optical, electronic, magnetic, thermal, mechanical and other properties. In this work, the capability of nanoscale control over film optical properties allowed the fabrication of complicated refractive index profiles required for linear optical interference filters. The inherent ordered nature of ESA films yielded extremely stable noncentrosymmetric thin films for second-order nonlinear optical applications. The ESA technique offers numerous advantages over conventional thin film fabrication methods and offers great potential in commercial applications such as reflectance and AR filters, EO waveguides and modulators and other optoelectronic devices. The structure of each monolayer in ESA films is dependent on the processing parameters, producing subsequent variations in bulk film properties both intentionally and incidentally. As this method is still in its infancy, variations in ESA processing methods, including process automation, are considered first in this document. These results allowed carefully controlled refractive index experiments and the synthesis of both step and graded index structures, several microns thick. Dielectric stack, Rugate, and antireflection optical interference filters were designed, synthesized and demonstrated. c(2) films of both commercially available polymer dyes and novel polymers designed specifically for the ESA process were demonstrated using second harmonic generation. UV/vis spectroscopy, ellipsometry and atomic force microscopy analysis are presented.
Ph. D.

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14

Chan, Richard Kayip. "Dielectric resonator bandstop filters." Thesis, University of Leeds, 2011. http://etheses.whiterose.ac.uk/2742/.

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Dielectric resonators have been widely employed in wireless and satellite communication systems due to their inherently large Q allowing them to fashion low loss and narrow bandwidth filters. Recent progress has adopted these resonators in applications requiring low volume and mass for demanding specifications. The technology at present consists of an assortment of bandpass filters using dielectric resonators but there is little published material on bandstop filters employing such resonators. Bandstop filters are desirable to suppress frequencies at the front end of wireless communication systems. To meet future demands, it is imperative to reduce the costs of these filters in both volume and weight using dielectric resonators. This thesis presents compact mono-mode and dual-mode bandstop dielectric resonator structures. The former consists of a dielectric-loaded waveguide cavity filter that offers a miniaturised version to typical cavity dielectric resonator filters requiring high unloaded Qs. The niono-mode filter described is ideal for relaxed specifications requiring a lower Q resonator to replace common coaxial resonator filters. For applications requiring high bandwidth, this resonator is improved by coupling a dielectric ring resonator to a coaxial transmission line. A novel dual-mode bandstop resonator is developed taking advantage of the geometry of a cylindrical puck within a single shielded cavity to create two degenerate modes with equal resonant frequency, effectively replacing two mono-mode cavities. Miniaturisation is achieved by sitting the dielectric puck at the base of the cavity and correct phase separation between the orthogonal modes is produced from a curved uniform transmission line. The mode behaviour is observed in the physical realisations using a 3D FEM solver. Advanced filtering functions using prescribed reflection zeros is demonstrated with the simulation of a dual-cavity, dual-mode bandstop resonator where inter- and intra- cavity couplings are controlled. The miniaturisation techniques discussed in this thesis will provide cost-reduction for microwave communication systems requiring high- Q bandstop filters.

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Luhaib, Saad Wasmi Osman. "Multi-mode dielectric resonator filters." Thesis, University of Leeds, 2018. http://etheses.whiterose.ac.uk/20843/.

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Dielectric resonator (DR) filters are widely used in microwave communications due to their small size and high Q-factor. Multi-mode filters offer a further level of miniaturisation. A new multi-mode dielectric resonator filter is presented in this thesis. The TE11d dual-mode DR offers an 11% size reduction ratio compared with a coaxial air-filled filter with the same unloaded Q-factor (Qu) and about 820 MHz spurious separation from the fundamental frequency 1.95 GHz. Two coupling techniques are applied in the TE11d filter configuration. These are: ceramic puck/probe in contact and etching holes through the ceramic puck for probe installation. A 4th order Chebyshev filter dual-mode DR filter has been simulated and fabricated using each technique. The results show a good agreement between the simulation and measurement with half spurious-free window compared with non-loaded cavity. In the etching method, the spurious-free window and the Qu improved compared with unpatterned ceramic puck. The inline structure filter provides an extra improvement in the spurious window base for the planar configuration. Another approach to the dual-mode DR filter has been studied in this work. A HE11 dual-mode with ceramic puck placed at the base of the cavity presents a good size reduction ratio and acceptable spurious window. The mathematical model shows that transmission zeros (TZs) can be generated in all orientation cases of the inter-resonator coupling hole. The control range of the TZs positions was from 40 MHz from the centre frequency. A good agreement was obtained between the simulation and the measurement results. A triple-mode DR filter with two-piece of the ceramic puck in parallel has been presented. The one cavity approach offers a high Q-factor with 400 MHz suppression. A coaxial probe was used for the input/output coupling and the etching hole through the ceramic puck for inter-resonator coupling. A 3rd order Chebyshev DR filter was simulated and fabricated with two TZs on the upper sideband. The practical results show prospects in application of the filter for miniaturised microwave communications.

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Laplanche, Etienne. "Filtres à forts facteurs de qualité accordables continument." Thesis, Limoges, 2019. http://www.theses.fr/2019LIMO0064/document.

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De nouveaux besoins dans le domaine des télécommunications par satellite ont amené les industriels du secteur à se pencher sur l’optimisation des ressources en créant des systèmes reconfigurables, capables d’adapter leur fonctionnement fréquentiel en cours de mission. Cette thèse s’intéresse plus particulièrement aux multiplexeurs et à la manière de les rendre agiles à travers les filtres qui les composent ainsi qu’une adaptation de leur architecture.Dans un premier temps, le présent manuscrit dresse l’état de l’art des dispositifs accordables réalisés par les équipes de recherche du monde entier, avant de proposer des solutions mettant en œuvre une topologie de multiplexage à coupleurs hybrides. Dans un second temps, des études sont présentées portant sur une pluralité de concepts de cavités ou d’éléments de couplage accordables. Certains de ces concepts sont ensuite sélectionnés et assemblés afin de former des fonctions de filtrage et de multiplexage accordables. La dernière partie présente ainsi deux multiplexeurs accordables, l’un permettant une reconfiguration en bande étroite, l’autre en bande large, le premier ayant donné lieu à une réalisation expérimentale
New needs in the field of satellite telecommunications have led manufacturers in the sector to focus on optimizing resources by creating reconfigurable systems able to adapt their operating frequencyplan during the mission. This thesis focuses on multiplexers and how to make them agile through their architecture and the filters that compose them.This manuscript starts by realizing the state of the art oftunable filtering devices through analysis of contributions made by research teams around the world. Based on this state of art,solutions to the problematic are proposed using a hybrid coupler multiplexing topology. Then studies are presented on various tunable cavities or coupling elements concepts. Some of these concepts have been selected and assembled to form tunable filtering and multiplexing functions. The last part thus presents two tunable multiplexers, allowing narrowband or broadband reconfiguration. An experimental realization has also been conducted on the narrowband version

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Saed, Mohammed Ali. "Dielectric characterization using a Wideband Dielectric Filled Cavity (WDFC)." Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/52317.

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This dissertation summarizes the research performed towards the development, analysis, and testing of two new sample configurations used for characterizing dielectric materials over a wide band of frequencies. In the two configurations, a cylindrical cavity completely filled with a sample of the dielectric material of interest is used. The two configurations are the following: 1. The cylindrical cavity is adapted to the end of a transmission line and the reflection coefficient is measured. The complex permittivity of the dielectric sample is then derived from the measured reflection coefficient information. 2. The cylindrical cavity is placed between two transmission lines. The complex permittivity of the dielectric material can be computed from either the measured reflection coefficient or the measured transmission coefficient. The full field analysis of these configurations is carried out and the solution is obtained using the method of moments. Computer simulation experiments are performed to test the sensitivity of these techniques and predict their performance. Actual experiments on some dielectric materials with known dielectric properties are performed for verification. The first configuration is also used to characterize two thick film dielectric materials. These configurations proved to provide solutions to the many problems with the conventional configurations found in the literature.
Ph. D.

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18

Chua, Lye Heng. "Triple-mode dielectric loaded cubical cavity filters." Thesis, University of Essex, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397641.

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Mbairi, Felix D. "Some Aspects of Advanced Technologies and Signal Integrity Issues in High Frequency PCBs, with Emphasis on Planar Transmission Lines and RF/Microwave Filters." Doctoral thesis, KTH, Mikroelektronik och tillämpad fysik, MAP, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4324.

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The main focus of this thesis is placed on high frequency PCB signal Integrity Is-sues and RF/Microwave filters using EBG structures. From the signal Integrity aspect, two topics were mainly discussed. On one hand, the effect of increasing frequency on classical design rules for crosstalk reduction in PCBs was investigated experimentally and by full-wave simulations. An emphasis was placed on the 3×W spacing rule and the use of guard traces. Single-ended and differential transmission lines were considered. S-parameter measurements and simu-lations were carried out at high-frequency (up to 20 GHz). The results emphasize the necessity to reevaluate traditional design rules for their suitability in high frequency applications. Also, the impacts of using guard traces for high frequency crosstalk re-duction were clearly pointed out. On the other hand, the effect of high loss PCB ma-terials on the signal transmission characteristics of microstrip lines at high frequency (up to 20 GHz) was treated. Comparative studies were carried out on different micro-strip configurations using standard FR4 substrate and a high frequency dielectric ma-terial from Rogers, Corporation. The experimental results highlight the dramatic im-pact of high dielectric loss materials (FR4 and solder mask) and magnetic plating metal (nickel) on the high frequency signal attenuation and loss of microstrip trans-mission lines. Besides, the epoxy-based SU8 photoresist was characterized at high frequency (up to 50 GHz) using on-wafer conductor-backed coplanar waveguide transmission lines. A relative dielectric constant of 3.2 was obtained at 30 GHz. Some issues related to the processing of this material, such as cracks, hard-skin, etc, were also discussed. Regarding RF/Microwave filters, the concept of Electromagnetic Band Gap (EBG) was used to design and fabricate novel microstrip bandstop filters using periodically modified substrate. The proposed EBG structures, which don’t suffer conductor backing issues, exhibit interesting frequency response characteristics. The limitations of modeling and simulation tools in terms of speed and accuracy are also examined in this thesis. Experiments and simulations were carried out show-ing the inadequacies of the Spice diode model for the simulations in power electronics. Also, an Artificial Neural Network (ANN) model was proposed as an alternative and a complement to full-wave solvers, for a quick and sufficiently accurate simulation of interconnects. A software implementation of this model using Matlab’s ANN toolbox was shown to considerably reduce (by over 800 times) the simulation time of microstrip lines using full-wave solvers such as Ansoft’s HFSS and CST’s MWS. Finally, a novel cooling structure using a double heatsink for high performance electronics was presented. Methods for optimizing this structure were also discussed.
QC 20100809

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20

Walker, Vanessa Evelyne Guillemette. "Dielectric resonators and filters for cellular base-stations." Thesis, University of Leeds, 2003. http://etheses.whiterose.ac.uk/2726/.

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The investigation into three types of dielectric resonators for use in base-station filtering applications is presented. The triple-mode cubic TE016 resonator is shown to have good performance for high Q applications. Its suitability for realising conventional narrowband selective bandpass filter responses is proved. The effect on the response of spurious intercavity couplings through irises is studied. The triple-mode cubic TE016 resonator is also used for the realisation of a novel type of filter, the even-odd hybrid mode reflection filter, which eliminates the need for cross-couplings for any symmetrical frequency response. The insensitivity of the new type of filter to most spurious couplings is shown in the case of a sixth degree elliptic filter. The drawbacks of this type of filter are also described. The new dual-mode conductor-loaded dielectric resonator is presented. An exact model of the resonator is necessary for an accurate study of this resonator. The axial mode-matching technique is used. The relative numbers of modes to use in each section of the model for optimum convergence primarily depend on the mode type and the relative diameters of the dielectric cylinder and the metal disc. The convergence of the resonant frequencies is good. That of the quality factors is slower but still provide useful approximate results. These convergences are affected respectively by large electric and magnetic field amplitudes in singularity regions. The resonant frequency and Q. of the fundamental mode are primarily dependent on the diameter and height of the dielectric cylinder respectively. The resonator geometry is optimised for Qu and spurious separation at 900 MHz and trade-offs between the two criteria are quantified. The resonator is found to be particularly suited for medium Q applications, i. e. between 4000 and 7000. The third resonator, the dielectric-loaded TEO,, resonator, is shown to be well suited for applications around 2 GHz and requiring Qu's of a few thousands. Theoptimum cavity cross-section dimensions for maximum Qu volume are almost constant over a wide range of cavity diameters. The trade-off between Qu and spurious separation is explained. Coupling bandwidth limitations in the case of off-line cavities are found to be solvable by using off-centred resonators. 80 MHz wide filters, optimised for ease of manufacturing, are built.

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21

Donado, Morcillo Carlos Alberto. "Development of lightweight and low-cost microwave components for remote-sensing applications." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47532.

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The objective of the proposed research is to design, implement, and characterize low-cost, lightweight front-end components and subsystems in the microwave domain through innovative packaging architectures for remote sensing applications. Particular emphasis is placed on system-on-package (SoP) solutions implemented in organic substrates as a low-cost alternative to conventional, expensive, rigid, and fragile radio- frequency substrates. To this end, the dielectric properties of organic substrates RT/duroid 5880, 6002 and 6202 are presented from 30 GHz to 70 GHz, covering most of the Ka and V radar bands, giving also a thorough insight on the uncertainty of the microstrip ring resonator method by means of the Monte Carlo uncertainty analysis. Additionally, an ultra-thin, high-power antenna-array technology, with transmit/ receive (T/R) functionality is introduced for mobile applications in the X band. Two lightweight SoP T/R array panels are presented in this work using novel technologies such as Silicon Germanium integrated circuits and microelectromechanical system switches on a hybrid organic package of liquid crystal polymer and RT/duroid 5880LZ. A maximum power of 47 dBm is achieved in a package with a thickness of 1.8 mm without the need of bulky thermal management devices. Finally, to address the thermal limitations of thin-film substrates of interest (liquid crystal polymer, RT/duroid 6002, alumina and Aluminum Nitride), a thermal assessment of microstrip structures is presented in the X band, along with the thermal characterization of the dielectric properties of RT/duroid 6002 from 20 C to 200 C and from 30 GHz to 70 GHz. Additional high-power, X-band technologies presented in this work include: a novel and compact topology for evanescent mode filters, and low-profile Wilkinson power dividers implemented on Aluminum Nitride using Tantalum Nitride thin-film resistors.

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Nakhwal, Jaspal Singh. "Investigation of microwave converters using Perovskite-type materials." Thesis, Leeds Beckett University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314814.

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23

Golt, Michael C. "Magnetic and dielectric properties of magneto-dielectric materials consisting of oriented, iron flake filler within a thermoplastic host." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 150 p, 2008. http://proquest.umi.com/pqdweb?did=1597633721&sid=13&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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24

Noori, Ahmed Sabah. "Tunable microwave filters based on dielectric split ring resonators." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8651/.

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This thesis investigates a new type of microwave tunable filter; the filter is designed based on a new type of resonator called Dielectric Split Ring Resonator (Dielectric-SRR). The new tunable filter is utilised to tune the filter bandwidth at about 2.3 GHz. This bandwidth tuning is achieved by rotating the filter resonators and without adding tuning elements such as screws or varactor diodes. In the measurement the filter resonators are rotated by hand. This thesis also investigates the new Dielectric-SRRs in term of their losses and unloaded quality factor. These new microwave resonators are designed with a configuration similar to the conventional metal Split Ring Resonators (Metal-SRR), but made from dielectric material of high dielectric constant. The new Dielectric-SRR achieved unloaded quality factor \(Q\)\(_u\) 3 times higher than the \(Q\)\(_u\) value of the conventional Metal-SRR. Besides the new tunable filter, a new class of non-tunable filter with two different configurations is investigated. The two filters are designed based on the new Dielectric-SRRs, the first design is 3rd order Chebyshev filter, and the second is a 4th order filter with two symmetric transmission zeros. The non-tunable filters achieved excellent measured performance, and good agreement between measurements and simulations.

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DeSandre, Lewis Francis. "LASER DAMAGE MEASUREMENTS ON ALL-DIELECTRIC NARROW-BAND FILTERS." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275258.

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26

Edquist, Anders. "Electrothermal Design and Analysis of Dielectric TE01-mode Resonator Filters." Thesis, KTH, Elektroteknisk teori och konstruktion, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-166830.

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The use of dielectric resonator filters is very common in the telecommunications industry for applications with demanding filtering requirements. For high power applications in particular, TE01-mode dielectric resonators are often used because of its low losses and excellent peak power handling capabilities. The essence of this work is to great extent focused around the fact that even a small amount of dissipated power can give rise to a large temperature increase if the heat transfer is insufficient. A temperature increase due to self-heating translates into a degradation of filter performance. Understanding the mechanisms behind this degradation is vital in order to compensate for these effects. Computer simulations can successfully be used to characterise the electrical and thermal behaviour of these devices. However, if the filter in question is not properly tuned when running the analysis the results will bring little or no value. This work outlines an efficient filter design flow based on Port Tuning in order to overcome this tuning issue. By carefully studying both a single resonator and a realistic filter example using CFD analysis the heat transfer mechanisms can be quantified and the dominant terms can be identified. Based on these results, a simplified model for the thermal analysis can then be established. A coupled analysis including electromagnetic, thermal and structural analysis is then demonstrated that predicts the performance degradation of the filter response. It is also demonstrated how these effects can be compensated for.
Inom telekomindustrin är dielektriska resonatorer vanligt förekommande i filtertillämpningar med krävande prestanda. För högeffekttillampningar i synnerhet används ofta TE01-mod resonatorer på grund av sina låga förluster och utmärkta effekttålighet. Kärnan i detta arbete kretsar kring det faktum att även små effektförluster kan leda till stora temperaturförandringar om värmetransporten är otillräcklig. En sådan temperaturökning på grund av egenuppvarmning yttrar sig i termer av en församring av filterprestandan. En förståelse för mekanismerna bakom denna prestandaförsamring är nödvandig for att lyckas kompensera bort dessa effekter. Datorsimuleringar kan framgångsrikt användas för att karraktärisera dessa komponenter såväl elektriskt som termiskt. Om filtret i fråga däremot inte är trimmat i simuleringen blir värdet av analysen begränsat eller rent av obefintligt. I detta arbete presenteras en effektiv designmetodik baserat på Port Tuning som överbryggar denna trimproblematik. Genom att sedan noggrant studera en ensam resonator och ett mer realistiskt filterexempel med hjälp av CFDanalys kan mekanismerna bakom värmeledningen kvantifieras och de dominerande termerna identifieras. Baserat på dessa resultat kan sedan en förenklad modell för den termiska analysen byggas. Det kan sedan visas hur en kopplad elektromagnetisk-, termisk- och strukturmekanisk analys kan användas fär att prediktera försämringarna av filter-responsen. Det visas också hur dessa effekter sedan kan kompenseras bort.

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Chuma, Joseph Monamati. "Compact single and dual mode dielectric resonator filters for mobile communications." Thesis, University of Essex, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343502.

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28

Miller, Gregory A. "A circuit model for two-path cutoff waveguide dielectric resonator filters." Thesis, Monterey, Calif. : Naval Postgraduate School, 1992. http://handle.dtic.mil/100.2/ADA247785.

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Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, March 1992.
Thesis Advisor: Knorr, Jeffrey B. "March 1992." Includes bibliographical references (p. 58-59). Also available in print.

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29

Virdee, Balbir Singh. "The design and realisation of electronically tunable dielectric resonator microstrip filters." Thesis, London Metropolitan University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307112.

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Many of todays' sophisticated communication systems, particularly those operating in the microwave frequency range, have a growing demand for highly selective and frequency agile filters with fast tuning rates. At microwave frequencies above 2GHz, filters that combine both tuning speed and high selectivity are difficult to realise. Unloaded Q values in the range of 1000 are required for reasonable selectivity. At present, these requirements with the exception of tuning speed are mainly fulfilled by electronically tuned filters employing yttrium iron garnet (YIG) resonators. An alternative solution to this problem is to utilise high-Q dielectric resonators (DRs) in-conjunction with an appropriate tuning mechanism to realise tunable filters. DRs can provide unloaded Q-factors comparable to waveguide resonators (typically 10,000 @ 10GHz), but at a substantially lower weight and smaller volume. DRs are also compatible with a microstrip environment which eliminates the need for microstrip to waveguide adaptors. This thesis is devoted to the study of the design and realisation of electronically tuned microwave filters employing dielectric resonators. Knowledge of the values of the coupling coefficient between a pair of DRs is essential for the design of both the bandpass and bandstop filters using these resonators. This necessitates the use of an accurate expression for the coupling coefficient which was derived by performing an electromagnetic analysis on the DR structure. This analysis also took into account the effects of the actual circuit environment such as the resonator support spacer and the dimensions of the enclosure. The experimental data presented shows very good agreement with the computed data. Novel techniques for the tuning of the DR operating in its fundamental mode are presented. These tuning configurations incorporating GaAs varactor diodes have been investigated to determine a circuit which greatly perturbs the DR fundamental mode. The amount of tuning that can be obtained by these methods exceeds more than 60MHz of the unperturbed value of resonant frequency with acceptable amount of Q-factor degradation. These tuning characteristics are superior to similar devices reported to date. A simple analytical expression is also derived for determining the tuning range of such a structure. Techniques for the design of novel electronically tunable DR bandpass and bandstop filters having either a Chebyshev or Butterworth response are presented. Design for prescribed response, starting from a low-pass lumped-element prototype filter is outlined. The bandpass filter structure consists of cascaded resonators, with the end resonators coupled to microstrip arcs on a substrate, whereas, the bandstop filter consists of a microstrip line with resonators mounted at intervals of one-quarter-wavelength. Tuning is achieved by varying a bias voltage to the varactor. The measured performances of several practical devices operating in the S-band are presented, these agree closely with theory. The centre frequency of these filters is within 2.46% and the bandwidth is within 3.75% of the desired values.

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30

Ramadugu, Jaya Chandra. "Design of Microwave Band Stop and Band Pass Filters Based on BST Thin Film Varactor Technology." University of Dayton / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1386695003.

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31

Donado, Morcillo Carlos Alberto. "Development of lightweight and low-cost microwave components for remote-sensing applications." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/51733.

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The objective of the proposed research is to design, implement, and characterize low-cost, lightweight front-end components and subsystems in the microwave domain through innovative packaging architectures for remote sensing applications. Particular emphasis is placed on system-on-package (SoP) solutions implemented in organic substrates as a low-cost alternative to conventional, expensive, rigid, and fragile radio- frequency substrates. To this end, the dielectric properties of organic substrates RT/duroid 5880, 6002 and 6202 are presented from 30 GHz to 70 GHz, covering most of the Ka and V radar bands, giving also a thorough insight on the uncertainty of the microstrip ring resonator method by means of the Monte Carlo uncertainty analysis. Additionally, an ultra-thin, high-power antenna-array technology, with transmit/ receive (T/R) functionality is introduced for mobile applications in the X band. Two lightweight SoP T/R array panels are presented in this work using novel technologies such as Silicon Germanium integrated circuits and microelectromechanical system switches on a hybrid organic package of liquid crystal polymer and RT/duroid 5880LZ. A maximum power of 47 dBm is achieved in a package with a thickness of 1.8 mm without the need of bulky thermal management devices. Finally, to address the thermal limitations of thin-film substrates of interest (liquid crystal polymer, RT/duroid 6002, alumina and Aluminum Nitride), a thermal assessment of microstrip structures is presented in the X band, along with the thermal characterization of the dielectric properties of RT/duroid 6002 from 20 ºC to 200 ºC and from 30 GHz to 70 GHz. Additional high-power, X-band technologies presented in this work include: a novel and compact topology for evanescent mode filters, and low-profile Wilkinson power dividers implemented on Aluminum Nitride using Tantalum Nitride thin-film resistors.

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32

Pelteku, Altin E. "Adaptive Suppression of Interfering Signals in Communication Systems." Digital WPI, 2013. https://digitalcommons.wpi.edu/etd-dissertations/138.

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The growth in the number of wireless devices and applications underscores the need for characterizing and mitigating interference induced problems such as distortion and blocking. A typical interference scenario involves the detection of a small amplitude signal of interest (SOI) in the presence of a large amplitude interfering signal; it is desirable to attenuate the interfering signal while preserving the integrity of SOI and an appropriate dynamic range. If the frequency of the interfering signal varies or is unknown, an adaptive notch function must be applied in order to maintain adequate attenuation. This work explores the performance space of a phase cancellation technique used in implementing the desired notch function for communication systems in the 1-3 GHz frequency range. A system level model constructed with MATLAB and related simulation results assist in building the theoretical foundation for setting performance bounds on the implemented solution and deriving hardware specifications for the RF notch subsystem devices. Simulations and measurements are presented for a Low Noise Amplifer (LNA), voltage variable attenuators, bandpass filters and phase shifters. Ultimately, full system tests provide a measure of merit for this work as well as invaluable lessons learned. The emphasis of this project is the on-wafer LNA measurements, dependence of IC system performance on mismatches and overall system performance tests. Where possible, predictions are plotted alongside measured data. The reasonable match between the two validates system and component models and more than compensates for the painstaking modeling efforts. Most importantly, using the signal to interferer ratio (SIR) as a figure of merit, experimental results demonstrate up to 58 dB of SIR improvement. This number represents a remarkable advancement in interference rejection at RF or microwave frequencies.

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Mohammad-Taheri, Mahmoud. "Analysis of cylindrical cavity resonators loaded axisymmetrically with dielectrics for multi-mode microwave filter design." Thesis, University of Essex, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236562.

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AL-Ghezi, Hammid. "Optical Propagation in Anisotropic Metamaterials: Application to Analysis and Design of Metallo-Dielectric Filters." University of Dayton / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1628263495632462.

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Jäverberg, Nadejda. "Dielectric properties of poly(ethyelene-co-butyl acrylate) filled with Alumina nanoparticles." Licentiate thesis, KTH, Elektroteknisk teori och konstruktion, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-31407.

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In this work dielectric properties of the poly(ethylene-co-butyl acrylate)filled with alumina nanoparticles are evaluated. These nanocomposite materialswere manufactured at the department of Fibre and Polymer Technology,KTH.This study is limited to the properties of general importance for the AC applications.The dielectric permittivity of the nanocomposite materials wasstudied as a function of filler size, filler content, coating, temperature and airhumidity used for conditioning of the samples. The ultimate goal with thisproject is to describe the influence of material composition, temperature andair humidity on the dielectric properties and model these dependencies.In this thesis the experimental setup for voltage endurance testing of thenanocomposites, namely studying applied voltage frequency dependence ofpartial discharges in electrical trees, with a possibility of following electricaltreeing optically, was developed and described.The dielectric spectroscopy measurements were performed on thoroughly driednanocomposites - so-called dry DS study. It was shown that the experimentaldata can be fitted with Havriliak-Negami approximation, which justifiesthe correctness of the measurement results. It has been shown that addingnanoparticles to the EBA matrix changes the low frequency dispersion significantlyfor the dried samples. It was also indicated that the particle coatingused has very low impact on the resulting permittivity of the thoroughly driedsamples. From the dry DS studies it was suggested that the main cause ofthe scattering in data between the dry samples is most likely the influenceof the material inhomogeneity and possibly the moisture absorption. Thisleads to a possibility of using dielectric spectroscopy as a tool for probing thedispersion of nanoparticles in the polymer matrix.The dielectric spectroscopy measurements were also carried out on the nanocompositesconditioned in the environments with different humidity levels of air inorder to study the influence of absorbed water on the dielectric permittivity- so-called wet DS study. From the wet study it was shown that for the wetsamples the amplitude of the loss peak is defined by the filler size, filler contentand coating used; while its position in frequency domain is determinedby the coating and the humidity level used for conditioning.
QC 20110315

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Troutman, Tia Shawana. "Development of low viscosity, high dielectric constant polymers for integral passive applications." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/8683.

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Sousa, Washington da Silva. "Estudo da relaxação dielétrica de filmes ultrafinos de poliestireno sulfonado." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-15072009-142644/.

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Ionômeros são polímeros carregados que possuem uma variedade de propriedades elétricas e que recentemente vêm sendo aplicados como camadas de transporte em dispositivos poliméricos. Em particular, camadas ultrafinas de ionômeros são depositadas entre o eletrodo e o polímero eletrônico em OLEDs para aumentar a eficiência da injeção de cargas. Entretanto o sucesso desta aplicação envolve fenômenos de armazenamento e mecanismos de transportes de cargas dentro do ionômero que ainda não são claramente entendidos. Neste trabalho foi utilizada a técnica da corrente despolarização termoestimulada (TSDC) com o propósito de esclarecer alguns efeitos relacionados a esse fenômeno. Nós utilizamos o poliestireno sulfonado (X-SPS) com lítio (X = Li) ou potássio (X = K) como contraíon. Foram obtidos filmes ultrafinos com 50 nm de espessura por spincoating obtendo a estrutura metal-polímero-metal para estudo, tendo como metal o alumínio. A técnica de TSDC consiste no aquecimento de uma amostra previamente polarizada a um taxa de aquecimento constante e a corrente de despolarização é medida em função da temperatura da amostra. Os resultados experimentais mostraram que cada termograma apresenta dois picos, sendo que um dos deles mostrou-se fortemente dependente das condições de polarização, ou seja, dependendo da temperatura de polarização e da intensidade do campo de polarização. Os picos foram estudados através da cinética de primeira ordem para a dinâmica de armazenamento e transporte, e dos ajustes teórico-experimental foram obtidos importantes parâmetros, tal como, a energia de ativação e concentração de espécies ativas.
Ionomers are charged polymers that exhibit a great variety of electrical properties and more recently they have been applied as transport layers at polymer devices. In particular, thin films of ionomer have been deposited between the electrodes and the electronic polymers in OLEDs to improve the efficiency of the charge injection. Despite the success of such application, the involved phenomena related to the charge storage and transport mechanisms inside the ionomer thin layer are not clear yet. In this work we used thermal stimulated depolarization current technique (TSDC) with the purpose to elucidate such phenomena. We used for this a sulfonated polystyrene (X-SPS) having lithium (X = Li) or potassium (X = K) as cation counter-ions, and we make structure of metal-polymer-metal in which the polymer is a thin film of SPS, at about 50 nm thick and deposited by spincoating, having aluminum as metal. TSDC technique consists of warm up a previously polarized sample at a constant rate of heating and measure the depolarization current in function of the temperature. The experimental results showed that each thermogram presents two peaks, one of them very dependent on the polarization conditions, i. e., it depends on the polarization temperature and the intensity of the polarization bias. The peaks were studied by considering first order trapping-detrapping (or dipole relaxation) kinetics, from which important parameters, as the activation energy, were obtained.

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Jäverberg, Nadejda. "Electrical Insulating Properties of Poly(Ethylene-co-Butyl Acrylate) Filled with Alumina Nanoparticles." Doctoral thesis, KTH, Elektroteknisk teori och konstruktion, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-116862.

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In this work the electrical insulating properties of the nanocomposite materials based on poly(ethylene-co-butyl acrylate) filled with alumina nanoparticles are studied. The dielectric properties chosen for the evaluation are the dielectric permittivity and loss as well as the breakdown strength and the pre-breakdown currents. The reason for choosing these particular properties is partly due to the importance of these for the general electrical applications and partly due to the uncertainties involved for these particular properties of the nanocomposite materials. The importance of moisture absorption for the dielectric properties is outlined in this work. All measurements were performed in both dry conditions and after conditioning of the materials in humid environment until saturation. The data for moisture absorption was taken from the water absorption study performed at the Department of Fibre and Polymer Technology, KTH. The dielectric spectroscopy in frequency domain was employed for measuring dielectric permittivity and loss. Havriliak-Negami approximation was used for characterization of the measurement data and at the same time ensuring the fulfillment of the Kramers-Kronig relations. Results from the dielectric spectroscopy study in dry conditions suggest that dielectric spectroscopy can be used for evaluating nanoparticle dispersion in the host matrix, based on correlation between the morphology data obtained from SEM investigation and the scatter in the dielectric loss. The dielectric spectroscopy study performed on the nanocomposites after conditioning in humid environment showed that absorbed moisture has a distinct impact on the dielectric loss. Especially pronounced is its’ influence on the frequency behavior, when the dielectric loss peaks are shifted towards higher frequencies with increased moisture content. The nanocomposite materials characterized by higher specific surface area generally exhibit higher dielectric losses. Surface functionalization of the nanoparticles does not seem to have much influence on the dielectric loss in dry conditions. After conditioning in humid environment, however, the surface modification was shown to have a significant impact. Temperature is another significant factor for the frequency behavior of the dielectric loss: it was found that the studied nanocomposites can be characterized by Arrhenius activation. The breakdown strength and pre-breakdown currents study outlined the influence of moisture as well. The study indicated that surface treatment of the nanoparticles can enhance properties of the nanocomposite materials, namely aminopropyltriethoxy silane was an especially successful choice: • The highest breakdown strength was determined by the study for NDA6 material formulation in dry conditions. • After conditioning in humid environment the NDA6 material continued showing the best breakdown strength among the nanocomposite mate rials, as well as this value was close to the breakdown strength of the reference unfilled material. This study confirms the existence of the optimal nanofiller content or rather optimal specific surface area of the dispersed nanoparticles in the host matrix. The latter is supported by the comparison between the nanocomposites based on nanoparticles with two different specific surface areas, which shows that the dielectric properties worsen, i.e. the dielectric losses increase and the influence of absorbed moisture on the breakdown strength becomes more pronounced, for nanomaterials with larger specific surface area. The pre-breakdown currents were found to follow space-charge limited conduction mechanism reasonably well. The following conduction regimes were identified: constant region (likely due to measurement difficulties at low field strengths), Ohm’s regime, trap-filled-limit regime and trapfree dielectric regime. The breakdown usually occurred either during the trap-filled-limit regime, when the current increased dramatically for the small change in electric field, or during the trapfree dielectric regime. The threshold values between different conduction regimes seem to correlate well with the oxidation induction times (OIT), which in turn depend on the total specific surface area. The pre-breakdown currents tend to be highest for the materials filled with the untreated nanoparticles. Increased absorbed moisture content causes higher pre-breakdown currents for the nanocomposite materials, while for the reference unfilled material the pre-breakdown currents do not show such tendency. Generally it can be said that the repeatability in the measured data is higher for the nanocomposite materials in comparison to the unfilled host material, as was demonstrated by both dielectric spectroscopy and breakdown studies.

QC 20130207

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Williamson, Jaimal Mallory. "Incorporation of air-filled pores/forms in a polyimide/benzocyclobutene matrix using a sacrifical commerical polymer for low K microelectronic applications." Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/19101.

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Cremasco, Paula Figueiredo Matheus. "Instrumentação para a caracterização dielétrica de filmes biodegradáveis." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/74/74133/tde-03052016-144535/.

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A caracterização dielétrica de um material pode ser usada como uma técnica não destrutiva para avaliar e monitorar sua qualidade, bem como no entendimento da relação estrutura-propriedade de um material, através de suas propriedades dielétricas em função da frequência, temperatura, composição química do material, dentre outros. Na literatura há escassez de trabalhos e dados de caracterização dielétrica de filmes a base de biopolímeros. Diante desse contexto, o objetivo deste trabalho foi o desenvolvimento e a construção de uma instrumentação alternativa a equipamentos disponíveis no mercado, como analisadores de rede e de impedância, que pudesse ser utilizada para a caracterização dielétrica de filmes biodegradáveis a base de gelatina. Foi utilizado o método de placas paralelas na determinação da parte real da permissividade conhecida como permissividade relativa ou constante dielétrica (ε\'). O circuito utilizado para a instrumentação foi um oscilador astável com funcionamento baseado no amplificador operacional (741) chaveado pela carga de um capacitor de placas paralelas cujo dielétrico foi uma amostra de filme biodegradável. A partir dos valores da frequência de oscilação e geometria do capacitor, foi possível calcular a capacitância de cada amostra e, consequentemente obter os valores da permissividade relativa do filme, usando relações básicas bem estabelecidas. Os filmes de gelatina foram produzidos pela técnica de casting sendo utilizados como plastificantes o glicerol (G), o sorbitol (S) e suas misturas, na proporção (G:S) de 30:70, 50:50 e 70:30. Os filmes foram caracterizados quanto à umidade e cristalinidade. A permissividade relativa (ε\') dos filmes, determinada a temperatura ambiente, foi avaliada em função da frequência (5 a 50 kHz), tempo de armazenamento, do teor de umidade e tipo de plastificante. A instrumentação projetada e construída foi capaz de medir com precisão a permissividade relativa das amostras, sendo que essa propriedade diminuiu com o aumento da frequência para todos os filmes. Mantendo-se a frequência constante, não houve variação de ε\' para os filmes de gelatina, independente do plastificante, ao longo de um mês de armazenamento a 24 ± 3 °C. O efeito da umidade foi observado em frequências menores que 25 kHz, sendo que quanto maior o teor de umidade maior a permissividade relativa. O efeito do tipo de plastificante na permissividade relativa dos filmes foi observado a baixas frequências (5 kHz) e filmes plastificados com sorbitol apresentaram maiores valores de ε\'. Os filmes plastificados com maior teor de umidade apresentaram menor cristalinidade, portanto maior mobilidade molecular e consequentemente maior a permissividade relativa.
The dielectric characteristics of a material can be used as a non-destructive technique to evaluate and monitor the quality as well as the understanding of the structure-property of a material, through its dielectric properties as a function of frequency, temperature, chemical composition of the material, among others. In the literature there are few studies and data of dielectric characterization of films based on biopolymers. In this context, the objective of this research was the development and construction of an alternative instrumentation equipment on the market, such as network and impedance analyzers, which could be used for the dielectric characterization of biodegradable films based on gelatin. The method of parallel plates was used to determine the real part of permittivity known as relative permittivity or dielectric constant (ε\'). The circuit used for the instrumentation was an astable oscillator operation based on operational amplifier (741) switched by the load of a parallel plate capacitor whose dielectric was a sample of the biodegradable film. From the values of the oscillation frequency and geometry of the capacitor, it was possible to calculate the capacitance of each sample and thus obtaining values of the relative permittivity of the film, using well established basic relationships. Gelatin films were produced by casting technique being used as plasticizer glycerol (G), sorbitol (S) and mixtures thereof, in proportion (G:S) 30:70, 50:50 and 70:30. The films were characterized for moisture and crystallinity. The relative permittivity (ε\') of the films, determined at room temperature, was evaluated as a function of frequency (5-50 kHz), storage time, moisture content and type of plasticizer. The designed and constructed instrumentation was able to accurately measure the relative permittivity of the samples, being that this property decreased with increasing frequency for all films. Keeping constant frequency, there was no variation in ε\' for the gelatin films, independent of the plasticizer over one month of storage at 24 ± 3 °C. The moisture effect was observed at frequencies lower than 25 kHz, how bigger the moisture content the higher the relative permittivity. The effect of the plasticizer type in relative permittivity of the films were observed at low frequency (5 kHz) and plasticized films with sorbitol have higher ε\' values. The plasticized films with higher moisture content exhibit lower crystallinity, hence larger molecular mobility and consequently higher the relative permittivity.

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Sorooshian, Jamshid. "Tribological, Thermal and Kinetic Characterization of Dielectric and Metal Chemical Mechanical Planarization Processes." Diss., Tucson, Arizona : University of Arizona, 2005. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu%5Fetd%5F1126%5F1%5Fm.pdf&type=application/pdf.

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Mendonça, Bianca Jardim. "Produção e caracterização de filmes finos de TiO2." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-03052018-111901/.

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Nesse trabalho foram fabricados filmes finos de TiO2 por RF magnetron sputtering reativo sobre substrato de silício (1 0 0). A pressão parcial do oxigênio na câmara foi variada de 5 a 100% em relação ao argônio. Após a deposição os filmes foram submetidos a tratamento térmico em atmosfera de oxigênio. A estequiometria dos filmes e o perfil de profundidade foram obtidos por RBS. A estrutura cristalina foi obtida por XRD. As propriedades ópticas foram obtidas por interferometria e reflectância e as elétricas por meio das curvas C-V. Os valores de espessura dos filmes sem tratamento térmico aumentaram aproximadamente 41% com o aumento do oxigênio na câmara de deposição. Essa variação está ligada ao aumento da eficiência do sputtering do alvo. Os índices de refração dos filmes sem tratamento térmico se mantiveram dentro de um intervalo de aproximadamente 2,3 a 2,4. A diminuição do band gap com o tratamento térmico é consequência da mudança de fase cristalográfica de anatase para rutila. A estequiometria TiOx dos filmes antes do tratamento térmico apresentaram valores de x entre 2,0 e 2,4. A espessura em TFU dos filmes aumentou com o percentual de oxigênio na câmara. As amostras que receberam tratamento térmico apresentaram difusão de titânio na interface do substrato e incorporação de oxigênio no filme. Os valores da constante dielétrica aumentaram com o percentual de oxigênio na câmara, em contraposição com o efeito do tratamento térmico que diminuiu o valor. Todos os resultados observados são coerentes do ponto de vista da mudança de fase anatase rutila e aumento do percentual de oxigênio na câmara.
In this work thin films of TiO2 were produced by reactive RF magnetron sputtering on silicon substrate (1 0 0). The oxygen partial pressure in the chamber was varied from 5 to 100% in relation to argon. After deposition the films were submitted to thermal treatment under an oxygen atmosphere. The stoichiometry of the films and the depth profile were obtained by RBS. The crystal structure was obtained by XRD. Its optical properties were obtained by interferometry and reflectance and the electrical were obtained by means of the C-V curves. The thickness values of films without heat treatment increased approximately 41% with the increase of oxygen in the deposition chamber. This variation is linked to the increased sputtering efficiency of the target. The refractive indexes of films without heat treatment remained within a range of about 2.3 to 2.4. The decrease of the band gap with the heat treatment is a consequence of the change of crystallographic phase from anatase to rutile. The TiOx stoichiometry of the films before the heat treatment showed values of x between 2.0 and 2.4. The TFU thickness of the films increased with the percentage of oxygen in the chamber. The samples that received heat treatment shows diffusion of titanium at the interface of the substrate and incorporation of oxygen in the film. The values of the dielectric constant increased with the percentage of oxygen in the chamber, as opposed to the effect of the thermal treatment that decreased the value. All the results observed are consistent from the point of view of the anatase - rutile phase transition and the increase in the oxygen percentage in the chamber.

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43

Powell, Mark E. "Natural convection from an array of rectangular protrusions in an enclosure filled with dielectric fluid: effects of boundary conditions." Thesis, Monterey, California. Naval Postgraduate School, 1989. http://hdl.handle.net/10945/27149.

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Doležel, Tomáš. "Vliv anorganických plniv na elektrické vlastnosti epoxidových pryskyřic." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-254475.

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This thesis deals with problems of electrical insulation materials based on epoxy composites used in the electronics industry. This thesis is divided into theoretical part focused on composite materials, their technological processing and diagnostics. It also describes dielectric materials, their properties and events taking place in their structure. The experimental section describes the measurement of electrical properties of samples of electrical insulating materials with different types of fillers.

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Borges, Fabiano Rodrigo. "Tecnicas de miniaturização de filtros dieletricos em microondas." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259794.

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Orientador: Hugo Enrique Hernandez Figueroa
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
Made available in DSpace on 2018-08-14T11:21:19Z (GMT). No. of bitstreams: 1 Borges_FabianoRodrigo.pdf: 3954935 bytes, checksum: fd0b1eeed8a2cd4e9566f172cdf86b81 (MD5) Previous issue date: 2009
Resumo: O trabalho mostra o desenvolvimento de um filtro na faixa de frequência de micro-ondas e sua construção usando ressoadores dielétricos de alta permissividade elétrica. A partir da definição matemática de uma função de transferência do tipo entrada-saída, que caracteriza um filtro, e do uso da teoria de síntese de redes, vista de um modo bastante simplificado, mostra-se como construir um circuito elétrico que realiza fisicamente a função de transferência do filtro. Em frequência de micro-ondas, contudo, elementos de parâmetros concentrados - resistores, indutores e capacitores - não se comportam como esperado, e a resposta de um circuito elétrico nesta frequência não é como a projetada. Para realizar fisicamente este circuito elétrico é necessário desenvolver conceitos eletromagnéticos, que passam pela definição de uma ferramenta importantíssima, chamada inversor de impedância, e seu equivalente acoplamento eletromagnético. Para restringir o trabalho, tratamos de filtros passa-faixa de banda estreita, o tipo mais comumente utilizado em aplicações de micro-ondas. A conversão do circuito elétrico obtido para um circuito constituído por elementos de parâmetros distribuídos é mostrada e fecha o ciclo teórico do trabalho. No campo de práticas experimentais de laboratório, medem-se parâmetros que permitem caracterizar o filtro eletromagnético obtido usando-se uma análise estatística rigorosa. Os resultados obtidos mostram que é possível partir de uma função matemática abstrata e chegar a um dispositivo de micro-ondas físico que provê a resposta projetada. Além disso, o uso de cerâmicas com permissividade elétrica elevada levou ao desenvolvimento de novas técnicas de alimentação para filtros do tipo projetado, e o requisito de ter-se uma grande banda de rejeição levou ao desenvolvimento de uma nova geometria para as cerâmicas usadas na construção do filtro.
Abstract: This work shows the development of a filter at microwave frequencies and its construction by means of dielectric resonators of high electric permittivity. Starting by the mathematical definition of a transfer function such as the kind input-output, which characterizes the filter, and the use of network synthesis theory, shown in a very simply way, one shows how to built an electric circuit that implements the filter's transfer function. At microwave frequencies, however, concentrated parameter elements - resistors, inductors and capacitors - do not behave as expected, and the output of an electric circuit at this frequency is not like the projected one. To implement this electric circuit, one needs to develop electromagnetic concepts, such as a very important tool, called impedance inverter, and its equivalent electromagnetic coupling. To restrain the scope of this work, we choose to develop bandpass filters of narrow bandwidth, the most common type used at microwave applications. The conversion from the electric circuit obtained for a circuit made by distributed parameter elements is shown and closes the theoretical cycle of this work. Regarding laboratory experimental practices, parameters are measured towards the characterization of the designed electromagnetic filter by means of a rigorous statistics analysis. The results obtained show that it is possible to begin with an abstract mathematical function and to end up with a microwave device that exhibits the designed response. Besides, the use of ceramics with high permittivity led to the development of new techniques for feeding the filters like the ones presented here, and the requirement of having a big stopband led to the development of a new geometry for the ceramics used to build the filter.
Universidade Estadual de Campi
Telecomunicações e Telemática
Mestre em Engenharia Elétrica

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Bontempo, Leonardo. "Caracterização elétrica de filmes finos de telureto com nanopartículas de ouro depositados pela técnica sputtering." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/3/3140/tde-18102012-103632/.

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Este trabalho tem como objetivo a produção e caracterização elétrica de filmes finos de telureto com nanopartículas de ouro para aplicações em microeletrônica. Filmes finos foram produzidos por magnetron sputtering a partir de alvos de telureto cerâmico e de ouro metálico. Foi desenvolvida metodologia adequada para a nucleação das nanopartículas de ouro por meio de tratamento térmico. Foram nucleadas nanopartículas de ouro a fim de que fossem observadas as influências nas propriedades elétricas. Os filmes foram depositados sobre substrato de silício e, para as medidas elétricas, ilhas de alumínio foram depositadas sobre o filme, utilizando-se os processos convencionais de microeletrônica: limpeza química, deposição por sputtering e evaporação. Com a finalidade de verificar a nucleação das nanopartículas metálicas, foram realizadas análises por Microscopia Eletrônica de Transmissão que indicaram a presença de nanopartículas metálicas, cristalinas, aproximadamente esféricas e com tamanho médio aproximado entre 1,5 e 5 nm. Outras técnicas de caracterização usadas foram microscopia de força atômica, perfilometria e extração de curvas da capacitância e condutância em função da tensão. Foram produzidos filmes com diversas espessuras com e sem nanopartículas de ouro. Por meio das medidas de capacitância em função da tensão foi possível determinar a influência das nanopartículas metálicas na constante dielétrica (k). Os resultados obtidos mostram aumento do valor de k de aproximadamente 70%, na presença de nanopartículas de ouro. Cabe ressaltar o resultado obtido para os filmes com espessura de 32,8 nm, para os quais o valor da constante dielétrica varia de 9,4 para 12,2, para tratamentos de 10 e 20 h, respectivamente. O material estudado tem possíveis aplicações em microeletrônica como dielétrico em capacitores e transistores MOS, e como camada de passivação em dispositivos de potência.
This work has the objective of production and electrical characterization f tellurite thin films containing gold nanoparticles for microelectronic applications. Thin films have been produced by magnetron sputtering from ceramic tellurite and metallic gold targets. It was developed an appropriate methodology for the gold nanoparticles nucleation by means of heat treatment. Gold nanoparticles were nucleated in order to be observed the influence on the electrical properties. The films were deposited on silicon substrate and, to the electrical measurements, aluminium islands were deposited on the film, using the conventional processes of microelectronics: chemical cleaning, deposition by sputtering and evaporation. With purpose to check the metallic nanoparticles nucleation, transmission electron microscopy measurements were performed and indicated the presence of crystalline metallic nanoparticles, with spherical shape and with average size between 1.5 and 5 nm. Other characterization techniques were used as atomic force microscopy, profilometry and electrical measurements to obtain the capacitance and conductance curves. Films have been produced with different thicknesses with and without gold nanoparticles. From capacitance measurement, it was possible to determine the metallic nanoparticles influence on the dielectric constant (k). The results obtained showed the increase of k of about 70% with the presence of gold nanoparticles. We have to remark the results obtained for thin films with 32.8 nm thickness with k varying from 9.4 to 12.2, for heat treatments during 10 and 20 h, respectively. The material studied has possible applications in microelectronics as high-k dielectrics for capacitors and transistors MOS, and as passivation layer for power devices.

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Blanco, Villalba José Francisco [Verfasser], and P. [Akademischer Betreuer] Elsner. "Volumetric characterization of the nano- and microconfiguration of nanocomposites with conductive fillers by dielectric spectroscopy / José Francisco Blanco Villalba ; Betreuer: P. Elsner." Karlsruhe : KIT-Bibliothek, 2021. http://d-nb.info/1229514716/34.

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Benedict, Terry J. "An advanced study of natural convection immersion cooling of 3 x 3 array of simulated components in an enclosure filled with dielectric liquid." Thesis, Monterey, California. Naval Postgraduate School, 1988. http://hdl.handle.net/10945/22860.

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Approved for public release; distribution is unlimited.
An experimental study has been conducted to examine the three dimensional natural convection heat transfer from an array of simulated electronic components immersed in a chamber filled with Fluorinert FC-75, a commercially available dielectric liquid. The top and bottom walls of the chamber were maintained at uniform temperature while all other surfaces were insulated. The simulated components were in the form of a 3 x 3 array of discrete protruding aluminum blocks, each with geometrical dimensions of a 20 Pin Dual-inline-Package. The components were electrically powered resulting in a range of energy dissipation levels from 0.1 to 3.1 watts. Flow visualization in steady state was accomplished using Magnesium particles illuminated by a Helium Neon laser plane. Component surface temperature measurements allowed determination of the heat transfer characteristics. Timewise fluctuations of temperature at several locations were measured with increasing power levels. Keywords: Computer programs, Electronic cooling, Protruding heat sources, Flow visualization, Convective heat transfer, Immersion cooling, Dielectric liquids, Theses. (jhd)

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Wang, Chen-Chang, and 王振昌. "Study of UHF Band Dielectric Filter." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/49034492590641066358.

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碩士
國立成功大學
電機工程研究所
84
Wireless communication technique has found applications on satellite, radar, cellular phone, and TV. The reduction of size and weight has become the main requirement for today's electronic system. Wireless communication circuit has been integrated due to the well defined VLSI technology. However, advanced research is still needed to reduce the size of microwave filter. In this work，the UHF band stripline filter was investigated. The metallic strips were sandwiched by two high dielectric constant ceramic substrate. Quasi TEM wave will propagate through the strips and perform filter. Energy is coupled from stage to stage through the gap between strips. The strips were constructed as quarter wavelength. The substrates were fabricated to be as thin as 1.38 mm in thickness for ZST material and 2.7 mm for BSST material . The properties of the filters were found to be functions of the thickness of the substrates and the width of the gaps. However，the insertion loss was less than 3 dB for all the cases with 50 ohm input impedance and good spurious mode.

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Zhang, Rui. "Novel Planar Microstrip and Dielectric Resonator Filters." Thesis, 2007. http://hdl.handle.net/10012/2753.

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Microwave filters possessing various forms are essential components in radar, satellite, and mobile communication systems. Increased demands for low-loss, miniature filters that can be mass produced at low cost have provided a significant challenge reinforcing the need for improving or even replacing the conventional microwave filters. In recent years, the concept of Photonic/Electromagnetic Bandgap (PBG/EBG) structures has attracted the attention of the microwave engineering community. The main feature of PBG/EBG structures is the existence of a bandgap in the frequency spectrum of a propagating photonic/electromagnetic wave. The motivation for adopting EBG structures stems from their capability to eliminate unwanted wave propagations in various microwave devices. This thesis investigates and proposes novel planar microstrip filters employing EBG structures in the form of slots etched on the ground plane. Such filters are not only compact, but also can improve the RF performance in both the passband and the stopband. This proposed concept is further extended to implement low-loss tunable lowpass filters, both digital and analogue, by integrating tuning elements directly into the slots. Transmission line circuit models are developed to design the proposed microstrip filters and tunable lowpass filters. To verify the concept and the validity of the developed circuit models, theoretical and experimental results are presented and carefully compared. Currently, dielectric resonator (DR) filters have been widely employed in wireless and satellite communication systems. Over the past two decades, tremendous progress has been made to reduce the size, and enhance the in-band and out-of-band performance of DR filters. However, the current approaches for implementing DR filters are relatively expensive and hardly amenable to mass production. Cost reduction remains a key limiting factor that needs to be addressed now. A new configuration of DR filters is presented in this thesis. The novel concept simplifies the assembly, integration, and alignment of DR filters, significantly reducing production time and costs. Not only is the design of the proposed multi-pole DR filters and diplexers examined, but also the fabrication technique. The experimental measurement results confirm the validity of the theoretical designs of the new filters, which makes this concept very attractive for further applications in both wireless and satellite communication.

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