Dielectric resonator antennas(DRAs) offer some attractive characteristics over conventional microstrip antennas, such as small size, low profile, light weight, ease of excitation, and high radiation efficiency at higher frequency bands. Since DRAs attract more and more attention, theoretical analysis have been insufficient to simulate various configurations of dielectric resonator antennas. Therefore some researchers introduce numerical methods to analyze DRAs, such as Finite Difference Time Domain (FDTD) method, Method of Moment (MoM), Finite Element Method (FEM). In this author, we apply two kinds of methods, including FDTD and MoM, to analysis DRA and compare the results applied these two methods. Then we simulate various configurations of dielectric resonator antennas using FDTD method. About designing the DRA construction, in this author we applied an equivalent approach to solve approximate dimensions of DRAs, and then we obtain accurate dimensions using FDTD method. In this author¡Aa DRA work at 5.8GHz have been proposed, then we using a L-shaped patch to increase impedance bandwidth. Above all, we hope to built a fast and accurate procedure to solve the resonant frequency, bandwidth, and far field pattern of DRAs. And to supply the engineer to reduce time consume in design DRAs.

No / A small dielectric resonator antenna has been designed for ultra wideband (UWB) communication system applications. The antenna element is a rectangular low permittivity ceramic block, with a dielectric constant of 9.4, and the modified T-shaped feed network includes a 50 ohm microstrip line to achieve strong coupling, and some bandwidth enhancement. The antenna performance is simulated and measured over a frequency band extending from 3100 MHz to 5500 MHz; the impedance bandwidth over this interval is 55.8% with VSWR <; 2, making the antenna suitable for UWB applications.

In this thesis a technique that is being used in another area of technology to optimize light reception in a photographic camera was also applied to the dielectric resonator antenna. The technique consisting of the use of thin film to couple the media and camera impedances resulted in a dielectric resonator antenna bandwidth enhancement technique. The bandwidth enhancement technique was found when thin film dielectric layer structure was used to couple the dielectric resonator and its feed mechanism. Remarkable good performance was detected with a coplanar waveguide fed cylindrical dielectric resonator antenna which resulted in an improvement to its fractional bandwidth from 7.41% to 50.85%. Extensive experimental work was undertaken in order to explore the extent offered in bandwidth performance by using thin film dielectric layer structure in the dielectric resonator antenna performance. The experimental tasks were designed in order to investigate the influence of the thin film dielectric layer structure in relation to its size, shape, thickness, position and direction. Experimental results were supported with simulation work with the computer simulation technology microwave studio. The pieces of the material used for undertaking this experimental work were manually handcrafted. Four different dielectric resonator antenna designs were used in order to carry out the experimental work including the coplanar waveguide fed cylindrical dielectric resonator antenna. The other three dielectric resonator antennas were implemented using the same microstrip feed mechanism. Improved performance in bandwidth was achieved for all the designs. Optimization of the incoming signal was observed when a piece of thin film dielectric layer structure was placed in position between the feed mechanism and the dielectric resonator antenna. The optimization was observed as an enhancement in both the return loss level and the bandwidth of work. Different unexpected operational modes from were activated, such modes being called perturbed modes. Two different shapes were used in this project. Cylindrical dielectric resonator antenna (ɛr = 37) from a commercial provider and two novel rectangular dielectric resonator antennas. The novel rectangular dielectric resonator antennas were created with the methodology presented in this thesis. The rectangular dielectric resonator antennas were elaborated with transparent ceramic material (ɛr = 7) and TMM10i (ɛr = 9.8) from the Rogers Corporation company. The bandwidth enhancement technique was tested in novel embedded dielectric resonator antennas. A coplanar waveguide fed embedded cylindrical dielectric resonator antenna achieved a maximum bandwidth enhancement of 156.77% around f = 3.79 GHz with a thin film dielectric layer structure modified rectangular piece on one edge. Escalation to dielectric resonator antenna design at millimeter wave frequencies was achieved by using thin film dielectric layer structure bandwidth enhancement technique and a handcrafted printed circuit board millimeter wave feed mechanism. The millimeter wave feed mechanisms were achieved using a low cost alternative technique conceived as part of this project. Millimeter wave dielectric resonator antennas were implemented using thin film dielectric layers structure. The antennas deliver an adequate performance in bandwidth. The work presented in this thesis demonstrates dielectric resonator antenna simpler geometry, simple couple schemes, small size, low profile, light weight, and ease of excitation and orientation. Other parameters have also been investigated covering reduced complexity, high degree of flexibility, ease of fabrication and the use of low cost technology to escalate to millimeter wave frequencies.

Yes / The antenna array designed to operate over 0.450-0.475 Terahertz comprises two dielectric resonators (DRs) that are stacked vertically on top of each other and placed on the surface of the slot antenna fabricated on a silicon substrate using standard CMOS technology. The slot created in the silicon substrate is meandering and is surrounded by metallic via-wall to prevent energy dissipation. The antenna has a maximum gain of 4.5dBi and radiation efficiency of 45.7% at 0.4625 THz. The combination of slot and vias transform the antenna to a metamaterial structure that provides a relatively small antenna footprint. The proposed series-fed double DRs on-chip antenna array is useful for applications in THz integrated circuits. / Partially supported by innovation programme under grant agreement H2020-MSCA-ITN-2016 SECRET-722424 and the financial support from the UK Engineering and Physical Sciences Research Council (EPSRC) under grant EP/E0/22936/1.

Este trabalho visou ao desenvolvimento de antenas de ressoador dielétrico de banda dupla em frequências de micro-ondas por meio do estabelecimento de uma metodologia de projeto para as mesmas e da proposição de configurações inéditas de antenas desse tipo. Estudos realizados sobre antenas de ressoador dielétrico e sobre suas técnicas de projeto forneceram a base para a elaboração de um procedimento de projeto para antenas de banda dupla que explora a flexibilidade das antenas de ressoador dielétrico. Empregando-se esse procedimento de projeto, duas antenas com configurações originais foram desenvolvidas para operar em frequências de micro-ondas. Uma delas é uma antena de ressoador dielétrico cilíndrica sobre plano de terra, destinada a operar nas frequências centrais de 3,94 GHz e de 5,42 GHz, com diagrama de radiação direcional e polarização circular na primeira banda de operação e com diagrama de radiação omnidirecional e polarização linear na segunda. A outra antena consiste em uma antena de ressoador dielétrico cilíndrica sobre substrato dielétrico aterrado, cujas frequências centrais de operação são 3,99 GHz e 6,20 GHz, com diagrama de radiação direcional e polarização circular em ambas as bandas de operação. O projeto das duas antenas também levou a contribuições novas adicionais em alguns temas específicos relacionados: estruturas de excitação para antenas de ressoador dielétrico, circuitos acopladores híbridos de 90° de banda dupla, circuitos de alimentação para antenas de banda dupla e modelos matemáticos para o ressoador dielétrico cilíndrico isolado no espaço livre. Os comportamentos previstos teoricamente para as antenas projetadas são confirmados por meio de resultados obtidos por simulação eletromagnética e por medição experimental, o que indica a validade das hipóteses adotadas, das configurações de antena propostas e da metodologia de projeto concebida, demonstrando também a flexibilidade desta para variadas especificações de antena. Os avanços obtidos com este trabalho e as melhorias que podem ser efetuadas sobre o mesmo são identificados examinando-se resultados recentemente publicados na literatura técnica. Este trabalho foi realizado na forma de uma pesquisa de doutorado sanduíche, desenvolvida parcialmente na University of Houston sob a supervisão do Prof. Stuart A. Long. / This work aimed at the development of microwave dual-band dielectric resonator antennas by means of establishing a design methodology for them and of proposing novel configurations of this antenna type. Studies on dielectric resonator antennas and on their design techniques provided the ground for elaborating a design procedure for dual-band antennas that exploits the flexibility of dielectric resonator antennas. By employing this design procedure, two antennas with original configurations have been developed for operation at microwave frequencies. One of them is a cylindrical dielectric resonator antenna on a ground plane, intended for operation at the center frequencies of 3.94 GHz and 5.42 GHz, with a directional radiation pattern and circular polarization in the first operating band and with an omnidirectional radiation pattern and linear polarization in the second one. The other antenna consists of a cylindrical dielectric resonator antenna on a grounded dielectric substrate, whose operating center frequencies are 3.99 GHz and 6.20 GHz, with a directional radiation pattern and circular polarization in both operating bands. The design of the two antennas also led to additional new contributions in some related specific subjects: excitation structures for dielectric resonator antennas, dual-band 90°-hybrid couplers, feeding circuits for dual-band antennas, and mathematical models for the cylindrical dielectric resonator isolated in free space. The behaviors theoretically expected for the designed antennas are confirmed by means of results obtained from electromagnetic simulation and from experimental measurements, which indicates the validity of the assumed hypotheses, of the proposed antenna configurations and of the conceived design methodology, also demonstrating the flexibility of the latter for various antenna specifications. The advances obtained with this work and the improvements that can be made on it are identified by examining results recently published in the technical literature. This work was carried out as a sandwich doctoral research, developed at the University of Houston under the supervision of Prof. Stuart A. Long.

Este trabalho visou ao desenvolvimento de antenas de ressoador dielétrico de banda dupla em frequências de micro-ondas por meio do estabelecimento de uma metodologia de projeto para as mesmas e da proposição de configurações inéditas de antenas desse tipo. Estudos realizados sobre antenas de ressoador dielétrico e sobre suas técnicas de projeto forneceram a base para a elaboração de um procedimento de projeto para antenas de banda dupla que explora a flexibilidade das antenas de ressoador dielétrico. Empregando-se esse procedimento de projeto, duas antenas com configurações originais foram desenvolvidas para operar em frequências de micro-ondas. Uma delas é uma antena de ressoador dielétrico cilíndrica sobre plano de terra, destinada a operar nas frequências centrais de 3,94 GHz e de 5,42 GHz, com diagrama de radiação direcional e polarização circular na primeira banda de operação e com diagrama de radiação omnidirecional e polarização linear na segunda. A outra antena consiste em uma antena de ressoador dielétrico cilíndrica sobre substrato dielétrico aterrado, cujas frequências centrais de operação são 3,99 GHz e 6,20 GHz, com diagrama de radiação direcional e polarização circular em ambas as bandas de operação. O projeto das duas antenas também levou a contribuições novas adicionais em alguns temas específicos relacionados: estruturas de excitação para antenas de ressoador dielétrico, circuitos acopladores híbridos de 90° de banda dupla, circuitos de alimentação para antenas de banda dupla e modelos matemáticos para o ressoador dielétrico cilíndrico isolado no espaço livre. Os comportamentos previstos teoricamente para as antenas projetadas são confirmados por meio de resultados obtidos por simulação eletromagnética e por medição experimental, o que indica a validade das hipóteses adotadas, das configurações de antena propostas e da metodologia de projeto concebida, demonstrando também a flexibilidade desta para variadas especificações de antena. Os avanços obtidos com este trabalho e as melhorias que podem ser efetuadas sobre o mesmo são identificados examinando-se resultados recentemente publicados na literatura técnica. Este trabalho foi realizado na forma de uma pesquisa de doutorado sanduíche, desenvolvida parcialmente na University of Houston sob a supervisão do Prof. Stuart A. Long. / This work aimed at the development of microwave dual-band dielectric resonator antennas by means of establishing a design methodology for them and of proposing novel configurations of this antenna type. Studies on dielectric resonator antennas and on their design techniques provided the ground for elaborating a design procedure for dual-band antennas that exploits the flexibility of dielectric resonator antennas. By employing this design procedure, two antennas with original configurations have been developed for operation at microwave frequencies. One of them is a cylindrical dielectric resonator antenna on a ground plane, intended for operation at the center frequencies of 3.94 GHz and 5.42 GHz, with a directional radiation pattern and circular polarization in the first operating band and with an omnidirectional radiation pattern and linear polarization in the second one. The other antenna consists of a cylindrical dielectric resonator antenna on a grounded dielectric substrate, whose operating center frequencies are 3.99 GHz and 6.20 GHz, with a directional radiation pattern and circular polarization in both operating bands. The design of the two antennas also led to additional new contributions in some related specific subjects: excitation structures for dielectric resonator antennas, dual-band 90°-hybrid couplers, feeding circuits for dual-band antennas, and mathematical models for the cylindrical dielectric resonator isolated in free space. The behaviors theoretically expected for the designed antennas are confirmed by means of results obtained from electromagnetic simulation and from experimental measurements, which indicates the validity of the assumed hypotheses, of the proposed antenna configurations and of the conceived design methodology, also demonstrating the flexibility of the latter for various antenna specifications. The advances obtained with this work and the improvements that can be made on it are identified by examining results recently published in the technical literature. This work was carried out as a sandwich doctoral research, developed at the University of Houston under the supervision of Prof. Stuart A. Long.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Duas contribuiÃÃes caracteristicamente distintas, nÃo obstante correlacionÃveis num mesmo sistema de telecomunicaÃÃo, sÃo apresentadas. A primeira versa sobre antenas ressoadoras constituÃdas por novas cerÃmicas dielÃtricas à base de Fe2O3. Os materiais desenvolvidos foram caracterizados na faixa de micro-ondas. Tratam-se de dielÃtricos com baixa permissividade relativa, baixa tangente de perda, e, no caso das amostras monofÃsicas, com coeficiente de temperatura na frequÃncia de ressonÃncia negativo. Posteriormente, as antenas ressoadoras dielÃtricas de geometria cilÃndrica (CDRAs) suportadas em plano de terra retangular e alimentadas por sonda monopolar sÃo analisadas segundo critÃrios de desempenho de irradiaÃÃo, quais sejam: frequÃncia de ressonÃncia, impedÃncia de entrada, largura de banda e padrÃes de irradiaÃÃo. AlÃm de experimentaÃÃo, o seu estudo envolveu procedimento computacional, no que foi promovida a comparaÃÃo de resultados. O mÃtodo dos elementos finitos, no qual està baseado o programa comercial empregado, foi utilizado para anÃlise destas antenas. Resulta que para maiores valores de permissividade relativa de uma amostra, menores sÃo a frequÃncia em que a mesma ressoa e a sua largura de banda. Ainda, foi observado satisfatÃrio casamento de impedÃncia e padrÃes de irradiaÃÃo "broadside", o que candidata os novos materiais desenvolvidos a esta importante aplicaÃÃo. Adicionalmente, mediante empilhamento dos protÃtipos monofÃsicos examinados, foi verificada a remodelagem da largura de banda em relaÃÃo Ãs contrapartidas individuais, provavelmente devido à excitaÃÃo de modos de ordem elevada das CDRAs. A segunda contribuiÃÃo està enfocada no contexto dos guias de ondas dielÃtricos operando em frequÃncias Ãpticas. Neste cenÃrio, sÃo investigados acopladores refletores de Bragg a fibra (FBGCs), estruturas resultantes da combinaÃÃo de dois dispositivos reconhecidamente versÃteis e de ampla aplicaÃÃo: redes de Bragg e acopladores direcionais. Foram apreciados dois estudos de caso numÃricos nos quais se fez promover a interaÃÃo de sinais Ãpticos com as estruturas propostas. Na medida em que descreve com satisfatÃria precisÃo as propriedades Ãpticas dos dispositivos de interesse, o modelo matemÃtico empregado à baseado na teoria dos modos acoplados. O tratamento numÃrico à realizado mediante codificaÃÃo, em linguagem de programaÃÃo FORTRAN, de um algoritmo preditivo-corretor. Considerando regimes pulsados em termos da potÃncia operacional, o problema foi analisado no domÃnio da frequÃncia e, sobretudo, no domÃnio do tempo. Em condiÃÃes especÃficas, a possibilidade de realizaÃÃo da extraÃÃo, reconfiguraÃÃo e comutaÃÃo de pulsos, exemplos de funÃÃes essenciais ao processamento totalmente Ãptico, reforÃam a importÃncia de tais estruturas hÃbridas. / Two heterogeneous contributions to modern communication systems â although fully possible to be correlated â are presented. The first one deals with resonant antennas consisting of new dielectric ceramics based on Fe2O3. These materials characterized at microwave frequency range possess low relative permittivity, low loss tangent and, concerned with the monophasic samples, negative temperature coefficient of resonant frequency. Subsequently, the cylindrical dielectric resonator antennas (CDRAs) supported on rectangular ground plane and fed by monopole are analyzed according to the following radiation performance criteria: resonant frequency, input impedance, bandwidth and radiation patterns. Besides experimentation, the study involved computational procedure, so that the results of both can be compared. A commercial software based on the finite element method was employed to examine the CDRAs. It follows that as higher is the permittivity of a material, the lower are the frequency at which it resonates as well as its bandwidth. Satisfactory impedance matching and broadside radiation patterns are observed, what enables the materials investigated to this relevant application. Additionally, the stacking of the monophasic CDRAs prototypes resulted in bandwidth enhancement, presumably due to their excited high order modes. The second contribution focuses on dielectric waveguides operating at optical frequencies, being fiber Bragg grating couplers (FBGCs) investigated in this scenario. Indeed, they result from a combination of two versatile and widely applied devices: fiber Bragg gratings and directional couplers. Two numerical case studies related to the interaction between optical signals and structures were performed. The theoretical model observed is based on the coupled mode theory since it provides a satisfactorily accurate description of the devices optical properties. By the way, the theoretical model is coded in FORTRAN programming language according to a predictor-corrector algorithm. In terms of operational power levels, analyses are carried out in frequency and (mainly) time domains. Under specific conditions, the capability of the extraction, reshaping and switching of pulses â examples of essential functions for all-optical processing â reinforces the importance of such hybrid structures.

Made available in DSpace on 2014-12-17T14:55:13Z (GMT). No. of bitstreams: 1 JoemiaLGMM_TESE.pdf: 3140610 bytes, checksum: 8bdf88d29c888d95e74fd24e403e60fc (MD5) Previous issue date: 2013-06-07 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Ceramic substrates have been investigated by researchers around the world and has achieved a high interest in the scientific community, because they had high dielectric constants and excellent performance in the structures employed. Such ceramics result in miniaturized structures with dimensions well reduced and high radiation efficiency. In this work, we have used a new ceramic material called lead zinc titanate in the form of Zn0,8Pb0,2TiO3, capable of being used as a dielectric substrate in the construction of various structures of antennas. The method used in constructing the ceramic combustion synthesis was Self- Sustained High Temperature (SHS - "Self-Propagating High-Temperature Synthesis") which is defined as a process that uses highly exothermic reactions to produce various materials. Once initiated the reaction area in the reaction mixture, the heat generated is sufficient to become self-sustaining combustion in the form of a wave that propagates converting the reaction mixture into the product of interest. Were analyzed aspects of the formation of the composite Zn0,8Pb0,2TiO3 by SHS powders and characterized. The analysis consisted of determining the parameters of the reaction for the formation of the composite, as the ignition temperature and reaction mechanisms. The production of composite Zn0,8Pb0,2TiO3 by SHS performed in the laboratory, was the result of a total control of combustion temperature and after obtaining the powder began the development of ceramics. The product was obtained in the form of regular, alternating layers of porous ceramics and was obtained by uniaxial pressing. 10 The product was characterized by analysis of dilatometry, X-ray diffraction analysis and scanning electron microscopy. One of the contributions typically defined in this work is the development of a new dielectric material, nevertheless presented previously in the literature. Therefore, the structures of the antennas presented in this work consisted of new dielectric ceramics based Zn0,8Pb0,2TiO3 usually used as dielectric substrate. The materials produced were characterized in the microwave range. These are dielectrics with high relative permittivity and low loss tangent. The Ansoft HFSS, commercial program employee, using the finite element method, and was used for analysis of antennas studied in this work / Substratos cer?micos t?m sido investigados por pesquisadores de todo o mundo e tem despertado um grande interesse na comunidade cient?fica, pelo fato de apresentarem altas constantes diel?tricas e um excelente desempenho nas estruturas empregadas. Tais cer?micas resultam em estruturas miniaturizadas, com dimens?es bem reduzidas e de alta efici?ncia de radia??o. Neste trabalho, utilizou-se um novo material cer?mico, chamado de titanato de zinco chumbo, na forma de Zn0,8Pb0,2TiO3, capaz de ser utilizado como substrato diel?trico na constru??o de diversas estruturas de antenas. O m?todo utilizado na constru??o da cer?mica foi a S?ntese por Combust?o Auto-Sustentada a Alta Temperatura (SHS Self-Propagating High-Temperature Synthesis ) que ? definido como um processo que utiliza rea??es altamente exot?rmicas para produzir os mais diversos materiais. Uma vez iniciada a rea??o numa ?rea da mistura reagente, o calor gerado ? suficiente para tornar a combust?o auto-sustent?vel, na forma de uma onda que se propaga convertendo a mistura reagente no produto de interesse. Foram analisados os aspectos da forma??o do comp?sito Zn0,8Pb0,2TiO3 por SHS e os p?s obtidos, foram caracterizados. A an?lise consistiu na determina??o dos par?metros da rea??o para a forma??o do comp?sito, como a temperatura de igni??o e os mecanismos de rea??o. A produ??o do comp?sito Zn0,8Pb0,2TiO3 por SHS, realizada em laborat?rio, foi resultado de um controle total da temperatura de combust?o e ap?s a obten??o do p? 8 iniciou-se o desenvolvimento das cer?micas. O produto foi obtido na forma de camadas regulares e altern?ncia de porosidades e as cer?micas foram obtidas por prensagem uniaxial. O produto foi caracterizado atrav?s de an?lises de dilatometria, difra??o de raios-X e an?lise de microscopia de varredura eletr?nica. Uma das contribui??es principais deste trabalho foi o desenvolvimento de um novo material diel?trico, n?o obstante apresentado anteriormente na literatura. Portanto, as estruturas das antenas apresentadas neste trabalho foram constitu?das por novas cer?micas diel?tricas ? base de Zn0,8Pb0,2TiO3, geralmente utilizado como substrato diel?trico. Os materiais desenvolvidos foram caracterizados na faixa de micro-ondas. S?o substratos diel?tricos de alta permissividade relativa e baixa tangente de perda. O software comercial empregado, Ansoft HFSS, baseado no m?todo dos elementos finitos, foi utilizado na an?lise das antenas estudadas neste trabalho

Les antennes à pointage électronique présentent des avantages significatifs dans les systèmes de communication sans fil. Malgré cela elles ne sont toujours pas implantées dans l'industrie automobile. En effet, l'espace limité et le toit en grande partie métallique freinent l’utilisation de ces aériens dans ce contexte contraint. De nombreux défis restent à relever pour concevoir un système efficace, peu encombrant, faible coût et permettant de rayonner sur 360°. L’objectif de cette thèse est donc la mise au point d’une antenne à balayage électronique pour application automobile fonctionnant dans la bande LTE. Un système de «type MIMO » est proposé. Une antenne à résonateur diélectrique efficace, multi-bandes et efficace est conçue selon une procédure de développement spécifique. Un déphaseur accordable est également mis au point et réalisé. Il utilise des commutateurs et un condensateur variable. Un déphasage de 360 degrés est obtenu, le dispositif est commandé électriquement. L’antenne et le déphaseur sont ensuite associés dans un système complet fonctionnant dans la bande LTE. Celui-ci utilise deux antennes identiques, une seule étant alimentée. Ce système complet est mesuré seul et sur le véhicule. Les résultats obtenus sont prometteurs et permettent d’envisager, moyennant quelques améliorations, une exploitation industrielle. Les études menées pour aboutir à ce dispositif sont détaillées dans le manuscrit. / Even though beam steering technology has significant advantages in wireless communication systems, it is still not implemented in the automotive industry. Indeed, the limited space and the large metal sheet on the rooftop are the challenges for such system. This thesis is focused on the design of the LTE beam steering antenna based on a MIMO system for an automotive environment. An appropriate multiband, efficient and compact Dielectric Resonator Antenna is conceived using a specific development procedure. Also, a tunable phase shifter is designed and realized with switches and a variable capacitor. It has 360 degrees phase shift and can be electrically controlled. The proposed DRA and phase shifter are integrated in a global antenna system for automotive application in the LTE band. We finally propose a MIMO system with an active beam steering radiation pattern. It is very compact and can be implemented on the vehicle rooftop. Using the proposed phase shifter, a beam steering antenna is obtained with a global coverage close to 360� for the antenna alone or on the vehicle. Measurements are made in the using context of the antenna. Finally, the developed system is, with some improvement, powerful for powerful enough for "commercial" automotive applications. The studies carried out to develop this antenna are detailed in this manuscript.

The Theory of Characteristic Modes is being adopted by many research groups around the world in the last decade. This topic and their use in different metallic antenna design is growing very fast. However, most of the applications has been only concentrated on conducting surfaces without any physical knowledge about its limitations and its physical interpretation. As far as dielectric bodies are concerned, there have not been so many published articles. The reason is that there are different integro-differential formulations and the interpretation of their solutions is not as obvious as in conducting bodies. Here, a theoretical interpretation considering loss-less conducting and dielectric bodies is presented. The conclusions drawn in this thesis will allow us to better understand the solutions of the Theory of Characteristic Modes and their limitations. This is important for antenna engineering. In addition, this analysis will allow to develop a novel method for the design of antennas based on dielectric resonators, DRA. This method is called Substructure based-PMCHWT method, and is based on the implementation of the Schur complements of the method of moments matrix operator. This study permits to optimize the radiation bandwidth in the same analysis process for both, the dielectric and the feed, e.g. slot. Moreover, it allows to understand how the slot behaves in the presence of the dielectric resonator and vice versa. This method can also be used to design DRA using low permittivities. This is important in the design of DRA because the feed perturbs the system and produces a shift in the resonances of the characteristic modes. So, therefore, by considering the feed system in the characteristic modes analysis a more realistic results than a conventional analysis is obtained. On the other hand, the resonances of the characteristic modes at low permittivities are displaced from what are the natural resonances of the dielectric resonator and also the corresponding S11 resonance. Thus, designing with this new method it can draw new conclusions about the design of DRA using the Theory of Characteristic Modes. / En la última década, la teoría de los modos característicos está siendo utilizada por muchos grupos de investigación en todo el mundo. Este tema y su uso en diferentes diseños de antenas metálicas está creciendo muy rápido. Sin embargo, la mayoría de las aplicaciones se han concentrado únicamente en antenas metálicas sin ningún conocimiento físico acerca de sus limitaciones y su interpretación física. En lo que se refiere a cuerpos dieléctricos, no han habido tantos artículos publicados como en metales. La razón es que existen diferentes formulaciones integro-diferenciales y la interpretación de sus soluciones no es tan obvia como en cuerpos metálicos. En esta tesis se presenta una interpretación física de las soluciones de la Teoría de Modos Característicos al considerar cuerpos metálicos y dieléctricos sin pérdidas. Las conclusiones de esta tesis nos permitirán comprender mejor las soluciones de la Teoría de Modos Característicos y sus limitaciones. Esto es importante en ingeniería de antenas. Además, este análisis permitirá desarrollar un nuevo método para el diseño de antenas basadas en resonadores dieléctricos, DRA. Este método está basado en la formulación PMCHWT y la función de Green multicapa utilizada en el método de los momentos (MoM). A este nuevo método se le ha denominado "Substructure Characteristic Mode method", y está basado en la implementación de los complementos Schur sobre las submatrices del operador del MoM. Este estudio permite optimizar el ancho de banda de radiación de un DRA en el mismo proceso de análisis tanto para el dieléctrico como para la alimentación, como por ejemplo una ranura. Además, este método permite comprender como se comporta la ranura en presencia del resonador dieléctrico y viceversa. Este método también puede usarse para diseñar DRA usando permitividades bajas. Esto es importante en el diseño de DRA porque la alimentación perturba el sistema y produce un cambio en las resonancias de los modos característicos. Por lo tanto, al considerar la alimentación en el análisis de modos característicos se obtienen resultados más realistas comparándolos con los obtenidos mediante un análisis convencional. Así, diseñando con el "Substructure Characteristic Mode method" se pueden extraer nuevas conclusiones sobre el diseño de DRA mediante la Teoría de Modos Característicos. / En l'última dècada, la teoria dels modes característics està sent utilitzada per molts grups d'investigació en tot el món. Este tema i el seu ús en diferents dissenys d'antenes metàl·liques està creixent molt ràpid. No obstant això, la majoria de les aplicacions s'han concentrat únicament en superfícies conductores sense cap coneixement físic sobre les seues limitacions i la seua interpretació física. Pel que fa a cossos dielèctrics, no hi ha hagut tants articles publicats com en metalls. La raó és que hi ha diferents formulacions integro- diferencials i la interpretació de les seues solucions no és tan òbvia com en cossos conductors. En esta tesi es presenta una interpretació teòrica considerant cossos conductors i dielèctrics sense pèrdues. Les conclusions d'esta tesi ens permetran comprendre millor les solucions de la Teoria de Modes Característics i les seues limitacions. Açò és important en enginyeria d'antenes. Açò és important en enginyeria d'antenes. A més, esta anàlisi permetrà desenrotllar un nou mètode per al disseny d'antenes basades en ressonadors dielèctrics, DRA. Este mètode està basat en la formulació PMCHWT i la funció de Green multicapa utilitzada en el mètode dels moments (MoM) . A este nou mètode se li ha denominat "Substructure Characteristic Mode method", i està basat en la implementació dels complements Schur sobre les submatrius de l'operador del MoM. Este estudi permet optimitzar l'amplada de banda de radiació d'un DRA en el mateix procés d'anàlisi tant per al dielèctric com per a l'alimentació, com per exemple una ranura. A més, este mètode permet comprendre com es comporta la ranura en presència del ressonador dielèctric i viceversa. Este mètode també pot usar-se per a dissenyar DRA usant baixes permitivitats. Açò és important en el disseny de DRA perquè l'alimentació pertorba el sistema i produïx un canvi en les ressonàncies dels modes característics. Per tant, al considerar l'alimentació en l'anàlisi de modes característics s'obtenen resultats més realistes comparant-los amb els obtinguts per mitjà d'una anàlisi convencional. Així, dissenyant amb el "Substructure Characteristic Mode method" es poden extraure noves conclusions sobre el disseny de DRA per mitjà de la Teoria de Modes Característics. / Bernabeu Jiménez, T. (2017). Contribution to the physical interpretation of characteristic mode resonances. Application to dielectric resonator antennas [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/86177