Dans le secteur de l'agroalimentaire, l'utilisation de la RFID permet d'améliorer la sécurité des produits alimentaires tout en assurant une meilleure traçabilité et un meilleur suivi des produits. Le travail de cette thèse était principalement réalisé dans le cadre d’un projet en coopération avec plusieurs partenaires académiques et industriels dans le secteur fromager où l’objectif principal du projet était de maitriser l’ensemble des étapes de fabrication par un parfait suivi de la traçabilité des produits et un pilotage précis de l’affinage. Le travail réalisé dans cette thèse s'inscrit dans ce contexte et a comme objectif le développement de tags RFID UHF adaptés aux contraintes des produits alimentaires en assurant une double fonction: une fonction de traçabilité à identification unitaire, et ensuite une fonction de détection du degré de maturation de l'aliment par mesure indirecte de ses propriétés électromagnétiques et physico-chimiques.La première étape du projet était la caractérisation des paramètres électromagnétiques des produits alimentaires durant l’affinage afin de réaliser une conception appropriée de l'antenne du tag. En radiofréquences, c'est principalement le substrat qui dicte les propriétés électromagnétiques des composants, notamment la taille des antennes et leur diagramme de rayonnement. La connaissance de ces propriétés est indispensable afin de répondre aux exigences industrielles et d'intégrer dans de bonnes conditions les systèmes dans l'environnement applicatif. En plus, une étude de corrélation est réalisée entre la variation des propriétés diélectriques et celle des propriétés chimiques durant la période d’affinage des produits. Cette étude aide à comprendre la différence entre les différents produits et permet de déterminer les paramètres principaux à suivre durant l’affinage pour la conception du tag capteur.La deuxième étape était la conception des tags identifiants pour la traçabilité des produits alimentaires durant la procédure de fabrication. L’objectif principal est de réaliser un tag identifiant avec une performance qui répond aux besoins des fabricants dans le secteur fromager concernant la taille, la mémoire et la distance de lecture du tag tout en respectant les normes de santé au niveau d’emballage du tag ainsi que le substrat utilisé. Plusieurs configurations de tag RFID UHF étaient réalisées et testées dans un environnement industriel où les résultats obtenus montrent l’efficacité d’utiliser un système de RFID pour automatiser la traçabilité des produits dans le secteur fromager.La troisième étape concerne la conception des tags capteurs pour suivre le degré d’affinage des produits pendant la période de maturation. Une première solution, basée sur l’exploitation de l’effet de variation des propriétés diélectriques sur la distance de lecture de tag, montre un manque de performance due aux faibles variations ainsi qu’aux difficultés de mesure dans un environnement réel. Une deuxième solution basée sur la mesure de taux de dégagement des gaz durant l’affinage montre la possibilité d’estimer le degré d’affinage. Par contre, la puissance d’activation de capteur et le coût élevé ne permettent pas d’adopter cette solution. Finalement, deux solutions alternatives étaient réalisées pour mesurer l’augmentation du taux d’échapement des gaz d’une manière indirecte. La première configuration de tag capteur est basée sur le suivi du changement de dimensions du produit en utilisant un capteur résistif. D’autre part, la deuxième configuration de tag capteur est basée sur le suivi de changement de pression dans l’emballage du produit dû à la production de gaz. Les résultats obtenus montrent que ces deux configurations de tag RFID capteur peuvent offrir des solutions simples et efficaces pour le pilotage de l’affinage des produits alimentaires. / In the food sector, the use of RFID makes it possible to improve the safety of food while ensuring better traceability and better monitoring of products. The work of the thesis was mainly carried out within the framework of a project in cooperation with several academic and industrial partners in the cheese sector where the main objective of the project is to develop UHF RFID tags adapted to the constraints of food products by ensuring a dual function: a traceability function with unitary identification, and then a sensing function of cheese maturation by indirect measurement of its electromagnetic and physicochemical properties.The first step of the project was the characterization of the electromagnetic parameters of food products during ripening in order to achieve an appropriate design of the tag antenna. Knowledge of these properties is essential to meet industrial requirements and to integrate systems in right conditions. Also, a correlation study is carried out between the variation of the dielectric properties and that of the chemical properties during the period of cheese ripening. This study helps to understand the difference between cheese types and allows determining the main parameters to follow during cheese maturation for the design of the sensor tag.The second step was the design of identification tags for the traceability of food products during the manufacturing process. The primary objective is to create a UHF RFID tag with a performance that meets the needs of manufacturers in the cheese sector regarding the size, memory and reading distance while respecting the health standards at the packaging level as well as the substrate used. Several UHF RFID tag configurations were realized and tested in an industrial environment where the results obtained show the effectiveness of using an RFID system to automate the traceability of products in the cheese sector.The third step is the design of sensor tags to track the degree of maturation of products during the ripening period. A first solution, based on the exploitation of the effect of variation of the dielectric properties on the tag reading distance, shows a lack of performance due to the small variations as well as the difficulties of measurement in a real environment. A second solution based on the analysis of gas evolution rate shows the possibility of estimating the degree of cheese maturation. However, the sensor activation power and the high cost represent significant challenges and thus it was difficult to adopt this solution. Finally, two alternative solutions to measure the effect of gas evolution were presented. The idea is based on monitoring other parameters varying due to the increase of gas release during cheese maturation. The first sensor tag configuration traces the variation of product dimension due to maturation using a resistive sensor. On the other hand, the second sensor tag configuration measures the change of pressure inside the product packaging due to gas production. The results obtained show that these two sensor RFID tag configurations can offer simple and practical solutions for controlling the cheese ripening process.

Presented is a radiometric sensor and associated electromagnetic propagation models, developed to facilitate non-invasive core body temperature extraction. The system has been designed as a close-proximity sensor to detect thermal emissions radiated from deep-seated tissue 1 cm – 3 cm inside the human body. The sensor is intended for close proximity health monitoring applications, with potential implications for deployment into the improved astronaut liquid cooling garment (LCG). The sensor is developed for high accuracy and resolution. Therefore, certain design issues that distort the close proximity measurement have been identified and resolved. An integrated cavity-backed slot antenna (CBSA) is designed to account for antenna performance degradation, which occurs in the near field of the human body. A mathematical Non-Contact Model (NCM) is subsequently used to correlate the observed brightness temperature to the subsurface temperature, while accounting for artifacts induced by the sensor’s remote positioning from the specimen. In addition a tissue propagation model (TPM) is derived to model incoherent propagation of thermal emissions through the human body, and accounts for dielectric mismatch and losses throughout the intervening tissue layers. The measurement test bed is comprised of layered phantoms configured to mimic the electromagnetic characteristics of a human stomach volume; hence defines the human core model (HCM). A drop in core body temperature is simulated via the HCM, as the sensor monitors the brightness temperature at an offset distance of approximately 7 mm. The data is processes through the NCM and TPM; yielding percent error values < 3%. This study demonstrates that radiometric sensors are indeed capable of subsurface tissue monitoring from the near field of the body. However, the following components are vital to achieving an accurate measurement, and are addressed in this work: 1) the antenna must be designed for optimum functionality in close proximity to biological media; 2) a multilayer phantom model is needed to accurately emulate the point of clinical diagnosis across the tissue depth; 3) certain parameters of the non-contact measurement must be known to a high degree of accuracy; and 4) a tissue propagation model is necessary to account for electromagnetic propagation effects through the stratified tissue.

Because of the tremendous amount of media streaming, video calling and high definition TV and gaming, the biggest challenge for the wireless industry is the increasing demand of high data rates. Utilization of mm-wave frequencies is an attractive option to meet this high demand. Recent advances in low cost semiconductor technologies allow realization of low-cost on-chip RF front-ends in the high millimeter wave (mm-wave) frequencies, making it possible to realize compact systems for these application areas. Although integrated circuits (ICs) are one of the main building blocks of a mm-wave system, in order to realize a fully functional wireless system, cost-effective antenna design and packaging are two important pre-conditions. Researchers have investigated and reported low-cost electronics packaging up to 100 GHz to a great extent on ceramic substrates, but mm-wave packaging above 100 GHz is relatively less explored, particularly on organic substrates. This Ph.D. dissertation demonstrates the design and development of microwave and mm-wave on-chip and on-package antennas and organically packaged components and modules ranging from 20 GHz to 170 GHz. The focus of this research was to design and develop mm-wave components and modules on LCP, to investigate the viability of this organic substrate and development of fabrication techniques in the K- (18-26.5 GHz), V- (50 to 70 GHz), W- (75 to 110 GHz), and D- (110 to 170 GHz) bands. Additionally, a demonstration of a micro-machined on-chip antenna has also been presented. This dissertation is divided in three parts: (1) characterization of liquid crystal polymer from 110 to 170 GHz. (2) development of highly radiation efficient on-chip and AiP antennas, and (3) development of mm-wave modules with the integration of antennas.

Orientadores: Fernando Jose Von Zuben, Cynthia Cristina Martins Junqueira / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-08T19:03:06Z (GMT). No. of bitstreams: 1 Barra_TiagoVenturieri_M.pdf: 6614671 bytes, checksum: 4facb72e441f3af7afdbfc42f31ca50b (MD5) Previous issue date: 2007 / Resumo: O estudo de antenas de micro?ta envolve a especi?cação de um amplo espectro de parâmetros físicos, e cada proposta de antena requer o emprego de algoritmos avançados de cálculo numérico para medidas de desempenho, como impedância de entrada, padrão de irradiação e ganho em faixas especí?cas de freqüência. O principal objetivo desse trabalho é desenvolver um ambiente computacional combinando um software de análise de estruturas eletromagnéticas, MStrip40, baseado no método dos momentos (MoM), e um método de busca evolutivo, denominado algoritmo genético. Buscam-se valores ótimos de parâmetros físicos de antenas de micro?ta, como comprimento e largura do elemento irradiador e da linha de alimentação, entre outros. São tratados vários tipos de antenas de micro?ta, e um elenco amplo de critérios de desempenho é considerado, mantendo sempre um valor baixo para o coe?ciente de onda estacionária na freqüência de projeto. A validação dos resultados gerados pelo ambiente computacional é alcançada através da fabricação da melhor antena obtida em cada caso de estudo, seguida por testes de desempenho do dispositivo físico fabricado, realizados em laboratórios especializados / Abstract: The study of microstrip antennas involves the speci?cation of a broad spectrum of physical parameters, and each antenna proposal requires the use of advanced algorithms of numerical calculus to measure the performance, such as input impedance, radiation pattern and gain in speci?c frequency bands. The main objective here is to develop a computational environment joining a software for electromagnetic structure analysis, called MStrip40 and based on the Method of Moments (MoM), together with an evolutionary search method founded on a genetic algorithm. The outcome is composed of optimal values for physical parameters of the microstrip antenna, such as length and width of the radiator element and of the feeding line. Several kinds of microstrip antennas are treated, and a wide range of performance criteria are considered, always keeping a low value for the coef?cient of stationary wave at the design frequency. The validation of the results produced by the computational environment is achieved by means of the manufacture of the best obtained antenna in each case study, followed by performance evaluation of the manufactured physical device, which is accomplished in dedicated laboratories / Mestrado / Engenharia de Computação / Mestre em Engenharia Elétrica

In this master thesis, compact antenna design aimed towards naval applicationshave been designed, analyzed and evaluated. There is a recentinterest in the development of compact antennas to be used for smallersubmarine models, and with a smaller hull on a submarine, communicationand antenna systems must be adapted and minimized, which limitsantenna design. With two limiting cylindrical volumes with maximumallowed dimensions r = 10 cm, h = 50 cm and r = 5 cm, h = 90 cm,the antennas would operate on the upper to lower V/UHF band, radiatehemispherically and have a high RHCP purity. It was found that the mostappropriate antenna structure for both volumes was QHA design. Afterthe design and analysis process was completed, it was concluded that theshorter antenna design could meet all requirements set while the longerantenna design did not meet all requirements but could still establish agood communication link on the higher frequencies. Antenna prototypesbased on the produced design were constructed and measured and, despiteminor deviations, veried that the results obtained from this thesis werereliable. / I denna mastersuppsatsen har kompakta antenner riktade mot marinaapplikationer designats, analyserats och utvarderats. Det nns ett intressefor utvecklingen av kompakta antenner som ska anvandas for mindreubatsmodeller och med ett mindre skrov pa en ubat maste kommunikationsochantennsystemen anpassas och minimeras darefter, vilket begransarantenndesignen. Med tva begransande cylindriska volymer med maximalttillatna dimensioner r = 10 cm, h = 50 cm samt r = 5 cm,h = 90 cm, skulle antennerna verka pa det ovre till lagre V/UHF-bandet,strala hemisfariskt och ha en hog RHCP-renhet. Det konstaterades attden lampligaste antennstrukturen for bada volymen var QHA-design. Efteratt design- och analysprocessen slutforts drogs slutsatsen att den kortareantenndesignen kunde uppfylla alla krav som stalldes medan den langreantenndesignen inte uppfyllde alla krav men fortfarande kunde upprattaen bra kommunikationslank pa de hogre frekvenserna. Antennprototyperbaserade pa de framtagna designerna konstruerades och mattes och, trotsmindre avvikelser, verierade att de erhallna resultaten fran denna avhandlingvar tillforlitliga.

No description available.

La technologie d'identification par radiofréquence (RFID) a eu un essor très important ces dernières années notamment grâce à sa configuration polyvalente et aux innombrables possibilités d'intégration offertes par cette technologie notamment avec l'apparition d'un nouveau contexte applicatif celui des objets connectés. Depuis quelques années, des applications de la RFID UHF en champ proche ont été notamment développées afin de surmonter les problèmes liés à la dégradation de lecture des tags lorsqu'ils sont placés dans des milieux fortement perturbateurs. Les travaux de recherche présentés dans cette thèse s'intéressent à l'étude de la technologie RFID UHF en zones de champ proche et de champ lointain. Les études portent plus particulièrement sur la conception d'antennes lecteur et d'antennes tag ainsi que sur les méthodes de caractérisation des systèmes RFID en zones de champ proche et de champ lointain. Une étude sur les caractéristiques des champs rayonnées par une antenne est réalisée afin de souligner les critères les plus pertinents en vue de concevoir des antennes pour les lecteurs RFID, performantes en zone de champ proche. A partir de l'état de l'art sur les antennes tags et les méthodologies de conception classiques, une nouvelle approche de conception est développée qui vise à améliorer la conception d'antennes tags en intégrant une vision appropriée pour tenir compte du niveau de puissance espéré dans une application donnée. Enfin avec pour objectif la caractérisation des tags RFID UHF, d'une part une approche est proposée permettant l'identification de familles de tags, et d'autre part, une procédure innovante pour la mesure de l'efficacité du transfert de puissance est proposée et validée expérimentalement. / The Radiofrequency Identification technology (RFID) has had a huge growth these last years, due to its versatility and the uncountable possibilities to integrate this technology in many different application (tracking and inventory of goods, access control, supply chain, etc.), and in particular the brand new context of internet of things projects. For some years, the near field UHF RFID applications has been developed in order to overcome the problems related to degradations of tag's read range when needing to use it in a perturbing environment. The research work presented in this thesis come as a study of the UHF RFID in near field and far field zones. This study focus more particularly on the design of reader and tag antennas and on the characterization method in near field and far field zones. A study on the characteristics of fields outgoing from an antenna has been made, in order to underline the important criteria for the design of performant UHF RFID reader antennas in near field zone. From the state of art about tag antennas design and classical methodologies, we propose a new approach that aims improving the design of tag antennas in a more suitable point of view that is getting the expected power level in a given application. Finally, with an objective to characterize UHF RFID tags, we first propose a new approach enabling the identification of tag families, and then propose a new innovating power transfer efficiency measurement procedure, that has been validated experimentally.

Fundamental features of Radio Frequency Identification (RFID) systems used in different application areas will be reviewed. Techniques used in realizing RFID antenna systems will be studied and the procedure to realize a specific RFID antenna type possessing desired characteristics will be described. Electrical properties such as radiation pattern, impedance will be predicted using analytical and/or computer simulation techniques. Experimental investigations will be carried out to complement the theoretical work.

Made available in DSpace on 2014-12-17T14:56:06Z (GMT). No. of bitstreams: 1 SinaraRM_DISSERT.pdf: 1037040 bytes, checksum: 9dd71f16b45358e60b8b82862adaafc6 (MD5) Previous issue date: 2012-08-15 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This paper presents an evaluative study about the effects of using a machine learning technique on the main features of a self-organizing and multiobjective genetic algorithm (GA). A typical GA can be seen as a search technique which is usually applied in problems involving no polynomial complexity. Originally, these algorithms were designed to create methods that seek acceptable solutions to problems where the global optimum is inaccessible or difficult to obtain. At first, the GAs considered only one evaluation function and a single objective optimization. Today, however, implementations that consider several optimization objectives simultaneously (multiobjective algorithms) are common, besides allowing the change of many components of the algorithm dynamically (self-organizing algorithms). At the same time, they are also common combinations of GAs with machine learning techniques to improve some of its characteristics of performance and use. In this work, a GA with a machine learning technique was analyzed and applied in a antenna design. We used a variant of bicubic interpolation technique, called 2D Spline, as machine learning technique to estimate the behavior of a dynamic fitness function, based on the knowledge obtained from a set of laboratory experiments. This fitness function is also called evaluation function and, it is responsible for determining the fitness degree of a candidate solution (individual), in relation to others in the same population. The algorithm can be applied in many areas, including in the field of telecommunications, as projects of antennas and frequency selective surfaces. In this particular work, the presented algorithm was developed to optimize the design of a microstrip antenna, usually used in wireless communication systems for application in Ultra-Wideband (UWB). The algorithm allowed the optimization of two variables of geometry antenna - the length (Ls) and width (Ws) a slit in the ground plane with respect to three objectives: radiated signal bandwidth, return loss and central frequency deviation. These two dimensions (Ws and Ls) are used as variables in three different interpolation functions, one Spline for each optimization objective, to compose a multiobjective and aggregate fitness function. The final result proposed by the algorithm was compared with the simulation program result and the measured result of a physical prototype of the antenna built in the laboratory. In the present study, the algorithm was analyzed with respect to their success degree in relation to four important characteristics of a self-organizing multiobjective GA: performance, flexibility, scalability and accuracy. At the end of the study, it was observed a time increase in algorithm execution in comparison to a common GA, due to the time required for the machine learning process. On the plus side, we notice a sensitive gain with respect to flexibility and accuracy of results, and a prosperous path that indicates directions to the algorithm to allow the optimization problems with "&#951;" variables / Este trabalho apresenta um estudo avaliativo dos efeitos da utiliza??o de uma t?cnica de aprendizado de m?quina nas caracter?sticas principais de um algoritmo gen?tico (GA) multiobjetivo e auto-organiz?vel. Um GA t?pico pode ser visto como uma t?cnica de busca que ? normalmente aplicada em problemas que envolvem complexidade n?o polinomial. Originalmente, estes algoritmos foram idealizados para criar m?todos que buscam solu??es aceit?veis para problemas em que os ?timos globais s?o inacess?veis ou s?o de dif?cil obten??o. A princ?pio, os GAs consideravam apenas uma fun??o de avalia??o e um ?nico objetivo de otimiza??o. Hoje, entretanto, s?o comuns as implementa??es que consideram diversos objetivos de otimiza??o simultaneamente (algoritmos multiobjetivos), al?m de permitir a altera??o de diversos componentes do algoritmo dinamicamente (algoritmos autoorganiz?veis). Ao mesmo tempo, s?o comuns tamb?m as combina??es dos GAs com t?cnicas de aprendizado de m?quina para melhorar algumas de suas caracter?sticas de desempenho e utiliza??o. Neste trabalho, um GA com recursos de aprendizado de m?quina foi analisado e aplicado em um projeto de antena. Utilizou-se uma t?cnica variante de interpola??o bic?bica, denominada Spline 2D, como t?cnica de aprendizado de m?quina para estimar o comportamento de uma fun??o de fitness din?mica, a partir do conhecimento obtido de um conjunto de experimentos realizados em laborat?rio. Esta fun??o de fitness ? tamb?m denominada de fun??o de avalia??o e ? respons?vel pela determina??o do grau de aptid?o de uma solu??o candidata (indiv?duo) em rela??o ?s demais de uma mesma popula??o. O algoritmo pode ser aplicado em diversas ?reas, inclusive no dom?nio das telecomunica??es, como nos projetos de antenas e de superf?cies seletivas de frequ?ncia. Neste trabalho em particular, o algoritmo apresentado foi desenvolvido para otimizar o projeto de uma antena de microfita, comumente utilizada em sistemas de comunica??o sem fio e projetada para aplica??o em sistemas de banda ultra larga (Ultra-Wideband - UWB). O algoritmo permitiu a otimiza??o de duas vari?veis da geometria da antena - o Comprimento (Ls) e a Largura (Ws) de uma fenda no plano de terra com rela??o a tr?s objetivos: largura de banda do sinal irradiado, perda de retorno e desvio da frequ?ncia central. As duas dimens?es (Ls e Ws) s?o usadas como vari?veis em tr?s distintas fun??es de interpola??o, sendo uma Spline para cada objetivo da otimiza??o, para compor uma fun??o de fitness agregada e multiobjetiva. O resultado final proposto pelo algoritmo foi comparado com o resultado obtido de um programa simulador e com o resultado medido de um prot?tipo f?sico da antena constru?da em laborat?rio. No estudo apresentado, o algoritmo foi analisado com rela??o ao seu grau de sucesso, no que diz respeito a quatro caracter?sticas importantes de um GA multiobjetivo auto-organiz?vel: desempenho, flexibilidade, escalabilidade e exatid?o. Ao final do estudo, observou-se na compila??o do algoritmo um aumento no tempo de execu??o em compara??o a um GA comum, por conta do tempo necess?rio para o processo de aprendizagem. Como ponto positivo, notou-te um ganho sens?vel com rela??o a flexibilidade e a exatid?o dos resultados apresentados, al?m de um caminho pr?spero que indica dire??es para permitir com que o algoritmo permita a otimiza??o de problemas com &#951; vari?veis

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 no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/86177 / TESIS