A inoculação de sementes de leguminosas de grãos tais como soja [Glycine max. (L.)], feijão (Phaseolus vulgaris L.) e pastagens tem sido uma estratégia efetiva e conveniente para introduzir estirpes eficientes de Bradyrhizobium/Rhizobium em solos agrícolas sem histórico de cultivo anterior dessa cultura ou quando as estirpes ivas são ineficientes no processo biológico de aquisição de nitrogênio. Através do uso de substrato turfoso previamente esterilizado como veículo da bactéria, os efeitos ambientais adversos podem ser amenizados, pois este substrato atua diretamente, na sobrevivência da bactéria através do fornecimento de nutrientes. O Brasil requer que os substratos turfosos sejam pré-esterilizados através de radiação gama de cobalto-60 (60Co), sendo recomendada a dose de 50 kGy para uma efetiva eliminação de patógenos e saprófitas, que podem competir com a bactéria introduzida. Recentemente, a utilização de aceleradores de elétrons foi considerada uma nova alternativa de radiação para pré-esterilização da turfa, pois, por se constituir de processo oxidativo avançado, gera radicais altamente reativos, eficientes na eliminação de agentes contaminantes. Esta técnica é considerada ecologicamente mais segura que a radiação gama, além de ser um processo mais rápido. Há, porém, a característica de ter menor profundidade de penetração da radiação em relação ao 60Co. O presente estudo comparou o método usando doses crescentes de radiação gama por 60Co e por feixe de elétrons (0, 10, 20, 30, 40 e 50 kGy). Os dados experimentais (7, 14, 21 e 28 dias para a fase curta e 150, 180 e 210 dias para a fase longa de incubação) mostraram um elevado número de células da bactéria Rhizobium tropici CM-01 gusA+ inoculada em substratos turfosos submetidos aos dois processos de esterilização, sendo que ambos processos atenderam aos padrões mínimos requeridos pelas normas brasileiras (validade de 180 dias e presença acima de 1 x 108 células/g de substrato). Sob doses mais elevadas, acima de 40 kGy, o método por feixe de elétrons foi mais eficiente em eliminar actinobactérias, consideradas sérias antagonistas de bactérias inoculantes em turfas e que surgiram após 150 dias. Em um segundo estudo, usando o isolado CM-01 celB+ por um período de 30 dias, os resultados confirmaram a eficiência do método por feixe de elétrons na fase de crescimento bacteriano, mesmo para dose baixa de 10 kGy. / Inoculation of root nodule bacteria into legume seeds such as soybean [Glycine max. (L.)], common bean (Phaseolus vulgaris L.) and forrage pasture has been effective and convenient as this simple procedure may introduce effective strains of Bradyrhizobium/Rhizobium into agricultural soils without a past history of successful cropping systems with the legume hosts. Peat-based substrates previously sterilized have been used for decades as bacteria carrier, protecting them from the prevailing harsh conditions in tropical soils and ensuring their survival with nutrient and protection against the soil antagonists. The Brazilian Government requires that all peat-based substrates must be gamma-sterilized from a cobalt-60 (60Co) source, prior the introduction of the root nodule bacteria into the package. The recommendation is for a dose up to 50 kGy for an effective suppression of pathogens and saprophytes, in order to avoid competition among the substrate microbiota. Recently, the use of the electron beam (EB) accelerator has shown to be a new alternative for peat pre-sterilization, as this technique may promote reactive free-radicals which are efficient to suppress microbial contaminants. This fast technology is considered more environment and ecology friendly-sound than gamma radiation (γ). The disvantage of not reaching higher depth than gamma rays from 60Co must be considered, and attempts of optimizing the technique are crucial. This study compared both methods by using increasing rates of radiation by 60Co by the EB method - 0, 10, 20, 30, 40 e 50 kGy in a commercial peat used for inoculants. Experimental data from days 7, 14, 21 and 28 days (growth period) and 150, 180 and 210 days (storage period) indicated high numbers of the strain Rhizobium tropici CM-01, labelled with gusA+ (Study 1) and celB+ (Study 2) from both eat-sterilizing techniques, reaching values above the minimum of 1x108 cells g-1 peat. At high rates, above 40 kGy, and after long incubation periods (ex. after 150 days), EB method was more efficient to suppress actinobacteria, one serious antagonist for rhizobia. Strain CM-01 celB+, data for the period of bacterial growth confirmed the efficiency of the method even at rates as low as 10 kGy.

O uso de madeira laminada colada (MLC) em países da América do Norte e Europa é bastante difundido. No Brasil, apesar da técnica existir desde o século XX, a sua utilização é incipiente em relação à possibilidade de utilização desse produto. O desenvolvimento de produtos a partir de lâminas de madeira com pequenas dimensões se deve à necessidade de se eliminar defeitos nas peças estruturais, tais como nó e medula, os quais reduzem significativamente as características de resistência e elasticidade da peça, em comparação com a madeira sã. O aumento da resistência e da rigidez da viga de MLC pode ser conseguido por meio da classificação das lâminas, seguida de uma disposição adequada das mesmas. Outra maneira de se obter um aumento nas propriedades de rigidez e de resistência de elementos estruturais de MLC é a utilização de polímeros reforçados com fibras (PRF) na região mais tracionada da viga. Esta providência, além de melhorar as propriedades mecânicas do elemento estrutural, aumenta a confiabilidade em relação ao modo de ruptura. Dentro deste escopo, este trabalho procura estabelecer critérios para fabricação de vigas retas de MLC, sem e com reforço de fibras de vidro, a partir de informações obtidas na revisão bibliográfica, abordando aspectos relacionados à resistência da madeira (espécie e qualidade da madeira, quantidade de nós, inclinação das fibras em relação ao eixo longitudinal das peças, presença de medula), dimensões das lâminas, espaçamento mínimo entre emendas dentadas de uma mesma lâmina e posicionamento das emendas dentadas na viga, colagem e prensagem. Foi proposto um modelo numérico para cálculo do momento fletor resistente e da rigidez à flexão (EI) de vigas de MLC sem reforço e reforçadas com PRF. O modelo admite a validade da hipótese de distribuição linear de deformações ao longo da altura da viga, comportamento elásto-frágil-linear da madeira na tração paralela às fibras e bi-linear na compressão paralela às fibras. Este modelo foi implementado a um programa computacional que por meio de um processo interativo determina o valor do momento fletor resistente e da rigidez à flexão. Resultados experimentais obtidos por meio de ensaios em vigas de MLC reforçadas com fibra de vidro indicam a validade do modelo teórico proposto. Também foram realizados ensaios de delaminação para avaliar a eficiência dos adesivos Phenol-resorcinol e Epóxi AR-300 quando submetidos a variação de temperatura, umidade e pressão. Resultados obtidos indicaram a eficiência destes adesivos. / Glulam beam is used in countries of North America and Europe. In Brazil, the technique exists since the 20th Century, but its use is incipient in relation to the possibility of the product. The development of products that use wood with small dimensions is important to eliminate defects in the structural pieces, such as knot and marrow, which reduce the strength and stiffness of the piece. The increase of the strength and stiffness of the glulam beam can be achieved through the classification of the lumber, or by an appropriate disposition of the lumber. Another way to obtain an increase in the strength and stiffness of the glulam beam it is the use of fiber reinforced polymers (FRP). This way, besides improving the mechanical properties of the structural element, increases the reliability in relation to the rupture way. This work establish criteria for production of glulam beams, without and with reinforce of glass fiber, starting from information obtained in the bibliographical revision, approaching aspects related to the straight of the wood (species and quality of the wood, inclination of the fibers in relation to the longitudinal axis of the pieces, marrow presence), dimensions of the sheets, minimum spacing between bitten amendments of a same sheet and positioning of the jagged amendments in the beam. A numeric model for calculation of the straight moment and flexural stiffness (EI) of glulam beams was proposed. The model admits the validity of the hypothesis of lineal distribution of deformations along the height of the beam, elastic-fragile-lineal behavior of the wood in the parallel traction and bi-lineal in the parallel compression of the fibers. This model was implemented in a computer program that uses an interactive process to determine the value of the straight moment and of the flexural stiffness. Experimental results obtained indicate the validity of the theoretical model proposed. A test of delamination was done to evaluate the efficiency of the adhesives Phenol-resorcinol and Epoxy AR-300 when submitted to temperature, humidity and pressure variation. Results indicated the efficiency of these adhesives.

A demanda por qualidade nas aplicações envolvendo radiação laser exigiu melhorias no seu desempenho. Conseqüentemente, equipamentos mais rápidos e precisos nas medidas dos seus parâmetros são indispensáveis. Nas áreas onde o laser é empregado, três parâmetros sobressaem-se nas suas aplicações: (1) potência ou energia, (2) freqüência e (3) comprimento espacial ou largura do feixe. A determinação das bordas, isto é, da largura do feixe, está ligada a um percentual do máximo valor atingido pela energia. O diâmetro do feixe, juntamente com a energia, determina-se a densidade do feixe. Outros parâmetros como: divergência e fator de qualidade (M2), podem ser determinados também. O presente trabalho busca desenvolver um sistema de translação bidimensional que possa ser empregado na caracterização espacial do feixe de lasers. Para determinar o perfil do feixe de lasers utiliza-se o método borda-da-lâmina (knife-edge), relacionando o deslocamento da lâmina posicionada transversalmente ao feixe, com a energia transmitida. Obstruindo o feixe com uma lâmina opaca, obtêm-se a variação da energia do feixe em função da posição da lâmina. Esta variação representa a integral do perfil Gaussiano do feixe. Para a automação do sistema foi empregado o programa Labview (National Instruments). O funcionamento do protótipo mostrou-se eficiente na caracterização de feixes laser e com uma instrumentação de baixo custo para a comercialização nacional. No entanto, apresentou-se lento na aquisição de dados, tornando a tarefa de caracterização do laser mais demorada. Fatores como velocidade do motor de passo e linguagem de programação contribuíram para tornar a aquisição lenta. / The demand for quality in the applications involving laser radiation demanded improvements in its performance. Faster equipments in the measures of its parameters are indispensable. In the areas where the laser is employee, three parameters are important in its applications: (1) power or energy, (2) frequency and (3) beam spatial. The determination of the edges, i. e., the width of the beam, is correlated to a percentage of the maximum reached energy. This parameter, together with the energy, determines beam density; beyond this parameter it also possible to determine the divergence and quality factor (M2). This work searches to develop a system of bi-dimension translation that can be used in the spatial characterization of laser beam. To determine the profile of laser beam it is used the knife-edge method, that it relates the displacement of the blade located transversally to the beam, with the transmitted energy. Blocking the beam with a blade the energy variation of the beam is correlated with blade position; this variation represents the integral of the beam Gaussian profile. For the automation it will be used the Labview program(National Instruments). The prototype had showed to be efficient in the characterization of laser beams and a low cost for national commercialization; however was slow in the data acquisition resulting a longer time to acquire the laser parameters. Instrumental components as step motors or programming language had contributed to slowly acquisition.

Este trabalho fornece uma visão geral sobre a aplicação, o dimensionamento e o detalhamento de elementos fletidos de concreto de alto desempenho (CAD), armados ou protendidos, com particular atenção para estes últimos. Procurou-se, sempre que possível, realçar as situações nas quais os atuais procedimentos normalizados permanecem válidos, ou não, para o cálculo das vigas de CAD. Na introdução, apresenta-se a viabilidade econômica da aplicação do concreto de alto desempenho nas vigas. No capítulo referente à retração e à fluência, abordam-se procedimentos válidos para o CAD, os quais apresentam melhor correlação com os resultados experimentais que a obtida através do ACI 209 (1982) ou do CEB-FIP (1990). No que se refere à flexão, apresenta-se um diagrama tensão-deformação retangular, e comparam-se os seus resultados para concretos usuais e de alto desempenho, com os obtidos pelo diagrama parábola-retângulo, em termos de consumo de armadura. No capítulo referente ao cisalhamento, apresentam-se recomendações para a utilização do Método Padrão e do Modelo de Treliças de Diagonais de Inclinação Variável para o cálculo da armadura transversal em vigas de CAD. Para o cálculo dos deslocamentos causados por ações de curta duração, confirma-se a validade da metodologia de Branson para as vigas de CAD. Os deslocamentos adicionais causados por ações de longa duração também são considerados, incluindo-se metodologias para as vigas de concreto armado e para as pré-moldadas protendidas. Exemplos de dimensionamento são feitos para todos os itens apresentados, considerando-se uma viga pré-moldada de 30 m de comprimento, seção \"T\", com pós-tensão e fck = 70 MPa. / This work provides an overview of use and design of the high performance concrete (HPC) flexural members, reinforced or prestressed, with particular attention for the last ones. Cases in which procedures of the modern codes for calculation of HPC beams remain valid were enhanced. In the introduction, the economic viability of high performance concrete beams is presented. In the chapter about shrinkage and creep, valid procedures for HPC are presented. These procedures have better correlation with the actual results than those relative to ACI 209 (1982) or CEB-FIP (1990). A rectangular stress block is presented, and its results for usual and high performance concrete are compared with those from the parabolic-rectangular stress block, in terms of consume of steel. In the chapter about shear, recommendations for use of Standard Method and Variable Angle Truss Model for HPC beams are presented. For the calculation of short term deflections, the validity of Branson\'s Method for high performance concrete beams is confirmed. Sustained load deflections are also considered, and including procedures for reinforced beams and for precast prestressed ones. For all the considered topics, examples are presented for a 30 m span precast post-tensioned beam, \"T\" cross section and fck = 70 MPa.

Although the Maxwell equations govern the propagation of EM waves at all frequencies, the methods required to generate, direct, analyse and detect radiation differ from band to band. This thesis is concerned with the development and demonstration of 'Quasi-optical' techniques for millimetre wavelengths, which involve the propagation of Gaussian profiled beams a few wavelengths across, and the realization of a general circuit approach to mm-wave measurement. Gaussian beam-mode analysis, which is used in later chapters to understand propagation of quasi-optical beams, is reviewed in chapter 1. Chapter 2 outlines the design, manufacture and testing of corrugated feed horns which generate fundamental Gaussian beam-modes. The design and manufacture of lenses which control the spreading of the beams and directional couplers which provide desirable signal processing functions in quasi-optical circuits is discussed in chapter 3. Chapter 4 traces the development of a Faraday isolator which operates in free-space and can suppress unwanted reflections in quasi-optical circuits. Chapter 5 discusses a reusable circuit board upon which systems can be easily and quickly constructed. A null reflectometer built using quasi-optical components is outlined in chapter 6 and reflection measurements from lenses and horns presented. Chapter 7 describes a corrugated feed horn/lens antenna used in a balloon-borne nw-wave cosmic background experiment. Finally, Chapter 8 demonstrates the use of quasi-optical components in a 115 GHz receiver circuit.

The objectives of this thesis were to develop a methodology for the measurement of laser beam characteristics from a single cavity laser and to establish a preliminary guideline that would determine which crystals were acceptable for use in production of laser devices. These objectives were achieved by developing the experimental procedures and by statistical analysis of the data obtained. However, additional future work is needed to independently confirm the results of this thesis. Efficient and reliable operation of a lamp-pumped Nd:YAG laser is highly dependent on the crystal from which the beam is derived. However little attention is given to the quality of the laser beam produced by each crystal. Although many factors influence the output beam, the power dependent focal length is of particular importance. Unfortunately, direct measurement of the crystal focal length is not possible with a Nd:YAG laser beam. This is because the single cavity laser functions as both a resonator and amplifier simultaneously. Therefore, a method was developed that measured the caustic of the laser beam after it had emerged from the resonator and been focused by means of a focusing element. The caustic of the beam was analyzed utilizing a beam analyzer that calculated the beam focusability factor and the beam waist size. From this information, the waist diameter at the outcoupler mirror was calculated using Gaussian beam propagation principles. A resonator model was developed based on the self-repeating ABCD matrix that allowed for the determination of the induced thermal lens based on the input power. Several approaches to model the thermal lensing effect were taken, each with increasing complexity. As a result, three parameters were evaluated with the intention of using one or more as a means to classify good and bad crystals. They were the crystal sensitivity factor, the beam focusability factor, and the beam waist size at the measurement plane. Calculation of the crystal sensitivity factor, M^-1, was based on the developed resonator model and numerous approximations of the crystal behavior. Thus, after calculating the M-1 factor as a function of input power, no distinguishable pattern was seen. However, the beam focusability factor and the beam size, both showed distinct regions that separate good and bad crystals. Statistical analysis performed on the data supports a preliminary conclusion that these two parameters may be used as a quality control measure. These parameters are measured using existing internationally accepted procedures and are therefore the best currently available tools for determination of the quality of Nd:YAG crystals.

Terahertz (THz) technologies have numerous applications such as biological and medical imaging, security screening, remote sensing, and industrial process control. However, the lack of practical THz sources and detectors is still a significant problem limiting the impact of these applications. In this Thesis work, three novel THz radiation mechanisms are proposed and investigated, based on the distinctive electronic properties of charge carriers in 2D single-layer graphene and related 1D conductors (i.e., graphene nanoribbons and carbon nanotubes), combined with the use of nanoscale dielectric gratings. Numerical simulations as well as fabrication and characterization activities are carried out. The first proposed radiation mechanism is based on the mechanical corrugation of a single-layer sheet of graphene or 1D carbon conductor, deposited on a lithographically-defined sinusoidal grating. In the presence of a dc voltage, carriers will therefore undergo periodic angular motion and correspondingly radiate (similar to cyclotron emission but without the need for any external magnetic field). My numerical simulations indicate that technologically significant output power levels can correspondingly be obtained at geometrically tunable THz frequencies. Initial graphene samples on sinusoidal gratings were fabricated and found to undergo significant strain redistribution, which affects their structural quality. Charge carriers moving in a flat sheet of graphene or linear 1D carbon conductor parallel to a nanoscale grating can also produce THz radiation based on the Smith-Purcell effect. The role of the grating in this case is to diffract the evanescent electromagnetic fields produced by the moving electrons and holes so that THz light can be radiated. Once again, numerical simulations indicate that this approach is promising for the realization of ultra-compact THz sources capable of room-temperature operation. Initial experimental results with ultra-high-mobility graphene samples embedded in boron nitride films show promising THz electroluminescence spectra. The last approach considered in this Thesis involves graphene plasmons at THz frequencies, which can be excited through the decay of hot electrons injected with an applied bias voltage. A nearby grating can then be used to outcouple the guided electromagnetic fields associated with these collective charge oscillations into radiation. The excitation of these THz plasmonic resonances at geometrically tunable frequencies has been demonstrated experimentally via transmission spectroscopy measurements. / 2017-06-21T00:00:00Z

No description available.

The total wind power capacity installed in the world has substantially grown during the last few years, mainly due to the increasing number of horizontal axis wind turbines (HAWT). Consequently, a big effort was employed to increase HAWT\'s power capacity, which is directly associated to the size of blades. Then, novel designs of blades may lead to very fexible structures, susceptive to large deformation, not only during extreme events, but also for operational conditions. In this context, this thesis aims to compare two geometrically nonlinear structural modeling approaches that handle large deformation of blade structures: 3D geometrically-exact beam and shell finite element models. Regarding the beam model, due to geometric complexity of typical cross-sections of wind turbine blades it is adopted a theory that allows creation of arbitrary multicellular cross-sections. Two typical blade geometries are tested, and comparisons between the models are done in statics and dynamics, always inducing large deformation and exploring the accuracy limits of beam models, when compared to shells. Results showed that the beam and shell models present very similar behavior, except when violations occur on the beam formulation hypothesis, such as when shell local buckling phenomena takes place. / A capacidade total de energia eólica instalada no mundo cresceu substancialmente nos últimos anos, principalmente devido ao número crescente de turbinas eólicas de eixo horizontal. Consequentemente, um grande esforço foi empregado com o intuito de aumentar a capacidade de produção das turbinas eólicas, que está diretamente associada ao tamanho das pás. Assim, surgiram projetos inovadores quanto à concepção de pás de turbinas eólicas levando a estruturas bastante flexíveis, susceptíveis a grandes deslocamentos, não apenas em eventos extremos, mas também em condições normais de operação. Nesse contexto, a presente dissertação tem por objetivo comparar duas abordagens de modelos estruturais geometricamente não-lineares capazes de lidar com grandes deslocamentos de pás de turbinas eólicas: elementos finitos geometricamente exatos 3D de vigas e cascas. Em relação ao modelo de viga, devido à complexidade geométrica das seções transversais típicas de pás de turbinas eólicas, adota-se uma teoria que permite a criação de seções transversais arbitrárias multicelulares. Duas geometrias de pás s~ao testadas e comparações entre os modelos s~ao feitas em análises estáticas e dinâmicas, sempre induzindo grandes deslocamentos e explorando os limites de precisão do modelo de viga, quando comparado ao modelo de cascas. Os resultados indicam que os modelos de viga e casca apresentam comportamento muito similar, exceto quando ocorrem violações em hipóteses do modelo de viga, tal como quando ocorre flambagem local do modelo de casca.

L'évolution des technologies numériques a permis l'introduction d'objets connectés dans le quotidien d'une grande partie de la population mondiale. Face à une demande de données sans-fil toujours croissante, des techniques nouvelles doivent être employées pour offrir un débit plus élevé à des appareils moins volumineux et accessibles à un prix raisonnable. Les antennes constituent l'organe central de toutes les télécommunications et elles jouent un rôle majeur dans l'évolution vers des systèmes plus performants. En effet, l'augmentation du débit de données passe par une augmentation du gain et de la bande de fonctionnement, et plus une antenne est directive plus son intégration est complexe. La tendance actuelle est à l'évolution vers les bandes de fréquences millimétriques, ce qui permet une réduction du volume de l'antenne et l'utilisation de bandes de fréquences plus larges, néanmoins la fabrication est un vrai défi technologique. Les travaux de recherches effectués au cours de cette thèse portent sur la conception d'antennes pour une application de lien backhaul : une liaison en bande E (71-86GHz) entre deux antennes fixes utilisée dans un réseau cellulaire ; cependant les concepts et technologies sont facilement transposables à d'autres applications telles que les radars ou les communications satellitaires. Les systèmes étudiés combinent un réseau unidimensionnel de longues fentes rayonnantes (CTS) alimentées en parallèles avec un formateur de faisceau quasi-optique (système pillbox). Les fentes rayonnantes consistent en guides à plans parallèles (GPP) tronqués. Elles sont alimentées en parallèle par un réseau de division de puissance exclusivement basé sur des GPP. Le système pillbox est constitué de deux GPP connectés par un coupleur et un réflecteur parabolique intégré, l'illumination de ce dernier par une source focale génère une onde plane. L'omniprésence de GPP au sein de l'antenne garantit une large bande de fonctionnement, et l'architecture employée permet une meilleure intégration que les antennes quasi-optiques. Ces antennes offrent donc un compromis entre un gain élevé, une large bande de fonctionnement et un profile réduit qui ne peut pas être atteint avec les autres structures présentes dans la littérature. Malheureusement ces antennes comportent également des désavantages. D'un point de vue technologique, leur fabrication est complexe et coûteuse. C'est pourquoi dans ces travaux de thèse un intérêt particulier est porté sur l'utilisation de techniques nouvelles permettant la fabrication de prototypes menant à des résultats expérimentaux. Du point de vue des performances en rayonnement, les antennes CTS/pillbox actuelles ne permettent pas de reconfigurer le rayonnement dans le plan E et le niveau de recouvrement dans le plan H est trop faible pour pouvoir être facilement exploité. Dans cette thèse, des solutions innovantes sont proposées afin de remédier à ce manque de versatilité. Enfin jusqu'à présent, le niveau des lobes secondaires dans le plan E de l'ensemble des antennes CTS alimentées en parallèle est d'environ -13,5dB. Une structure nouvelle est introduite afin de permettre une réduction de ces lobes secondaires à un niveau très faible. / The evolution of numerical technologies allowed the daily use of connected object for a large part of the world’s population. To fulfill the ever-growing demand for wireless communication, new technologies have to be developed in order to obtain higher data-rate with smaller and cheaper devices. The antenna plays a major role in communication systems and their performances are to be improved to obtain more efficient telecommunications. Indeed the rise of data-rate involves an improvement of the antenna gain and bandwidth, but the integration of directive antennas is always challenging. The actual trend is the shift to higher frequency bands, in the millimeter-wave range, this allows a size reduction together with the use of broader bandwidth; however the fabrication becomes a real challenge. The research work realized in this thesis concern the design, fabrication and experimental characterization of antennas for backhaul links: the E-band (71-86GHz) communication between two fixed antennas used in cellular network; nonetheless the solutions developed can easily be applied to other applications such as radar or satellite communications.The studied systems combine a one-dimensional array of long radiating slots (CTS) fed in parallel with a quasi-optical beam forming network (pillbox system). The radiating slots are made of truncated parallel plate waveguides (PPW) and are fed in parallel by a power-divider network realized in PPW technology. The pillbox system consists of two stacked PPWs connected by a multi-slot coupler and an integrated parabolic reflector, the latter converts the cylindrical wave emitted by a focal feed into a planar wave. The omnipresence of PPWs throughout the antenna system insures a broad band of operation, and the architecture shows a lower profile than quasi-optical antennas. This antenna presents an unequaled tradeoff between a high gain, a wide bandwidth and a low-profile. Unfortunately they also have drawbacks. From a technological point of view, their fabrication is complicated and expensive. This is why in this thesis a particular attention is given to the use of new techniques allowing the fabrication of prototypes leading to experimental validation of the results. From the radiation performance point of view, CTS/pillbox antennas do not show any reconfigurability solution in the E-plane and the overlap level obtained in H-plane with already existing antennas is too low to be usable. In this thesis, innovative solutions are investigated to find solution to this lake of versatility. Finally the sidelobe level (SLL) in E-plane of the totality of parallel-fed CTS antennas described in the open-literature is about -13.5dB. A new architecture introduced in this thesis allows a reduction of this SLL down to a negligible level.