L’utilisation des composants passifs a connu une importante croissance ces dernières décennies notamment dans le domaine de la téléphonie mobile, de l’électronique embarquée. Les travaux présentés dans cette thèse s’inscrivent dans un cadre de projet entre les laboratoires LT2C de l’UJM et Ampère de l’INSA de LYON. L’objectif visé par cette thèse est la modélisation des micro-transformateurs de signaux utilisés pour isoler les parties puissance (Driver IC) et commande (JFET ou MOSFET). Les points abordés dans cette thèse sont le choix des structures de transformateurs qui répondent aux exigences du projet, le développement d’un modèle de transformateur qui prend en compte notamment les pertes et l’évolution de la perméabilité du matériau magnétique et les différents couplages capacitifs. Des simulations à l’aide de HFSS ont été réalisées afin de réaliser le design des structures retenues et valider le modèle développé. Des étapes de fabrications compatibles avec celle de la microélectronique ont été utilisées pour fabriquer des prototypes à une couche et à deux couches de matériau magnétique avec différentes configurations. Une caractérisation haute fréquence (2MHz-200MHz) à l’aide de l’analyseur vectoriel de réseaux a été réalisée et enfin une étude comparative entre les résultats de simulation et les résultats de mesure fait l’objet d’une présentation / The use of passive components has known a significant increasing in the recent decades particularly in the area of mobile telephony, portable or embarked systems. The work presented in this thesis is a part of a project between the two laboratories: LT2C of UJM and AMPERE of INSA of Lyon. The purpose of this thesis is to find a model for signal micro-transformers used to isolate the power part (Driver IC) from the control part of the project (JFET or MOSFET). The essential parts of this thesis concern the choice of transformer structures that deal with the requirements of the project, the development of a transformer model that takes into account the losses and the permeability evolution of the magnetic material versus frequency and the different capacitive couplings. Numerous simulations using HFSS were performed in order to design the chosen structures and to validate the developed transformer model. Different steps compatible with the microelectronics manufacturing have been used to manufacture prototypes with a single magnetic layer and two magnetic layers for the different configurations. High frequency characterization (2MHz-200MHz) using the vector network analyzer was performed and finally a comparative study between the results of simulation and measurements has been the subject of a presentation

[pt] O termo de ondas milimétricas refere-se à porção do espectro eletromagnético com frequências entre 30 e 300 GHz, correspondente a comprimentos de onda de 10 até 1 mm, respectivamente. As características das ondas milimétricas diferem das micro-ondas e das infravermelhas, e são estas diferenças que fazem com que um sistema de ondas milimétricas seja o candidato ideal para algumas aplicações. Nos anos passados, a falta e o alto custo de fontes, dispositivos, componentes e instrumentação adequada, para esta faixa de frequências, levaram a um progresso muito devagar nesta área, no entanto, as limitações dos sistemas infravermelhos e ópticos e a superlotação da região do micro-ondas do espectro ocasionaram um maior interesse em frequências milimétricas nos últimos anos. A quinta geração dos sistemas móveis deve estar pronta nos próximos anos, e muitas pesquisas estão se desenvolvendo nas faixas de 28 GHz, 38 GHz e 60 GHz. A faixa de 60 GHz, na qual as ondas têm uma maior atenuação comparada com as outras duas, oferece um maior espectro eletromagnético. Nesta faixa de frequência, as ondas se refletem muito e pode se aproveitar estas reflexões para uma melhor recepção sendo, por tanto, uma ótima opção para comunicação móvel de curta distância com altas taxas de transferência de dados. Para poder aproveitar a maior quantidade de multipercursos, a antena receptora deve ter uma largura de feixe grande. Assim, neste trabalho, duas antenas foram projetadas, construídas e, de alguma forma, testadas para uma frequência de 60 GHz, onde as larguras de feixe simuladas obtidas foram de 112 graus e 115 graus. / [en] The millimeter wave term refers to that portion of the electromagnetic spectrum with frequencies between 30 and 300 GHz corresponding to wavelengths of 1 to 10 mm. The characteristics of the millimeter wave differ from microwave and infrared, and these differences make a millimeter wave system, an ideal candidate for some applications. In the past the lack and the high cost of supplies, devices, components and instrumentation suitable for this frequency band caused very rambling progress in this area. However, the limitations of infrared optical systems and overcrowding of the microwave spectrum region led to a greater interest in the millimeter frequency in recent years and it is expected an increase in this interest. The fifth generation of mobile systems should be ready in the coming years, and many studies are developing in the 28 GHz, 38GHz and 60GHz bands. In the 60 GHz band, waves has a higher attenuation compared to the other two, but also offers greater electromagnetic spectrum, in this band, waves has a lot of reflection, then, scattering can be taken for better reception. So, this band is a great choice for short distance mobile communication with high data rates. To get the greatest amount of multipath, the receiving antenna must have a wide beam width. In this work, two antennas were designed, built and somewhat tested for a frequency of 60 GHz for mobile environment, where the beam widths obtained are 112 degrees and 115 degrees.

Les circulateurs et les isolateurs à ferrite sont couramment utilisés dans l’électronique hyperfréquence en raison de leur forte résistivité électrique et de leur aimantation spontanée élevée. La conception et l’optimisation des dispositifs micro-ondes à ferrites nécessitent d’une part la connaissance de leurs propriétés dynamiques, permittivité complexe et tenseur de perméabilité, et d’autre part le contrôle de la propagation de l’onde électromagnétique (EM) qui conditionne leurs performances. Les logiciels commerciaux de simulation utilisent différents modèles théoriques pour décrire le tenseur de perméabilité en fonction de l’état d’aimantation. Cependant la plupart de ces simulateurs EM restent limités à des états particuliers d’aimantation en raison des hypothèses simplificatrices des modèles de perméabilité utilisés. Dans ce travail de thèse, nous présentons un outil prédictif pour l’étude des propriétés EM des ferrites quel que soit leur état d’aimantation et qui tient compte de l’inhomogénéité des champs internes de polarisation. Cette modélisation combine des techniques expérimentales de détermination des paramètres physiques des ferrites et un modèle théorique qui utilise ces paramètres pour décrire le comportement dynamique des ferrites quel que soit l’état d’aimantation. Dans la première partie de la thèse nous présentons une méthode large bande en ligne coaxiale pour la mesure du coefficient d’amortissement. Les paramètres S théoriques sont calculés à partir d’une analyse EM (problème direct) de la cellule de mesure. Pour le problème inverse, une optimisation numérique a été développée pour calculer le coefficient d’amortissement (α) par comparaison des paramètres S calculés avec ceux mesurés. Dans la seconde partie de la thèse, nous présentons un outil théorique de modélisation EM qui combine une analyse magnétostatique, un modèle du tenseur de perméabilité généralisé (GPT) et le simulateur Ansys HFSSTM. La majorité des paramètres d’entrée comme l’aimantation à saturation ou le champ d’anisotropie peuvent être mesurés à l’aide de techniques standards de caractérisation statique. Seul le paramètre dynamique, le coefficient d’amortissement, est déterminé à l’aide de la technique en ligne coaxiale proposée dans la première partie de la thèse. L’outil théorique développé est ensuite validé par la modélisation et la réalisation d’un circulateur micro-ruban à jonction Y. Grâce à la prise en compte de l’inhomogénéité des champs internes de polarisation, l’outil théorique proposé permet de mieux prédire le comportement dynamique des dispositifs à ferrites et cela pour tout état d’aimantation. / Ferrites are widely used in microwave electronics, particularly for circulators and insulators, because of their high electrical resistivity and high spontaneous magnetization. Design and optimization of microwave devices using ferrites requires realistic knowledge of its dynamic response, namely complex permittivity and permeability tensor and, on the other hand, control of wave propagation that condition their performance. Commercial simulation software use different theoretical models to describe the permeability tensor according to the state of magnetization. However, most of the electromagnetic (EM) simulators remain limited to certain states of magnetization, due to the simplified assumptions on which their permeability models are based upon.In this thesis work, we presented a predictive electromagnetic tool to study the EM properties of ferrites, whatever their magnetization state is, and takes into account the inhomogeneity of the internal polarization fields. This theoretical modeling approach combines experimental techniques to find the physical parameters of the ferrites, and a theoretical model which will use these parameters to describe the dynamic behavior of ferrites at any magnetization state.In the first part of the thesis, we presented a broadband coaxial line method for damping factor measurement. Theoretical S parameters are calculated using the EM analysis (direct problem) of the measurement cell. In the inverse problem, a numerical optimization procedure is developed to compute the damping factor (α) by matching theoretical S parameters with measured S parameters.During the second part of the thesis, we developed a theoretical EM modeling tool which combines a magneto-static solver, generalized permeability tensor model and commercial simulation software Ansys HFSSTM. Most of the input parameters like saturation magnetization, anisotropy field, etc. can be measured using standard characterization methods, except the damping factor used to represent the dynamic losses. Static input parameters of this theoretical tool are determined using standard material characterization methods.Dynamic input parameter, damping factor is calculated using the coaxial line technique proposed in the first part of this thesis. Theoretical EM tool is validated by modeling, and realizing a microstrip Y-junction circulator. By taking into account the inhomogeneity of the internal polarizing fields, proposed theoretical tool can predict the dynamic behavior of ferrite devices more accurately, at all magnetization states.

Stroke is amongthe leading causes of death worldwide and requires immediate care to prevent death or permanent disability. Unfortunately, the current stateof stroke diagnosis is limited to fixed neuroimaging facilities that do not allow rapid stroke diagnosis. Hence, a portable stroke-diagnosis device could assist in the pre-hospital triage of patients. Moreover, such a portable device could also be useful for bedside stroke monitoring of patients in the Neuro Intensive Care Unit (Neuro-ICU) to avoid unnecessary neuroimaging. Recent animal studies and numerical simulations have supported the idea of implementing Electrical Bioimpedance (EBI) in a portable device, allowing non-invasive assessment as a useful tool for the pre-hospital triage of stroke and Traumatic Brain Injury (TBI) patients. Unfortunately, these studies have not reported any results from human subjects in the acute phase of the stroke. The numerical simulations are also based on simple models that sometimes lack necessary details. Finite Element Method (FEM) simulations on a realistic numerical head model as well as experimental Bioimpedance Spectroscopy (BIS) measurements from human subjectsin the acute, subacute and chronic phasesof stroke were used to answer the following research questions: (i) Does stroke modify the electrical properties of brain tissue in a way that is detectable via EBI? (ii) Would it be possible to detect stroke via EBI as early as in the acute and sub-acute phase?(iii) Is EBI sensitive enough to monitor changes caused by stroke pathogenesis? Using FEM to simulate electrical current injection on the head and study the resulting distribution of electrical potential on the scalp, it was shown that Intra-Cranial Hemorrhage (ICH) affects the quasi-symmetric scalp potential distribution,creating larger left-right potential asymmetry when compared to the healthy head model. Proof-of-concept FEM simulations were also tested in a small cohort of 6ICH patients and 10 healthy controls, showing that the left-right potential difference in the patients is significantly (p&lt;0.05) larger than in the controls. Using bioimpedance measurements in the acute,  subacute and chronic phasesof stroke and examining simple features, it was also shown that the head EBI measurements of patients suffering stroke are different from controls, enabling the discrimination of healthy controls and stroke patients at any stage of the stroke. The absolute change in test-retest resistance measurements of the control group (~5.33%) was also found to be significantly (p&lt;0.05) smaller than the EBI measurements of patients obtained 24 hours and 72 hours after stroke onset (20.44%). These results suggested that scalp EBI is sensitive to stroke pathogenesis changesand thususeful for bedside monitoring in the Neuro-ICU. These results suggested that EBI is a potentially useful tool for stroke diagnosis and monitoring. Finally, the initial observations based on a small number of patients, addressing the proposed future work of this thesis, suggested that the average head resistance amplitude of hemorrhagic stroke patients is smaller than in healthy controls, while ischemic stroke patients show a larger resistance amplitude than the controls. Scalp potential asymmetry analysis of healthy, hemorrhagic and ischemic stroke subjects also suggests that these three groups can be separated. However, these results are based on a small number of patients and need to be validated using a larger cohort. Initial observations also showed that the resistance of the EBI measurements of controls is robust between test and retest measurements, showing no significant difference (less than 2% and p&gt;0.05). Subject position during EBI recording (supine or sitting) did not seem to affect the resistance of the EBI measurements (p&gt;0.05). However, age, sex and head size showed significant effects on the resistance measurements. These initial observations are encouraging for further research on EBI for cerebral monitoring and stroke diagnosis. However, at this stage, considering the uncertainties in stroke type differentiation, EBI cannot replace CT but has the potential to be used as a consultation tool. / <p>QC 20151109</p>

Electromagnetic equations pertaining to electrically small dipole antennas and electrically small monopole antennas with small circular ground planes are reviewed. Two electrically small antenna designs are analyzed numerically and the results are compared. The first is a frequency agile version of the two-dimensional (2D) planar Egyptian axe dipole (EAD) antenna. The second is its three-dimensional (3D) counterpart. The frequency agile performance characteristics of both the 2D and 3D EAD designs are studied and compared. The potential for non-Foster augmentation to achieve large instantaneous fractional impedance bandwidths is detailed for each antenna. In addition, details are given on how to run frequency agile simulations in both ANSYS HFSS and Agilent's ADS. Details are also provided on how to generate an antenna's non-Foster |S₁₁| and radiation efficiency curves using HFSS, and how to generate an antenna's non-Foster |S₁₁| curve using ADS.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-03-20T19:50:21Z No. of bitstreams: 1 RafaelCelestinoDosSantos_DISSERT.pdf: 2928154 bytes, checksum: ed85070c1f646df9265898c17421fbdd (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-03-22T19:46:13Z (GMT) No. of bitstreams: 1 RafaelCelestinoDosSantos_DISSERT.pdf: 2928154 bytes, checksum: ed85070c1f646df9265898c17421fbdd (MD5) / Made available in DSpace on 2017-03-22T19:46:13Z (GMT). No. of bitstreams: 1 RafaelCelestinoDosSantos_DISSERT.pdf: 2928154 bytes, checksum: ed85070c1f646df9265898c17421fbdd (MD5) Previous issue date: 2016-12-16 / Este trabalho tem por objetivo apresentar a influ?ncia de uma metasuperf?cie, um tipo especial dos metamateriais, no desempenho das antenas de microfitas. As metasuperf?cies s?o materiais artificiais que n?o s?o encontrados em sua forma convencional na natureza e apresentam caracter?sticas eletromagn?ticas n?o convencionais, como o ?ndice de refra??o e os coeficientes de permissividade el?trica e permeabilidade magn?tica negativos o que provocam efeitos eletromagn?ticos atrativos para diversas aplica??es, como por exemplo: melhorar a performance de uma antena de microfita como ser? mostrado nesse trabalho. Iniciaremos o trabalho mostrando um breve hist?rico, defini??es e propriedades eletromagn?ticas das antenas, antenas de microfita, metamateriais e das metasuperf?cies. Em seguida, iremos projetar e confeccionar uma antena de microfita com e sem a utiliza??o de uma metasuperf?cie onde simularemos atrav?s do software HFSS Ansoft Designer e testaremos em laborat?rio atrav?s do equipamento E5071C ENA Network Analyzer. Por fim, realizaremos uma an?lise comparativa, mostrando o quanto a metasuperf?cie melhora a performance de uma antena de microfita atrav?s de uma an?lise dos diversos par?metros da antena, como: perda de retorno, ganho de pot?ncia, diretividade e imped?ncia de entrada. / This paper aims to present the influence of a metasurface, a special type of metamaterials, in the performace of microstrip antennas. The metasurface are artificial materials that are not found in a conventional manner in nature and do not have conventional electromagnetic characteristics such as refractive index and coefficient of permittivity and negative magnetic permeability which causes attractive electromagnetic effects for various applications, such as: improving the performance of a microstrip antenna as will be shown in this work. We started the work showing a brief history, definitions and electromagnetic properties of the antennas, microstrip antennas, metamaterials and metasuperf?cies. Next, we will design and manufacture a microstrip antenna with and without the use of a metasurface where we will simulate through HFSS Ansoft Designer software and test in the laboratory with the E5071C ENA Network Analyzer. Finally, we will perform a comparative analysis, showing how the metasurface improves the performance of a microstrip antenna by analysis of the various parameters antenna, such as: return loss, power gain, directivity and input impedance.

nÃo hà / Com o rÃpido crescimento das indÃstrias de telecomunicaÃÃes criou-se uma forte necessidade por materiais cerÃmicos para aplicaÃÃes em micro-ondas. Devendo estes materiais apresentar alta permissividade dielÃtrica (&#949;r), elevado fator de qualidade (Q), boa estabilidade tÃrmica (&#964;f Â10 ppm/ÂC) e baixo custo. Com a invenÃÃo de telefones celulares portÃteis, o campo da comunicaÃÃo sem fio passou por um crescimento inovador nas Ãltimas dÃcadas. O sucesso da terceira geraÃÃo (3G) dos serviÃos de comunicaÃÃo de telefonia celular, motiva o desenvolvimento de banda larga de quarta geraÃÃo (4G) de telefones celulares e outros produtos e serviÃos sem fio, como por exemplo, o Bluetooth. Este trabalho consiste no desenvolvimento e caracterizaÃÃo da cerÃmica de titanato de bÃrio-bismuto (BaBi4Ti4O15) com adiÃÃo de Ãxido de niÃbio (Nb2O5) ou Ãxido de zinco (ZnO), visando a diminuiÃÃo da temperatura de sinterizaÃÃo e possivelmente melhorar a densificaÃÃo, e posteriormente, verificar as modificaÃÃes ocorridas nas propriedades do material, como por exemplo, o coeficiente de temperatura da frequÃncia ressonante (&#964;f). As sÃries cerÃmicas foram produzidas usando a reaÃÃo no estado sÃlido, com o uso de moagem mecÃnica de alta energia e tratamento tÃrmico. A caracterizaÃÃo estrutural foi realizada com base na Microscopia EletrÃnica de Varredura (MEV) e Picnometria. As densidades relativas das amostras adicionadas com (ZnO) a de maior concentraÃÃo teve valor de 77% enquanto que o BBT puro o valor foi de 56%. As densidades relativas das amostras adicionadas com (Nb2O5) a de maior concentraÃÃo teve valor de 61% em relaÃÃo ao BBT puro. Foram realizados experimentos para avaliaÃÃo do comportamento elÃtrico e dielÃtrico das amostras, na faixa de Micro-ondas e RadiofrequÃncia (temperatura ambiente e com variaÃÃo de temperatura). Por fim, o material foi testado como uma DRA, e posteriormente os resultados obtidos foram simulados atravÃs do programa HFSS. As caracterÃsticas da DRA da cerÃmica pura sÃo 1,12dBi de ganho e 32,51% de eficiÃncia. A DRA que foi adicionada com 2% de (ZnO) apresentou ganho de 1,16dBi com 33,96% de eficiÃncia, enquanto a que foi adicionada com 5% de (Nb2O5) apresentou 1,41dBi de ganho com 42,21% de eficiÃncia. / With the rapid growth of the telecommunications industry created a strong need for ceramic materials for applications in microwave. These materials should exhibit high dielectric permittivity (&#949;r), high quality factor (Q), good thermal stability (&#964;f Â10 ppm/ÂC) and low cost. With the invention of mobile phones, the field of wireless communication has undergone a revolutionary growth in recent decades. The success of the third generation (3G) services in mobile communication, motivates the development of broadband fourth generation (4G) of mobile phones and other wireless products and services, such as Bluetooth. Nowadays it is well known the use of tablets, which are increasingly gaining market and encouraging the development of new technologies to improve the flow of information. This work involves the development and characterization of the barium bismuth titanate ceramic, (BaBi4Ti4O15) with addition of niobium oxide (Nb2O5) or zinc oxide (ZnO) in order to decrease the sintering temperature and possibly improve the densification and subsequently check the modifications on material properties, such as the temperature coefficient of resonant frequency (&#964;f). The series ceramics were produced using the solid state reaction with the use of high energy mechanical milling and heat treatment. The structural characterization was performed based on Scanning Electron Microscopy (SEM) and Measurement by Pycnometer. The relative densities of the samples with added (ZnO) had the highest concentration value of 77% pure BBT while the value was 56%. The relative densities of the samples spiked with (Nb2O5) had the highest concentration value of 61% compared to pure BBT. Experiments were conducted to evaluate the electrical and dielectric behavior of the samples in the range of Microwave and Radio Frequency (temperature and temperature variation). Finally, the material was tested as a DRA, and then the results were simulated using the HFSS program. The characteristics of the pure ceramic DRA are 1,12dBi gain and 32,51% efficiency. The DRA added with 2% (ZnO ) showed 1.16dBi gain with 33,96% efficiency , while the one that was added with 5% (Nb2O5) showed gain of 1.41dBi with 42,21% efficiency.

This thesis evaluates two array antenna elements for large phased array antennas. The two antenna concepts are a surface mounted notch element and a PIFA (Planar Inverted F Antenna). The antennas have been simulated at S-band in Ansys HFSS as a unit cell in an infinite array environment. Thereafter, a finite 7 x 7 element array of the two concepts was simulated. A corresponding 49 element array, using the notch element, was built and measured upon. Embedded element patterns and S-matrix parameters have been measured. From this result, full array antenna patterns as well as active reflection coefficients have been calculated. The measurements show very good performance for large scan angles and a wide frequency range.

The aim of this thesis is to identify coupling mechanisms for three line microstrip, stripline and microstrip with dielectric overlay structures as either inductive or capacitive, quantify through simulation and measurement the amount of crosstalk to be expected in terms of scattering parameters. A new method of crosstalk suppression is implemented into each three line structure by placing uniformly spaced short circuits down the length of the center transmission line. All structures were simulated over various physical and electrical parameters. Select microstrip structures, shielded and unshielded, were fabricated and measured to validate the effectiveness of the shielding technique. Shielding effectiveness was calculated from the measurements, and their results showed that the isolation between lines was increased by up to 20dB.

Creating accurate software based models of phased array feeds (PAFs) is one of many steps to successfully integrating PAFs with current and future radio telescopes, which is a goal of many groups around the globe. This thesis characterizes the latest models of a 19 element hexagonal PAF of dipoles used by the BYU radio astronomy research group and presents comparisons of these models with experimental data obtained using a prototype array. Experiments were performed at the NRAO site in Green Bank, West Virginia, and utilized the outdoor antenna test range and 20 meter radio telescope. Accurate modeling of the PAF requires modeling the signal and noise characteristics of the array, which is a computationally large problem. It also requires accurate modeling of the noise contribution of the receivers connected to the coupled array, which is something that has only recently been understood. The modeled and measured element receive patterns, array impedance matrix, signal and noise correlation matrices, and efficiencies and sensitivities of the PAF are compared and promising levels of agreement are shown. Modeled sensitivity is 30 to 46% larger than measured.