Dissertations / Theses on the topic 'Transmission line theory'

This thesis presents how to estimate the length of a power cable using the MaximumLikelihood Estimate (MLE) technique by using Matlab. The model of the power cableis evaluated in the time domain with additive white Gaussian noise. The statistics havebeen used to evaluate the performance of the estimator, by repeating the experiment fora large number of samples where the random additive noise is generated for each sample.The estimated sample variance is compared to the theoretical Cramer Raw lower Bound(CRLB) for unbiased estimators. At the end of thesis, numerical results are presentedthat show when the resulting sample variance is close to the CRLB, and hence that theperformance of the estimator will be more accurate.

Cette thèse présente, dans un premier temps, une nouvelle approche pour traiter les lignes de transmission, appelée la Théorie des Lignes de Transmission Améliorée et Modifiée (TLTAM). Cette extension du formalisme classique de la théorie des lignes de transmission est directement dérivée des équations de Maxwell et ne se limite pas à la seule prise en compte du mode transverse électromagnétique (TEM). Tout en conservant la simplicité du formalisme classique, cette extension aboutit à la définition de paramètres linéiques évolués et associés au mode antenne de la ligne de transmission. Cette solution présente l’avantage d’être compatible avec les noyaux de calcul existants, tout en palliant certaines limitations de la théorie des lignes de transmission (TLT) classique. LA TLTAM est tout d’abord définie pour le cas élémentaire d’une ligne de transmission à conducteur unique. Elle est ensuite généralisée au cas d’un nombre quelconque de conducteurs. Les matrices de paramètres linéiques correspondants sont alors définies. Les capacités de cette nouvelle théorie sont démontrées et validées au moyen de confrontations avec la solution directe des équations de Maxwell et de résultats de mesure. Dans un deuxième temps, le traitement d’une ligne de transmission multiconducteur située à distance d’un plan de référence conducteur est effectué au moyen d’une nouvelle approche désignée sous le nom de Théorie des Lignes de Transmission à Double Référence Intégrée (TLTDRI). Cette approche permet de simplifier l’évaluation des paramètres linéiques du faisceau en scindant le problème initial en deux sous-ensembles de lignes de transmission couplées. Le premier sous-ensemble est composé d'un fil conducteur du faisceau choisi arbitrairement et le plan de référence et constitue le sous-ensemble externe. Le deuxième sousensemble est composé uniquement des fils conducteurs du faisceau, en l’absence du plan de référence et constitue un sous-ensemble interne dont la référence locale est le fil choisi précédemment. On montre alors que seul le sous-ensemble externe nécessite le calcul de paramètres linéiques évolués associés à TLTAM. Le calcul des paramètres linéiques dans le système à référence unique constituée par le plan de référence, est reconstitué à partir de formules de passage permettant leur expression à partir des paramètres linéiques des deux sousensembles. Cette approche est validée et ses résultats sont en très bon accord avec ceux fournis par un calcul numérique direct des équations de Maxwell ainsi que ceux de la TLTAM. Elle permet une simplification très significative du traitement de l’interaction entre le faisceau de câble et la structure conductrice de référence
This thesis presents, in a first step, a new approach to deal with transmission lines called the Modified Enhanced Transmission Line Theory (METLT). This extension of the classical formalism of the transmission line theory (TLT) is directly derived from Maxwell's equations without the restriction to the transverse electromagnetic (TEM) mode. This extension leads to the definition of enhanced per-unit-length (p.u.l.) parameters taking into account the antenna mode of the transmission line, while it keeps the simplicity of the classical formalism. This solution presents the advantage of being compatible with the existing TLT solvers while overcoming some limitations of the classical TLT. The METLT is firstly developed for the simple case of a single conductor transmission line. It is then generalized to the case of any number of conductors. The corresponding matrices of the p.u.l. parameters are then calculated. The capabilities of this new theory are demonstrated and validated by the means of comparisons with results obtained through a rigorous resolution of Maxwell's equations and measurements results. In a second step, a multi-conductor transmission line sufficiently far from the reference ground plane is assessed through a new approach called: Embedded Double Reference Transmission Line Theory (EDRTLT). This approach allows the simplification of the calculation of the harness p.u.l. parameters by splitting the first set of wires above a ground plane into two subsets of coupled transmission lines. The first subset consists in a conducting wire chosen arbitrarily and the reference ground plane and forms the external subset. The second subset consists only in the conducting wires of the harness, in the absence of the ground plane, and forms an internal subset which local reference is the wire chosen previously. We show that only the external subset requires the calculation of the enhanced p.u.l. parameters with the METLT. The calculation of the harness p.u.l. parameters in the system with a single reference, which is the ground plane only, is made through transformation formulae that allow their extraction from the p.u.l. parameters of the two subsets. This approach is validated and its results are in a very good agreement with those obtained by a rigorous resolution of Maxwell's equations and those of the METLT. It allows a great simplification to assess the interaction between the harness and the reference conducting structure

The multi-conductor lossy transmission-line model and finite element simulation tool are used to analyze the high-frequency attenuator and the DM transmission-line EMI filter. The insertion gain, transfer gain, current distribution, and input impedance of the filter under a nominal design are discussed. In order to apply the transmission-line EMI filter to power electronics systems, the performance of the filter under different dimensions, material properties, and source and load impedances must be known. The influences of twelve parameters of the DM transmission-line EMI filter on the cut-off frequency, the roll-off slope, and other characteristics of the insertion gain and transfer gain curves are investigated. The most influential parameters are identified. The current sharing between the copper and nickel conductors under different parameters are investigated. The performance of the transmission-line EMI filter under different source and load impedances is also explored. The measurement setups of the DM transmission-line EMI filter using a network analyzer have been discussed. The network analyzer has a common-ground problem that influences the measured results of the high-frequency attenuator. However, the common-ground problem has a negligible influence on the measured results of the DM transmission-line EMI filter. The connectors and copper strips between the connectors and the filter introduce parasitic inductance to the measurement setup. Both simulated and measured results show that transfer gain curve is very sensitive to the parasitic inductance. However, the insertion gain curve is not sensitive to the parasitic inductance. There are two major methods to reduce the parasitic inductance of the measurement setup: using small connectors and applying a four-terminal measurement setup. The transfer gain curves of three measurement setups are compared: the two-terminal measurement setup with BNC connectors, the two-terminal measurement setup with Sub Miniature version B (SMB) connectors, and the four-terminal measurement setup with SMB connectors. The four-terminal measurement setup with SMB connectors is the most accurate one and is applied for all the transfer gain measurements in this dissertation. This dissertation also focuses on exploring ways to improve the performance of the DM transmission-line EMI filter. Several improved structures of the DM transmission-line EMI filter are investigated. The filter structure without insulation layer can greatly reduce the thickness of the filter without changing its performance. The meander structure can increase the total length of the filter without taking up too much space and results in the cut-off frequency being shifted lower and achieving more attenuation. A prototype of the two-dielectric-layer filter structure is built and measured. The measurement result confirms that a multi-dielectric-layer structure is an effective way to achieve a lower cut-off frequency and more attenuation. This dissertation proposes a broadband DM EMI filter combining the advantages of the discrete reflective LC EMI filter and the transmission-line EMI filter. Two DM absorptive transmission-line EMI filters take the place of the two DM capacitors in the discrete reflective LC EMI filter. The measured insertion gain of the prototype has a large roll-off slope at low frequencies and large attenuation at high frequencies. The dependence of the broadband DM EMI filter on source and load impedances is also investigated. Larger load (source) impedance gives more attenuation no matter it is resistive, inductive or capacitive. The broadband DM EMI filter always has more high-frequency attenuation than the discrete reflective LC EMI filter under different load (source) impedances.
Ph. D.

At present, induction motors are controlled via the so-called variable-frequency drives (VFD) that allow to control the speed for the motors. The purpose of this PhD thesis is to improve electromagnetic modeling techniques for the study of conducted electromagnetic emissions in variable-frequency drives, with the aim of enhancing their reliability in energy production plants. Pulse-width-modulated voltage converters are used to feed an AC motor, and they are considered to be the primary reason for high-frequency effects in both the motor and the supply grid. In particular, high-frequency currents, known as common mode currents, flow between all energized components and the ground and travel via low-resistance and low-inductance interconnects such as the power cable between the inverter and the motor.Electrically long power cables are commonly used in VFD installations, and require particular attention. Accurate models can be obtained using the theory of multiconductor transmission lines. In the case of nonlinear terminations, such as an inverter, only time-domain analysis is possible. In recent years, several techniques have been proposed. Some of these techniques include the lumped-element equivalent circuit method, the method of characteristics (MoC) and its generalizations, and the Pad´e approach. In this context, a modeling technique based on Green’s functions has been proposed. The input/output impedance matrix is expressed as a rational series, whose poles and their residues are identified by solving algebraic equations. The primary disadvantage of this method lies in the large number of poles that is typically necessary to model the dynamics of the system, especially when electrically long interconnectsare considered. To overcome this limitation, we have proposed the Delay-Rational Green’s-Function-based Method, abbreviated as DeRaG. In this method, the line delay is extracted and, by virtue of suitable mathematical manipulation of the rational series, is incorporated through hyperbolic functions. The delay extraction enables the use of a reduced number of poles and improves the accuracy of the model in general, avoiding any ringing effects in the time-domain response. The primary advantage of the proposed method compared with other well-known techniques lies in the delayed state-space representation. The obtained model can be computed regardless of the terminations and/or sources, and the terminal conditions can be immediately and essentially incorporated.The next step will be to simulate the entire inverter-cable-motor system. The partial element equivalent circuit (PEEC) technique will be used to model the interconnects as well as the discontinuities in the power cable that can be caused, for example, by switch disconnectors. The theoretical results will be verified against experimental measurements. The final objective is to provide new techniques for modeling the electrodynamics of variable-frequency drives to allow their complete EMC assessment as early as the design stage and to enable the planning of corrective actions in advance.

Godkänd; 2016; 20160318 (mardel); Nedanstående person kommer att hålla licentiatseminarium för avläggande av teknologie licentiatexamen. Namn: Maria De Lauretis Ämne: Industriell Elektronik/Industrial Electronics Uppsats: Transmission Line Theory for Cable Modeling: A delay-rational model based on Green’s functions Examinator: Professor Jonas Ekman, Institutionen för system- och rymdteknik, Avdelning: EISLAB, Luleå tekniska universitet. Diskutant: Professor Sven Nordebo, Institutionen för fysik och elektroteknik, Linnéuniversitetet, Växjö. Tid: Tisdag 3 maj, 2016 kl 10.30 Plats: A1547, Luleå tekniska universitet

Frekvensomriktares funktion i beredskapskritiska system

The cascade algorithm that is used for extended surface analysis depends on a new parameterization called the thermal transmission matrix to represent a single fin. This thermal transmission matrix, which is intended to replace the more familiar fin efficiency as a design and analysis parameterization, is a linear transformation that maps conditions of heat flow and temperature at the fin tip to heat flow and temperature conditions at the fin base. The cascade algorithm was derived by resorting to an analogy between a fin and the electrical transmission line. The cascade algorithm permits a fin to be subdivided into many subfins each having a thermal transmission matrix and then the individual transmission matrices for each of the subfins can be used, via a simple matrix product to form an overall equivalent thermal transmission matrix for the entire fin. This thesis develops a thermal transmission matrix for the radiating rectangular, trapezoidal, and triangular fins both for the free space and non-free space environments. Test cases have been run and their solutions exactly match those contained in the literature. The thesis concludes with optimization studies for Thermal Transmission Matrix, Cascade Algorithm, Extended Surface, Cooling Fin, Radiative Fin, Longitudinal Fin, Rectangular Fin, Trapezoidal Fin, Triangular Fin, Optimum

In this thesis, having in mind applications to the fault-detection/diagnosis of electrical networks, we consider some inverse scattering problems for the Zakharov-Shabat equations and time-independent Schrödinger operators over star-shaped graphs. The first chapter is devoted to describe reflectometry methods applied to electrical networks as an inverse scattering problems on the star-shaped network. Reflectometry methods are presented and modeled by the telegrapher's equations. Reflectometry experiments can be written as inverse scattering problems for Schrödinger operator in the lossless case and for Zakharov-Shabat system for the lossy transmission network. In chapter 2 we introduce some elements of the inverse scattering theory for 1 d Schrödinger equations and the Zakharov-Shabat system. We recall the basic results for these two systems and we present the state of art of scattering theory on network. The third chapter deals with some inverse scattering for the Schrödinger operators. We prove the identifiability of the geometry of the star-shaped graph: the number of the edges and their lengths. Next, we study the potential identification problem by inverse scattering. In the last chapter we focus on the inverse scattering problems for lossy transmission star-shaped network. We prove the identifiability of some geometric informations by inverse scattering and we present a result toward the identification of the heterogeneities, showing the identifiability of the loss line factor.

This thesis aims at detecting and classifying the power system transmission line faults. To deal with the problem of an extremely large data set with different fault situations, a three step optimized Neural Network approach has been proposed. The approach utilizes Discrete Wavelet Transform for detection and two different types of self-organized, unsupervised Adaptive Resonance Theory Neural Networks for classification. The fault scenarios are simulated using Alternate Transients Program and the performance of this highly improved scheme is compared with the existing techniques. The simulation results prove that the proposed technique handles large data more efficiently and time of operation is considerably less when compared to the existing methods.

Thesis (Ph.D)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009.
Committee Chair: Divan, Deepakraj M.; Committee Member: Begovic, Miroslav M.; Committee Member: Brown, Marilyn; Committee Member: Harley, Ronald G.; Committee Member: Wolf, Wayne H. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Orientador: Sérgio Kurokawa
Resumo: Nos sistemas de potência, o conhecimento dos parâmetros das linhas de transmissão possibilita o ajuste preciso dos sistemas de proteção, facilita a aplicação de ferramentas e técnicas de análise do sistema elétrico, permite a correta localização de faltas, assim como o monitoramento de indicadores comuns de faltas, como a temperatura e a catenária do condutor. As metodologias de estimação de parâmetros de linha de transmissão baseadas na teoria da decomposição modal são restritas a configurações de torre específicas, nas quais a matriz de transformação da linha de transmissão é conhecida. Neste trabalho apresenta-se um método para a estimação de parâmetros de linhas de transmissão genéricas em regime permanente, utilizando os fatores de correntes e tensões nos terminais da linha. Estabelece-se um sistema de equações não linear indeterminado, a partir das relações fase-modo das correntes e tensões nos terminais da linha e as matrizes de impedância e admitância da linha. Para uma linha trifásica genérica as relações fase-modo são escritas em função dos elementos da matriz transformação, os quais são desconhecidos e uma parte das incógnitas do sistema de equações. O sistema de equações é complementado com equações adicionais para ser resolvido mediante o algoritmo de Newton-Raphson e estimar os parâmetros de linha de transmissão. Foram estimados os parâmetros para uma linha de transmissão trifásica com diferente configuração de torre operando com diferentes cargas para vários co... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Accuracy in transmission lines parameters is essential in power systems since it allows precise adjustment of the protection systems, the application of tools and techniques for analysis of the electrical system, the correct identification of fault location, as well as the monitoring of fault indicators such as the temperature and the catenary of the conductor. Transmission line parameter estimation methodologies based on modal decomposition theory are restricted to specific tower configurations in which the transformation matrix of the transmission line is known. This work presents a method to estimate parameters of generic transmission lines in the steady state, using the voltage and currents phasor at the terminals of the line. A system of consistent non-linear equations is established from the phase-mode relations of these voltage and current phasors and the impedance and admittance matrices of the line. The phase-mode relations are written as a function of the elements within the transformation matrix, which are unknown and part of the variables to be estimated. The system of equations is solved using the Newton-Raphson algorithm to estimate both the transmission line parameters and the transformation matrix. The parameters were estimated for three-phase transmission lines for a particular tower configuration operating under different loads and lengths. The relative error of the estimated parameters evaluates the method’s accuracy and the influence of the line’s lumped r... (Complete abstract click electronic access below)
Doutor

Ringing represents the main cause of signal distortion and communication errors in CAN FD networks, and it is generated by the repeated reflections owing to the inherent impedance mismatch in the physical bus of a CAN. Consequently, automotive manufacturers can exploit the potential of the CAN FD protocol only if ringing is suppressed. In this thesis is demonstrated that by inserting technologically innovative plug & play modules, called RACANs, it is possible to knock down ringing on the vehicle CAN network, allowing the use of the CAN FD protocol on existing CAN architectures with a very high level of in-vehicle communication reliability and without having to make any topological changes. The RACAN technology is described in detail, and the excellent results obtained in bench tests and in in-vehicle test are shown. This innovative product will allow car makers to be ready for the market demand of the next five years, without having to redesign and invest in the development of a new architecture.

This work focuses on a search of available literature on the theory of transmission lines and verify the possibility of simulation processes on these lines using a suitable simulation program. Initially, for the introduction to the parameters and the phenomenon that characterize the line and are important for understanding the issue. These parameters are then measured and compared with traces from the simulation in program PSpice. In another part of the work, the reader is familiar with the basics of reflectometry and fault detection capabilities on transmission lines with the basic reflectometry methods TDR and FDR, as well as with other methods of OTDR, MSR, and PD-FDR. For the TDR, FDR and MSR methods were made experimental measurements with a view to determining the position of the various types of faults on the tested leadership.

Pour répondre aux exigences réglementaires de plus en plus sévères au regard des émissions de CO2, l'industrie automobile voit poindre l'émergence des chaînes de traction électrique dans des structures véhicules en matériaux composites. Dans ce manuscrit, le point de vue du constructeur automobile est considéré. En effet, pour répondre aux exigences automobiles en compatibilité électromagnétique (CEM) pour l'homologation et la protection de la santé des personnes vis-à-vis des champs électriques et magnétiques, le blindage électromagnétique est l'une des solutions de conception les plus utilisées. Afin d'évaluer les meilleurs concepts à moindre coût et réduire autant que possible les délais de prototypage, la modélisation et la simulation numérique doivent encore se développer et être déployées. Les chapitres de ce manuscrit illustrent, étape par étape, la modélisation, la simulation et la validation expérimentale du blindage d'une architecture de chaîne de traction électrique. Dans un premier temps,l'influence d'un matériau composite à savoir l'époxy renforcé en fibres de carbone est étudié sur les émissions conduites et rayonnées en présence d'un câble blindé. Dans un deuxième temps, une méthodologie de modélisation des câbles blindés et des raccords de masse est proposée dans un environnement électromagnétique où la théorie des lignes de transmission classique ne s'applique pas. Pour valider les deux précédentes parties, des bancs de mesure sont proposés et développés. Les résultats expérimentaux sont comparés à la simulation numérique. La dernière partie considère une chaîne de traction électrique simplifiée en présence de boîtiers métalliques, de câbles de puissance blindés, de raccords de blindage et de raccords de masse dans une structure multi-matériaux dans la bande de fréquences 10 kHz - 300 MHz. Les émissions conduites et rayonnées sont analysées en portant une attention particulière à la perturbation de la réception radio
To reach the increasingly stringent regulatory requirements for CO2 emissions, the automotive industry is improving the electric powertrains in car bodies with composite materials. In this thesis report, the point of view of the car manufacturer is considered. The electromagnetic shielding is one of the most important design solutions to respect the electromagnetic compatibility (EMC) requirements for the homologation and the protection of human health with respect to electrical and magnetic fields. In order to evaluate the best concepts at lower costand to minimize prototyping delays, modeling and numerical simulation still need to be developed and deployed.The chapters of this thesis report illustrate, step by step, the modeling, the simulation and the experimentalvalidation of the shielding applied to an electric powertrain. In a first step, the influence of a composite material such as the carbon fiber reinforced epoxy is studied on the conducted and the radiated emissions in presence of a shielded cable. In a second step, a methodology to model shielded cables and the grounding connectionsis proposed in an electromagnetic environment where classical transmission line theory cannot be applied. Tovalidate the two previous parts, measurement setups are proposed and developed. The experimental results arecompared with the numerical simulation. The last part considers a simplified electric powertrain with metal housings, shielded power cables, shielding connections and grounding connections in a multi-material structurein the 10 kHz - 300 MHz frequency band. The conducted and radiated emissions are analyzed with a particular attention to the disturbance of the radio reception

Le travail de recherche proposé dans ce manuscrit consiste à modéliser le rayonnement électromagnétique de conducteurs filaires. En effet l'estimation du rayonnement est un enjeu majeur et l'utilisation de modèles exacts nous semble nécessaire. On propose donc dans ce mémoire une approche analytique qui permet de quantifier les niveaux de champs électromagnétiques rayonnés par les systèmes filaires. Dans un premier temps nous proposons un modèle analytique du calcul du champ électromagnétique rayonné par un système filaire basé sur un développement approfondi des équations de Maxwell. Ce formalisme est issu de la formulation intégrale du potentiel vecteur émis par une antenne filaire dont on supposera connu la distribution de courant. Le modèle analytique ainsi obtenu permet d'estimer aisément les champs sans avoir besoin de discrétiser ni le support de transmission ni l'espace d'observation. Pour enrichir notre modèle nous avons ensuite envisagé les cas où la distribution du courant le long des conducteurs était issu, soit de la théorie des lignes soit d'une simulation numérique basée sur la théorie des antennes, soit de mesures. Dans le cas où c'est la théorie des lignes qui est à la base de la détermination des courants distribués, nous proposons un formalisme analytique du champ électromagnétique rayonné basé uniquement sur la seule connaissance des courants et de leurs dérivées aux extrémités des conducteurs. Nous avons également montré que ce formalisme s'extrapole aisément au cas d'un réseau multifilaire. Dans le cas où la théorie des antennes ou des mesures sont à la base de la connaissance des courants distribués, on identifie ce courant par quelques pôles et résidus grâce à la méthode d'identification Matrix Pencil (MP). Le champ électromagnétique rayonné s'exprime alors par une série finie de termes intégrales. Ce formalisme reste analytique et présente l'avantage d'être adapté aux approches paramétriques et d'optimisations. Nos travaux de recherche ouvrent des perspectives de reconstruction de la distribution du courant par Matrix Pencil à partir de la connaissance du courant et de ses premières dérivées spatiales aux seules extrémités des conducteurs. Le champ électromagnétique rayonné sera alors déduit de notre modèle.

Le déploiement d'une infrastructure de supervision permet une gestion plus intelligente des réseaux de distribution d'électricité comparé à un renforcement traditionnel pour répondre aux nouveaux enjeux de la maitrise de l'énergie (Consommations, EnR, VE, ...). Pour acheminer les données, les Courants Porteurs en Ligne (CPL) possèdent un atout majeur. En effet, cette technologie permet de superposer un signal de plus haute fréquence au signal électrique 50/60 Hz. Toutefois, le support de transmission est difficile et non maîtrisable. Ces travaux de recherche ont pour objectif d'apporter une contribution à cette problématique par l'élaboration d'une plateforme de simulation des réseaux pour des fréquences allant jusqu'à 1 MHz dans un but de transmission de données. Des éléments clés des réseaux sont traités de façon séparés puis assemblés pour estimer les performances des CPL « Outdoor » actuels. La variation du comportement des réseaux en fonction du temps et de la fréquence, en particulier des perturbations en tête d'installation clients sur 24h est étudiée. Les transformateurs entre les réseaux HTA et BT sont modélisés sous la forme d'un « modèle à constantes localisées » et d'un « modèle boite noire ». Les deux modèles sont appliqués sur un transformateur H61 100 kVA. Par la suite, une modélisation des câbles de distribution est proposée sous forme d'un « modèle cascadé ». Celle-ci est appliquée sur un câble souterrain BT. Chaque modèle est obtenu à l'aide de mesures d'impédances, et validé par des mesures de transmissions. Pour compléter, une étude préliminaire sur les communications radio mobile est réalisée pour la supervision des réseaux de distribution
Establishing a supervisory infrastructure allows a better smart management than an expensive strengthening of distribution network to respond to new constraints at the energies control (Consumption, REN, EV ...). To transmit data, Power Line Communication (PLC) technologies present an advantage in this context. In fact, it enables a superposition of High Frequency (HF) signals on electrical signal 50/60 Hz. However, electric networks have not been developed to this application because of difficult propagation conditions. This research work makes a contribution to develop a simulation platform in objective to transmit data to 1 MHz. In first time, each network element is studied singly and in second time, together, to estimate "Outdoor PLC" transmission performance. The first element studied is the networks variation in function of frequency and time. Several 24h disturbance measurements on LV customers are presented. The second element is the transformers which established connection between Medium Voltage (MV) and Low Voltage (LV). The proposed modeling method is based on a "lumped model" and a "black box model". These models are applied to a 100 kVA H61 transformer most commonly used by French distribution system operator in rural and suburban networks. The third element is the power line used in MV and LV networks. The proposed modeling method is based on a "cascaded model" from the theory of transmission line. This model is applied to one power line used in LV underground network. Each model is obtained from various impedance measurements. To complete, an introductory study on mobile radio communication is performed to remote network distribution

Actuellement, la distribution à bord des aéronefs de l’énergie électrique en haute tension continue (HVDC) et l'utilisation de technologies de rupture telle que l’utilisation des semi-conducteurs à grand gap (SiC et GaN) dans les convertisseurs statiques sont parmi les leviers indispensables pour le développement de l’avion plus électrique. L'utilisation des semi-conducteurs à grand gap augmente la densité massique des convertisseurs ; cependant, leurs commutations rapides (quelques dizaines de ns) favorisent la création de surtensions dues aux phénomènes de propagation et de réflexion le long des harnais. Les surtensions peuvent dépasser le double de la tension du bus DC ; un tel niveau de tension, combiné avec les contraintes aéronautiques (basse pression et/ou haute température) peut engendrer des phénomènes de décharges partielles (DP) pouvant causer une dégradation prématurée du système d’isolation électrique (SIE). Dans ce contexte, les travaux de cette thèse concernent la fiabilité d’une chaine électromécanique (association : onduleur à MOSFET-SiC + harnais long + machine électrique) alimentée par le réseau HVDC 540V ; ils visent à intégrer la prévention des DP dans le bobinage d’une machine électrique dès les premières phases de conception. D’une part, ces travaux de recherche visent à maitriser les surtensions, et pour cela nous proposons un modèle prédictif et large bande fréquentielle d’une chaine électromécanique triphasée ; sa bonne précision validée expérimentalement permet une meilleure compréhension des phénomènes de surtension, notamment, vis-à-vis de la commutation rapide de la technologie SiC. Le modèle proposé adopte une résolution fréquentielle à faible temps de calcul, ce qui est adapté à une utilisation dans des outils de conception par optimisation. D’autre part, pour pouvoir tenir compte des DP dès la phase de conception, il est essentiel de connaitre le seuil d’apparition des décharges partielles (SADP) en fonction des paramètres de SIE (matériaux isolants, épaisseur) et des paramètres environnementaux (pression, température) : pour ce faire, nous proposons d’améliorer la formule analytique de DAKIN de calcul du SADP dans une approche regroupant des données bibliographiques et les résultats d’une vaste investigation expérimentale
Currently, the distribution of electrical energy aboard aircraft with high voltage direct current (HVDC) and the use of disruptive technologies such as wide bandgap (WBG) semiconductors (SiC and GaN) in static converters are among essential levers for the development of more electric aircraft. Using WBG semiconductors increases the mass density of converters; however, their fast switching (a few tens of ns) induces the creation of overvoltage due to propagation and reflection phenomena along harnesses. Overvoltage can exceed twice the voltage of the DC bus: such voltage level combined with aeronautical constraints (low pressure and/or high temperature) can generate partial discharges (PD) phenomena, which causes a premature degradation of electrical insulation systems (EIS). In this context, this PhD work focuses on the reliability of an electromechanical chain (association: MOSFET-SiC inverter + long harness + electrical machine) supplied by the HVDC 540V network; they aim to prevent the presence of PD in the winding of electrical machine from the early stage of design. On the one hand, this research aims to manage overvoltage, and for this, we develop a predictive, wide-band frequency model of a three-phase electromechanical chain; its good precision, experimentally validated, allows a better understanding of overvoltage phenomena, in particular, according to the fast switching of SiC technology. The proposed model adopts a frequency resolution with low computation time, which is suitable for use in design tools based on optimization algorithms. On the other hand, to be able to take PD into account from the first design stages, it is essential to integrate the knowledge of the partial discharges inception voltage (PDIV) according to the EIS parameters (insulating materials, thickness) and environmental parameters (pressure, temperature). In this scope, we propose to improve PDIV DAKIN's analytical formula using bibliographic data together with the results of a vast experiential investigation

Robust control is an aspect of control theory which explicitly considers uncertainties and how they affect robust stability in the analysis and design of control decisions. A basic requirement for optimal robust guaranteed control in a real life scenario is the stabilization of systems in the presence of uncertainties or perturbations. In this thesis, the system uncertainties are embedded into a norm bounded uncertainty elements. The perturbation function is modelled as a class of nonlinear uncertainty influencing a neutral system with infinite delay. It is assumed to have delay in state and is input dependent; which implies the effect of control action can directly or indirectly influence the nonlinear perturbation function. In recognition of the fact that stability and controllability are fundamental in obtaining the optimal robust guaranteed cost control design for neutral functional integro-differential systems with infinite delays (NFDSID), total asymptotic stability results were developed using Razumikhin technique, unique properties of eigenvalues, and the uniform stability properties of the functional difference operator for neutral systems. The new results, obtained using Razumikhin’s technique, extend and complement basic stability results in neutral systems to NFDSID. Novel sufficient conditions were developed for the null controllability of nonlinear NFDSID when the controls are constrained. By exploring the knowledge gained through other controllability results; conditions are placed on the perturbation function. This guaranteed that, if the uncontrolled system is uniformly asymptotically stable, and the controlled system satisfies a full rank condition, then the control system is null controllable with constraint if it satisfies some algebraic conditions. The investigation of optimal robust guaranteed cost control method has resulted in a novel delay dependent stability criterion for a nonlinear NFDSID with a given quadratic cost function. The new design is based on a model transformation technique, Lyapunov matrix equation and Lyapunov-Razumikhin stability approach. The Lyapunov-Razumikhin technique is adopted for this investigation because it is considered more scalable for optimal robust guaranteed cost control design for NFDSID. It is demonstrated that a memory less feedback control can be synthesized appropriately to ensure: (i) the closed-loop systems robust stability, and (ii) guarantee that the closed-loop cost function value remains within a specified bound. The problem of designing the optimal guaranteed cost controller is also realized in terms of inequalities. The Lyapunov-Krasovskii method is used to obtain stability conditions in comparison to the Razumikhin method. This method leads to linear matrix inequality (LMI) for the delay-independent case which is known to be conservative. To illustrate the potential practical applicability of the theoretical results; a cascade connection of two fully filled chemical solution mixers, and an integrated lossless transmission line which has a capacitance, inductance, resistance and terminated by a nonlinear function are modelled. A neutral control system model for NFDSID is derived from each of these systems. Simulation studies on the transmission line system confirm the theoretical robust stability results. The new results and methods of analysis expounded in this thesis are explicit, computationally more effective than existing ones and will serve as a working document for the present and future generations in the comity of researchers and industries alike.

Thesis (M.S.)--University of Missouri--Rolla, 2007.
Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 26, 2007) Includes bibliographical references (p. 112-113).

The dissertation presents theoretical and experimental studies on the physical origin of the signal in photothermal microscopy of single particles. This noninvasive optical far field microscopy scheme allows the imaging and detection of single absorbing nanoparticles. Based on a heat-induced pertur- bation in the refractive index in the embedding medium of the nanoscopic absorber, a corresponding probe beam modification is measured and quantified. The method is well established and has been applied since its first demonstration in 2002 to the imaging and characterization of various absorbing particle species, such as quantum dots, single molecules and nanoparticles of different shapes. The extensive theoretical developments presented in this thesis provide the first quantitative assess- ment of the signal and at the same time enlarge its phenomenology and thereby its potential. On the basis of several approximation schemes to the Maxwell equations, which fundamentally gov- ern the interaction of light with inhomogeneities, several complementing models are devised which describe the photothermal signal both qualitatively and quantitatively. In succession an interdepen- dent and self-consistent set of theoretical descriptions is given and allows important experimental consequences to be drawn. In consequence, the photothermal signal is shown to correspond to the action of a nanoscopic (thermal) lens, represented by the spherically symmetric refractive index pro- file n(r) which accompanies the thermal expansion of the absorber’s environment. The achieved quantification allows the direct measurement of absorption cross-sections of nanoparticles. Further, a qualitatively new phenomenology of the signal is unraveled and experimentally demonstrated. The separate roles of the probing and the heating beams in photothermal microscopy is dismantled and the influence of their relative alignment shown to allow for a controlled adjustment of the effective detection volume. For the first time, both positive and negative signals are demonstrated to occur and to be the characteristic signature of the lens-like action on the probe beam. The detection of the probe beam’s modification is also shown to sensitively depend on the aperture used in the detection chan- nel, and a signal optimization is shown to be feasible. Also, a generalization of the detectable signal via the use of a quadrant photodiode is achieved. Specifically, measuring the far field beam deflec- tion the result of the beam passing the lens off-center manifests in a laterally split detection volume. Hereby, finally each classical photothermal spectroscopic techniques has been shown to possess its microscopic counterpart. Central to the understanding of this generalized and new phenomenology is a scalar wave-optical model which draws an analogy between the scattering of a massive particle wave-packet by a Coulomb potential and the deflection of a focused beam by a photonic potential connected with the thermal lens. The significance of the findings is demonstrated by its methodological implications on photother- mal correlation spectroscopy in which the diffusion dynamics of absorbing colloidal particles can be studied. The unique split focal detection volumes are shown to allow the sensitive measurement of a deterministic velocity field. Finally, the method is supplemented by a newly introduced sta- tistical analysis method which is capable of characterizing samples containing a heterogeneous size distribution.

Includes bibliographies.
This study resulted from a perception held by the author that more attention is afforded to complying with the procedural elements of Environmental Impact Assessment (EIA) in South Africa, than to ensuring the validity of its technical content. The routing of high voltage overhead transmission lines provides a relevant field of study in which to address this perception. An initial literature review to contextualise the perceived problem showed that the questionable validity of the technical content of EIA was one of six shortcomings identified. To address the problem, an inductive approach was adopted to focus on the interpretation and prediction activities of EIA and two propositions, stated as research questions for discussion, were developed. These referred to the theoretical question of whether methods are specified for high voltage overhead transmission line EIAs, and to the practical question of whether the environmental impacts that are known to result from transmission line projects are effectively addressed in such EIAs in South Africa. Investigating these questions provides insights into whether the technical content of transmission line EIA is sufficiently rigorous in South Africa. The method of study takes the form of a sequentially more focused examination of the literature on EIA, from the strategic level, to the sectoral level and culminating at the project level. EIA methods specified for linear developments were identified at the sectoral level, while at the project level the known environmental impacts that result from high voltage overhead transmission lines were determined. A theoretical background was compiled in this way, which allowed for comparison with the practice as determined from benchmark and case study Environmental Impact Reports (EIRs).

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico
This paper presents an automatic fault location method in transmission lines based on the Travelling Waves Theory (TWT) using the Stockwell Transform (ST) to determine the travelling waves propagation time and the dominant frequency of transient signals generated by faults. The method considers the case where there is no communication between terminals or loss of synchronism between the devices responsible for estimating the location of faults using, therefore, only data from one terminal. Single-phase faults only involving one of the phases and the earth area evaluated, which occur in the first half of a transmission line of unknown parameters. It is observed that the method (i) wasnât sensitive to fault resistance variations and inception angle and (ii) the obtained results presented errors between 0,10% and 5,82% for faults that occurred between 7km and 99km from the monitoring terminal. To improve the accuracy of estimating the fault location, an Artificial Neural Network (ANN) of the type MLP (Multi-Layer Perceptron) is designed, and trained with characteristics extracted from the faulty signals using ST. The ATP (Alternative Transient Program) software was adopted for simulation of a three phase transmission line which voltage signals were sampled at 200kHz. The simulations were performed exploring 1280 combinations of the following parameters: fault locations, fault resistances and inception angle. The method was developed using the software MATLABÂ. According to the obtained results, the combination of ST with ANN presented better results than the application of ST and TWT. Such improvement is highlighted for the estimation of fault location at greater distances from the monitoring terminal, with errors between 0,02% and 1,56% for faults that occurred between 7km and 99km from the monitoring terminal.
Este trabalho apresenta um mÃtodo automÃtico de localizaÃÃo de faltas em linhas de transmissÃo baseado na Teoria das Ondas Viajantes (TOV) utilizando a Transformada de Stockwell (TS) para determinaÃÃo dos tempos de propagaÃÃo das ondas viajantes e da frequÃncia dominante dos sinais transitÃrios gerados pelas situaÃÃes de falta. O mÃtodo considera o caso em que nÃo hà comunicaÃÃo entre terminais ou hà perda de sincronismo entre os equipamentos responsÃveis pela estimaÃÃo da localizaÃÃo das faltas utilizando, portanto, dados provenientes de apenas um terminal. Consideram-se faltas monofÃsicas envolvendo uma das fases e a terra, as quais ocorrem na primeira metade de uma linha de transmissÃo de parÃmetros desconhecidos. Observa-se que o mÃtodo (i) nÃo se mostrou sensÃvel a variaÃÃes de resistÃncia de falta e Ãngulo de incidÃncia e (ii) os resultados obtidos apresentam erros entre 0,10% e 5,82% para faltas que ocorreram entre 7km e 99km do terminal de monitoramento. Para a melhoria da precisÃo na estimaÃÃo da localizaÃÃo das faltas foi projetada uma Rede Neural Artificial (RNA) do tipo MLP (Multi-Layer Perceptron), treinada a partir de caracterÃsticas dos sinais faltosos extraÃdas atravÃs da TS. Foram utilizados os sinais trifÃsicos de tensÃo amostrados na frequÃncia de 200kHz gerados a partir de simulaÃÃes no software ATP (Alternative Transiente Program), no qual foram realizadas 1280 simulaÃÃes explorando diversas localizaÃÃes e resistÃncias de falta e Ãngulo de incidÃncia. O mÃtodo foi aplicado utilizando o software MATLABÂ. De acordo com os resultados obtidos, a combinaÃÃo da TS e RNA projetada apresentou melhores resultados do que a aplicaÃÃo da TS e TOV, destacando-se na estimaÃÃo da localizaÃÃo de faltas que ocorreram a maiores distÃncias do terminal de monitoramento, com erros entre 0,02% e 1,56% para faltas que ocorreram entre 7km e 99km do terminal de monitoramento.

The remarkable evolution of wireless networks into the next generation to provide ubiquitous and seamless broadband applications has recently triggered the emergence of Wireless Mesh Networks (WMNs). The WMNs comprise stationary Wireless Mesh Routers (WMRs) forming Wireless Backbone Mesh Networks (WBMNs) and mobile Wireless Mesh Clients (WMCs) forming the WMN access. While WMCs are limited in function and radio resources, the WMRs are expected to support heavy duty applications : that is, WMRs have gateway and bridge functions to integrate WMNs with other networks such as the Internet, cellular, IEEE 802.11, IEEE 802.15, IEEE 802.16, sensor networks, et cetera. Consequently, WMRs are constructed from fast switching radios or multiple radio devices operating on multiple frequency channels. WMRs are expected to be self-organized, self-configured and constitute a reliable and robust WBMN which needs to sustain high traffic volumes and long "online" time. However, meeting such stringent service expectations requires the development of decentralized dynamic transmission power control (DTPC) approaches. This thesis addresses the DTPC problem for both single and multiple channel WBMNs. For single channel networks, the problem is formulated as the minimization of both the link-centric and network-centric convex cost function. In order to solve this issue, multiple access transmission aware (MATA) models and algorithms are proposed. For multi-radio multi-channel (MRMC) WBMNs, the network is modelled as sets of unified channel graphs (UCGs), each consisting of interconnected active network users communicating on the same frequency channel. For each UCG set, the minimization of stochastic quadratic cost functions are developed subject to the dynamic Link State Information (LSI) equations from all UCGs. An energy-efficient multi-radio unification protocol (PMMUP) is then suggested at the Link-Layer (LL). Predictive estimation algorithms based on this protocol are proposed to solve such objective functions. To address transmission energy and packet instabilities, and interference across multiple channels, singularly-perturbed weakly-coupled (SPWC) control problems are formulated. In order to solve the SPWC transmission power control problem, a generalized higher-order recursive algorithm (HORA) that obtains the Riccati Stabilizing Solutions to the control problem is developed. The performance behaviours of the proposed models and algorithms are evaluated both analytically and through computer simulations. Several simulations are performed on a large number of randomly generated topologies. Simulation and analytical results confirm the efficacy of the proposed algorithms compared to the most recently studied techniques

[EN] Phononic crystals are artificial materials formed by a periodic arrangement of inclusions embedded into a host medium, where each of them can be solid or fluid. By controlling the geometry and the impedance contrast of its constituent materials, one can control the dispersive properties of waves, giving rise to a huge variety of interesting and fundamental phenomena in the context of wave propagation. When a propagating wave encounters a medium with different physical properties it can be transmitted and reflected in lossless media, but also absorbed if dissipation is taken into account. These fundamental phenomena have been classically explained in the context of homogeneous media, but it has been a subject of increasing interest in the context of periodic structures in recent years as well. This thesis is devoted to the study of different effects found in sonic and phononic crystals associated with transmission, reflection and absorption of waves, as well as the development of a technique for the characterization of its dispersive properties, described by the band structure. We start discussing the control of wave propagation in transmission in conservative systems. Specifically, our interest is to show how sonic crystals can modify the spatial dispersion of propagating waves leading to control the diffractive broadening of sound beams. Making use of the spatial dispersion curves extracted from the analysis of the band structure, we first predict zero and negative diffraction of waves at frequencies close to the band-edge, resulting in collimation and focusing of sound beams in and behind a 3D sonic crystal, and later demonstrate it through experimental measurements. The focusing efficiency of a 3D sonic crystal is limited due to the strong scattering inside the crystal, characteristic of the diffraction regime. To overcome this limitation we consider axisymmetric structures working in the long wavelength regime, as a gradient index lens. In this regime, the scattering is strongly reduced and, in an axisymmetric configuration, the symmetry matching with acoustic sources radiating sound beams increase its efficiency dramatically. Moreover, the homogenization theory can be used to model the structure as an effective medium with effective physical properties, allowing the study of the wave front profile in terms of refraction. We will show the model, design and characterization of an efficient focusing device based on these concepts. Consider now a periodic structure in which one of the parameters of the lattice, such as the lattice constant or the filling fraction, gradually changes along the propagation direction. Chirped crystals represent this concept and are used here to demonstrate a novel mechanism of sound wave enhancement based on a phenomenon known as "soft" reflection. The enhancement is related to a progressive slowing down of the wave as it propagates along the material, which is associated with the group velocity of the local dispersion relation at the planes of the crystal. A model based on the coupled mode theory is proposed to predict and interpret this effect. Two different phenomena are observed here when dealing with dissipation in periodic structures. On one hand, when considering the propagation of in-plane sound waves in a periodic array of absorbing layers, an anomalous decrease in the absorption, combined with a simultaneous increase of reflection and transmission at Bragg frequencies is observed, in contrast to the usual decrease of transmission, characteristic in conservative periodic systems at these frequencies. For a similar layered media, backed now by a rigid reflector, out-of-plane waves impinging the structure from a homogeneous medium will increase dramatically the interaction strength. In other words, the time delay of sound waves inside the periodic system will be considerably increased resulting in an enhanced absorption, for a broadband spectral range.
[ES] Los cristales fonónicos son materiales artificiales formados por una disposición periódica de inclusiones en un medio, pudiendo ambos ser de carácter sólido o fluido. Controlando la geometría y el contraste de impedancias entre los materiales constituyentes se pueden controlar las propiedades dispersivas de las ondas. Cuando una onda propagante se encuentra un medio con diferentes propiedades físicas puede ser transmitida y reflejada, en medios sin pérdidas, pero también absorbida, si la disipación es tenida en cuenta. La presente tesis está dedicada al estudio de diferentes efectos presentes en cristales sónicos y fonónicos relacionados con la transmisión, reflexión y absorción de ondas, así como el desarrollo de una técnica para la caracterización de sus propiedades dispersivas, descritas por la estructura de bandas. En primer lugar, se estudia el control de la propagación de ondas en transmisión en sistemas conservativos. Específicamente, nuestro interés se centra en mostrar cómo los cristales sónicos son capaces de modificar la dispersión espacial de las ondas propagantes, dando lugar al control del ensanchamiento de haces de sonido. Haciendo uso de las curvas de dispersión espacial extraídas del análisis de la estructura de bandas, se predice primero la difracción nula y negativa de ondas a frecuencias cercanas al borde de la banda, resultando en la colimación y focalización de haces acústicos en el interior y detrás de un cristal sónico 3D, y posteriormente se demuestra mediante medidas experimentales. La eficiencia de focalización de un cristal sónico 3D está limitada debido a las múltiples reflexiones existentes en el interior del cristal. Para superar esta limitación se consideran estructuras axisimétricas trabajando en el régimen de longitud de onda larga, como lentes de gradiente de índice. En este régimen, las reflexiones internas se reducen fuertemente y, en configuración axisimétrica, la adaptación de simetría con fuentes acústicas radiando haces de sonido incrementa la eficiencia drásticamente. Además, la teoría de homogenización puede ser empleada para modelar la estructura como un medio efectivo con propiedades físicas efectivas, permitiendo el estudio del frente de ondas en términos refractivos. Se mostrará el modelado, diseño y caracterización de un dispositivo de focalización eficiente basado en los conceptos anteriores. Considérese ahora una estructura periódica en la que uno de los parámetros de la red, sea el paso de red o el factor de llenado, cambia gradualmente a lo largo de la dirección de propagación. Los cristales chirp representan este concepto y son empleados aquí para demostrar un mecanismo novedoso de incremento de la intensidad de la onda sonora basado en un fenómeno conocido como reflexión "suave". Este incremento está relacionado con una ralentización progresiva de la onda conforme se propaga a través del material, asociado con la velocidad de grupo de la relación de dispersión local en los planos del cristal. Un modelo basado en la teoría de modos acoplados es propuesto para predecir e interpretar este efecto. Se observan dos fenómenos diferentes al considerar pérdidas en estructuras periódicas. Por un lado, si se considera la propagación de ondas sonoras en un array periódico de capas absorbentes, cuyo frente de ondas es paralelo a los planos del cristal, se produce una reducción anómala en la absorción combinada con un incremento simultáneo de la reflexión y transmisión a las frecuencias de Bragg, de forma contraria a la habitual reducción de la transmisión, característica de sistemas periódicos conservativos a estas frecuencias. En el caso de la misma estructura laminada en la que se cubre uno de sus lados mediante un reflector rígido, la incidencia de ondas sonoras desde un medio homogéneo, cuyo frente de ondas es perpendicular a los planos del cristal, produce un gran incremento de la fuerza de
[CAT] Els cristalls fonònics són materials artificials formats per una disposició d'inclusions en un medi, ambdós poden ser sòlids o fluids. Controlant la geometría i el contrast d'impedàncies dels seus materials constituents, és poden controlar les propietats dispersives de les ondes, permetent una gran varietatde fenòmens fonamentals interessants en el context de la propagació d'ones. Quan una ona propagant troba un medi amb pèrdues amb propietats físiques diferents es pot transmetre i reflectir, però també absorbida si la dissipació es té en compte. Aquests fenòmens fonamentals s'han explicat clàssicament en el context de medis homogenis, però també ha sigut un tema de creixent interés en el context d'estructures periòdiques en els últims anys. Aquesta tesi doctoral tracta de l'estudi de diferents efectes en cristalls fonònics i sònics lligats a la transmissió, reflexió i absorció d'ones, així com del desenvolupament d'una tècnica de caracterització de les propietats dispersives, descrites mitjançant la estructura de bandes. En primer lloc, s'estudia el control de la propagació ondulatori en transmissió en sistemes conservatius. Més específicament, el nostre interés és mostrar com els cristalls sonors poden modificar la dispersió espacial d'ones propagants donant lloc al control de l'amplària per difracció dels feixos sonors. Mitjançant les corbes dispersió espacial obtingudes de l'anàlisi de l'estructura de bandes, es prediu, en primer lloc, la difracció d'ones zero i negativa a freqüències próximes al final de banda. El resultat és la collimació i focalització de feixos sonors dins i darrere de cristalls de so. Després es mostra amb mesures experimentals. L'eficiència de focalització d'un cristall de so 3D està limitada per la gran dispersió d'ones dins del cristall, que és característic del règim difractiu. Per a superar aquesta limitació, estructures axisimètriques que treballen en el règim de llargues longituds d'ona, i es comporten com a lents de gradient d'índex. En aquest règim, la dispersió es redueix enormement i, en una configuració axisimètrica, a causa de l'acoblament de la simetría amb les fonts acústiques que radien feixos sonors, l'eficiència de radiació s'incrementa significativament. D'altra banda, la teoria d'homogeneïtzació es pot utilitzar per a modelar, dissenyar i caracteritzar un dispositiu eficient de focalització basat en aquests conceptes. Considerem ara una estructura periòdica en la qual un dels seus paràmetres de xarxa, com ara la constant de xarxa o el factor d'ompliment canvia gradualment al llarg de la direcció de propagació. Els cristalls chirped representen aquest concepte i s'utilitzen ací per a demostrar un mecanisme nou d'intensificació d'ones sonores basat en el fenòmen conegut com a reflexió "suau". La intensificació està relacionada amb la alentiment progressiva de l'ona conforme propaga al llarg del material, que està associada amb la velocitat de grup de la relació de dispersió local en els diferents plànols del cristall. Es proposa un model basat en la teoria de modes acoblats per a predir i interpretar este efecte. Dos fenòmens diferents cal destacar quan es tracta d'estructures periòdiques amb dissipació. Per un costat, al considerar la propagació d'ones sonores en el plànol en un array periòdic de capes absorbents, s'observa una disminució anòmala de l'absorció i es combina amb un augment simultani de reflexió i transmissió en les freqüències de Bragg que contrasta amb la usual disminució de transmissió, característica dels sistemes conservatius a eixes freqüències. Per a un medi similar de capes, amb un reflector rígid darrere, les ones fora del pla incidint l'estructura des de un medi homogeni, augmentaran considerablement la interacció. En altres paraules, el retràs temporal de les ones sonores dins del sistema periòdic augmentarà significativament produint un augmen
Cebrecos Ruiz, A. (2015). Transmission, reflection and absorption in Sonic and Phononic Crystals [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/56463
TESIS
Premiado

In this thesis we present new approaches in the domains of soft fault detection and location in complex wire networks, based on the properties of time reversal. When addressing the detection of soft faults, the idea is to adapt the testing signal to the network under test, instead of being predefined for all the tested networks, as opposed to standard reflectometry techniques. We prove that this approach, which we name the Matched Pulse approach (MP), is beneficial whenever the system is more complex, i.e., its response is richer in echoes, which is opposed to common understanding. The MP analysis is conducted via a formal mathematical analysis, followed by simulation and experimental results validating the proposed approach. In the domain of soft fault location, and based on the DORT (Décomposition de l'Opérateur de Retournement Temporel) properties, we derive a distributive non-iterative method able to synthesize signals that focus on the fault position. Through a statistical study we analyze some of the influencing parameters on the performance of the method, and then simulation and experimental results show that the method is able to synthesize signals directly focalizing on the soft fault position, without the need for iterations.

De nos jours, nous assistons à une forte évolution des systèmes modernes de la communication sans fil, exploitant des fréquences très élevées, dans la bande des fréquences micro-ondes. De ce fait, pour éviter des architectures compactes des systèmes électroniques composant ces systèmes modernes, apparaît la nécessité d'envisager la communication sans fil entre les circuits imprimés intégrés aux systèmes électroniques.Les principaux problèmes rencontrés dans ces systèmes concernent l'effet de l'environnement sur la communication sans fil et la protection contre les effets indésirables. Cela exige de nouvelles techniques de simulation et de modélisation du champ EM dans ces environnements complexes, pour une prédiction de leurs comportements.Avec les expériences effectuées dans le domaine des micro-ondes, ces techniques seront possibles en se basant sur la théorie des matrices aléatoires (TMA), bien adaptée dans ces situations de milieu complexe.Les travaux effectués au cours de cette thèse présentent :Dans un premier temps, l'illustration d'un exemple d'une telle situation où tous les ingrédients sont présents (circuit imprimé, lignes de transmissions et cavité). Nous avons présenté une étude expérimentale, qui met en évidence l'effet de l'environnement partiellement réverbérant sur la diaphonie entre les lignes imprimées, de sorte que leurs courants ne soient pas négligés et doivent être pris en compte, pour la conception appropriée de circuit imprimé, garantissant leur fonctionnement.Dans un second temps, dans le but d'étudier et d'analyser statistiquement le comportement de la transmission à l'intérieur d'un milieu complexe, nous avons réalisé une chambre réverbérante chaotique (CRC), qui satisfait aux critères statistiques fixés par la norme internationale. Le critère principal exige d'avoir une uniformité et isotropie statistique du champ à l'intérieur de la CRC et que les composantes du champ suivent une distribution gaussienne bivariée. Dans la communauté de la Compatibilité d'Électromagnétique (CEM), on parle de l'hypothèse de Hill, typiquement réalisée quand le recouvrement modal est grand. Nous avons étudié expérimentalement plusieurs statistiques de la réponse de la CRC et les effets du régime de fort recouvrement modal sur les distributions de la réflexion et la transmission, puis nous les avons comparées aux prédictions numériques prévues par la TMA.Nous avons également vérifié la relation de l'espacement moyen entre les maxima de transmission prédite par Schroeder et Kuttruff pour un régime fort recouvrement modal, dans les salles acoustiques.Dans un troisième temps, nous avons développé une nouvelle méthode pour l'estimation de nombre d'échantillons non corrélés (NIS) dans une CRC. Puis nous avons suggéré une perspective pour l'estimation de NIS, basée sur l'échelle caractéristique de la dynamique des maxima en fonction de l'angle de brasseur
Nowadays, modern wireless communication systems that are operating at high frequencies in the microwave band, are massively emerging. To avoid compact architectures of electronic systems, we explore wireless communication between printed circuits integrated into the electronic systems. Several problems encountered in these systems are related to the effect of the environment on wireless communication and the protection against adverse effects. This requires new electromagnetic simulation techniques to describe the field and the system response in these environments. Along with the microwave experiments, random matrix theory (RMT) enables to theoretically study wireless communication in complex environment.This manuscrit is diveded in three main topics:On the one hand, an illustration of the situation where all the ingredients are implemented namely, a Printed Circuit Board (PCB) with transmission lines inside a cavity. I present an experimental study, which highlights the effect of the partially reverberating environment on the crosstalk of two printed lines, as well as the currents on these lines. The latter should be taken into account to guarantee the proper functioning of the PCB.On the other hand, a chaotic reverberating chamber (CRC) was designed to statistically analyze the behavior of the transmission inside a complex environment. The international standard fix several statistical criteria with which the RC have to comply. Fulfilling all criteria guarantees that the field inside the cavity is isotropic and the field components follow a bivariate Gaussian distribution. In the electromagnetic community, this is the so-called Hill’s hypothesis. This hypothesis is typically realized when the resonance overlap is large. I have experimentally studied several statistic properties of the electromagnetic response in a CRC. The effects of the modal overlap on the reflection and the transmission distributions have been analyzed. In addition to this, we have compared the experimental distributions to numerical predictions based on Random Matrix Theory. I also verified the relation between the mean frequency spacing of the maxima and the average decay rate of the cavity predicted by Schroeder and Kuttruff for a high modal overlap in acoustic rooms.Finaly, we have developed a new method to estimate the number of uncorrelated samples (NIS) in a CRC. We have suggested a perspective for NIS estimation based on the characteristic scale of maxima dynamics as a function of the stirrer angle

Orientador: Reginaldo Palazzo Junior
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
Made available in DSpace on 2018-08-04T17:37:04Z (GMT). No. of bitstreams: 1 Souza_MarioJosede_D.pdf: 1221200 bytes, checksum: f5bf0643e72a350fca4e873f9d0e91e2 (MD5) Previous issue date: 2005
Resumo: Neste trabalho apresentamos uma linha de transmissão como uma modelagem hiperbólica; construímos constelações de sinais hiperbólicas a partir das tesselações regulares do tipo {12g - 6, 3}; estabelecemos um procedimento para a contagem do número de pontos (sinais) das constelações acima citadas e apresentamos as funções automorfas como um meio de trânsito entre o ambiente das linhas de transmissão (semiplano direito) e o ambiente das constelações construídas (as superfícies de Riemann)
Abstract: In this work we have introduced a transmission line as a hyperbolic modeling; we have constructed a signal constellation in the hyperbolic plane from regular tessellations such as the ones generated by {12g - 6, 3} ; we have established a procedure for couting the number of points of the constellations mentioned above. We have also presented the automorphic functions as a means of transit between the context of transmission line (right semiplane) and the context of the constellations which were built (Riemann's surfaces)
Doutorado
Telecomunicações e Telemática
Doutor em Engenharia Elétrica

This thesis tackles issues of particular interest regarding analysis and design of passive components at the mm-wave and Terahertz (THz) bands. Innovative analysis techniques and modeling of complex structures, design procedures, and practical implementation of advanced passive devices are presented. The first part of the thesis is dedicated to THz passive components. These days, THz technology suffers from the lack of suitable waveguiding structures since both, metals and dielectric, are lossy at THz frequencies. This implies that neither conventional closed metallic structures used at microwave frequencies, nor dielectric waveguides used in the optical regime, are adequate solutions. Among a variety of new proposals, the Single Wire Waveguide (SWW) stands out due to its low attenuation and dispersion. However, this surface waveguide presents difficult excitation and strong radiation on bends. A Dielectric-Coated Single Wire Waveguide (DCSWW) can be used to alleviate these problems, but advantages of the SWW are lost and new problems arise. Until now, literature has not given proper solution to radiation on bends and, on the other hand, rigorous characterization of these waveguides lacks these days. This thesis provides, for the first time, a complete modal analysis of both waveguides, appropriated for THz frequencies. This analysis is later applied to solve the problem of radiation on bends. Several structures and design procedures to alleviate radiation losses are presented and experimentally validated. The second part of the thesis is dedicated to mm-wave passive components. These days, when implementing passive components to operate at such small, millimetric wavelengths, to ensure proper metallic contact and alignment between parts results challenging. In addition, dielectric absorption becomes significant at mm-wave frequencies. Consequently, conventional hollow metallic waveguides and planar transmission lines present high attenuation so that new topologies are being considered. Gap Waveguides (GWs), based on a periodic structure introducing an Electromagnetic Bandgap effect, result very suitable since they do not require metallic contacts and avoid dielectric losses. However, although GWs have great potential, several issues prevent GW technology from becoming consolidated and universally used. On the one hand, the topological complexity of GWs difficulties the design process since full-wave simulations are time-costly and there is a lack of appropriate analysis methods and suitable synthesis procedures. On the other hand, benefits of using GWs instead of conventional structures are required to be more clearly evidenced with high-performance GW components and proper comparatives with conventional structures. This thesis introduces several efficient analysis methods, models, and synthesis techniques that will allow engineers without significant background in GWs to straightforwardly implement GW devices. In addition, several high-performance narrow-band filters operating at Ka-band and V-band, as well as a rigorous comparative with rectangular waveguide topology, are presented.
Esta tesis aborda problemas actuales en el análisis y diseño de componentes pasivos en las bandas de onda milimétrica y Terahercios (THz). Se presentan nuevas técnicas de análisis y modelado de estructuras complejas, procedimientos de diseño, e implementación práctica de dispositivos pasivos avanzados. La primera parte de la tesis se dedica a componentes pasivos de THz. Actualmente no se disponen de guías de onda adecuadas a THz debido a que ambos, metales y dieléctricos, introducen grandes pérdidas. En consecuencia, no es adecuado escalar las estructuras metálicas cerradas usadas en microondas, ni las guías dieléctricas usadas a frecuencias ópticas. Entre un gran número de recientes propuestas, la Single Wire Waveguide (SWW) destaca por su baja atenuación y casi nula dispersión. No obstante, como guía superficial, la SWW presenta difícil excitación y radiación en curvas. El uso de un recubrimiento dieléctrico, creando la Dielecric-Coated Single Wire Waveguide (DCSWW), alivia estos inconvenientes, pero las ventajas anteriores se pierden y nuevos problemas aparecen. Hasta la fecha, no se han encontrado soluciones adecuadas para la radiación en curvas de la SWW. Además, se echa en falta una caracterización rigurosa de ambas guías. Esta tesis presenta, por primera vez, un análisis modal completo de SWW y DCSWW, adecuado a la banda de THz. Este análisis es aplicado posteriormente para evitar el problema de la radiación en curvas. Se presentan y validan experimentalmente diversas estructuras y procedimientos de diseño. La segunda parte de la tesis abarca componentes pasivos de ondas milimétricas. Actualmente, estos componentes sufren una importante degradación de su respuesta debido a que resulta difícil asegurar contacto metálico y alineamiento adecuados para la operación a longitudes de onda tan pequeñas. Además, la absorción dieléctrica incrementa notablemente a estas frecuencias. En consecuencia, tanto guías metálicas huecas como líneas de transmisión planares convencionales presentan gran atenuación, siendo necesario considerar topologías alternativas. Las Gap Waveguides (GWs), basadas en una estructura periódica que introduce un efecto de Electromagnetic Bandgap, resultan muy adecuadas puesto que no requieren contacto entre partes metálicas y evitan las pérdidas en dieléctricos. No obstante, a pesar del potencial de las GWs, varias barreras impiden la consolidación y uso universal de esta tecnología. Por una parte, la compleja topología de las GWs dificulta el proceso de diseño dado que las simulaciones de onda completa consumen mucho tiempo y no existen actualmente métodos de análisis y diseño apropiados. Por otra parte, es necesario evidenciar el beneficio de usar GWs mediante dispositivos GW de altas prestaciones y comparativas adecuadas con estructuras convencionales. Esta tesis presenta diversos métodos de análisis eficientes, modelos, y técnicas de diseño que permitirán la síntesis de dispositivos GW sin necesidad de un conocimiento profundo de esta tecnología. Asimismo, se presentan varios filtros de banda estrecha operando en las bandas Ka y V con altas prestaciones, así como una comparativa rigurosa con la guía rectangular.
Aquesta tesi aborda problemes actuals en relació a l'anàlisi i disseny de components passius en les bandes d'ona mil·limètrica i Terahercis. Es presenten noves tècniques d'anàlisi i modelatge d'estructures complexes, procediments de disseny, i implementació pràctica de dispositius passius avançats. La primera part de la tesi es focalitza en components passius de THz. Actualment no es disposen de guies d'ona adequades a THz causa que tots dos, metalls i dielèctrics, introdueixen grans pèrdues. En conseqüència, no és adequat escalar les estructures metál·liques tancades usades en microones, ni les guies dielèctriques usades a freqüències òptiques. Entre un gran nombre de propostes recents, la Single Wire Waveguide (SWW) destaca per la seua baixa atenuació i quasi nul·la dispersió. No obstant això, com a guia superficial, la SWW presenta difícil excitació i radiació en corbes. L'ús d'un recobriment dielèctric, creant la Dielecric-Coated Single Wire Waveguide (DCSWW), alleuja aquests inconvenients, però els avantatges anteriors es perden i nous problemes apareixen. Fins a la data, no s'han trobat solucions adequades per a la radiació en corbes de la SWW. A més, es troba a faltar una caracterització rigorosa d'ambdues guies. Aquesta tesi presenta, per primera vegada, un anàlisi modal complet de SWW i DCSWW, adequat a la banda de THz. Aquest anàlisi és aplicat posteriorment per evitar el problema de la radiació en corbes. Es presenten i validen experimentalment diverses estructures i procediments de disseny. La segona part de la tesi es centra en components passius d'ones mil·limètriques. Actualment, aquests components pateixen una important degradació de la seua resposta a causa de que resulta difícil assegurar contacte metàl·lic i alineament adequats per a l'operació a longituds d'ona tan menudes. A més, l'absorció dielèctrica incrementa notablement a aquestes freqüències. En conseqüència, tant guies metàl·liques buides com línies de transmissió planars convencionals presenten gran atenuació, sent necessari considerar topologies alternatives. Les Gap Waveguides (GWs), basades en una estructura periòdica que introdueix un efecte de Electromagnetic Bandgap, resulten molt adequades ja que no requereixen contacte entre parts metàl·liques i eviten les pèrdues en dielèctrics. No obstant, tot i el potencial de les GWs, diverses barreres impedixen la consolidació i ús universal d'aquesta tecnologia. D'una banda, la complexa topologia de les GWs dificulta el procés de disseny atés que les simulacions d'ona completa consumeixen molt de temps i no existeixen actualment mètodes d'anàlisi i disseny apropiats. D'altra banda, és necessari evidenciar el benefici d'utilitzar GWs mitjançant dispositius GW d'altes prestacions i comparatives adequades amb estructures convencionals. Aquesta tesi presenta diversos mètodes d'anàlisi eficients, models, i tècniques de disseny que permetran la síntesi de dispositius GW sense necessitat d'un coneixement profund d'aquesta tecnologia. Així mateix, es presenten diversos filtres de banda estreta operant en les bandes Ka i V amb altes prestacions, així com una comparativa rigorosa amb la guia rectangular.
Berenguer Verdú, AJ. (2017). Analysis and design of efficient passive components for the millimeter-wave and THz bands [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/84004
TESIS

碩士
國立清華大學
資訊工程學系
93
As feature size of a circuit decrease, many second order effects such as transient effect of power grid network cannot be ignored during design. In this thesis, we focus on transient effect of power grid network, this transient effects cause voltage fluctuation over power grid network, called IR drop. We survey two approaches to solve/analyze voltage fluctuation over power grid network. The first approach is prediction-based method different from simulated-based approach. We observe that power grid network is isomorphic to a transmission line and we try to predict voltage fluctuation by signal propagation and decay properties without simulating state equation like HSPICE. The other is effect of decoupling capacitance on power grid network, we connect decap effect with transmission line, but relationship between steady state response and transient problem is not clear.

The electromagnetic coupling of a microstrip transmission line (MS-TL) to a metamaterial backward wave Negative-Refractive-Index transmission line (NRI-TL) is the primary investigation of this dissertation. The coupling of forward waves in the MS-TL to the backward waves in the NRI-TL results in the formation of complex modes, characterized by simultaneous phase progression and attenuation along the lossless lines. Through network-theoretic considerations, we investigate the properties of these modes in the complex-frequency plane of the Laplace domain to help unravel the confusion that has existed in the literature regarding the independent excitation of a pair of conjugate complex modes. We show that it is possible to arbitrarily suppress one of the modes over a finite bandwidth and completely eliminate it at a discrete set of frequencies using proper source and load impedances. Hence we use conjugate modes with independent amplitudes in our eigenmode expansion when we analyse various coupling configurations between the two types of lines (MS/NRI-TL coupler). We derive approximate closed-form expression for the scattering parameters of the MS/NRI-TL coupler and these are complemented by design charts that allow the synthesis of a wide range of specifications. Moreover, these expressions reveal that such couplers allow for arbitrary backward coupling levels along with very high-isolation when they are made half a guided wavelength long. The MS/NRI-TL coupler offers some interesting applications which we highlight through the design and testing of a 3-dB power splitter, a high-directivity signal monitor and a compact corporate power divider. We have included design, simulation and experimental data for the fabricated prototypes exhibiting good agreement and thereby justifying the theory that has been developed in this work to explain the coupling between a right-handed MS-TL and a left-handed NRI-TL.

This thesis focuses on the analytical modeling of periodic structures which contain bands with multiple modes of propagation. The work is motivated by several structures which exhibit dual-mode propagation bands. Initially, transmission line models are focused on. Transmission line models of periodic structures have been used extensively in a wide variety of applications due to their simplicity and the ease with which one can physically interpret the resulting wave propagation effects. These models, however, are fundamentally limited, as they are only capable of capturing a single mode of propagation. In this work multiconductor transmission line theory, which is the multi-mode generalization of transmission line theory, is shown to be an effective and accurate technique for the analytical modeling of periodically loaded structures which support multiple modes of propagation. Many results from standard periodic transmission line analysis are extended and generalized in the multiconductor line analysis, providing a familiar intuitive model of the propagation phenomena. The shielded Sievenpiper structure, a periodic multilayered geometry, is analyzed in depth, and provides a canonical example of the developed analytical method. The shielded Sievenpiper structure exhibits several interesting properties which the multiconductor transmission line analysis accurately captures. It is shown that under a continuous change of geometrical parameters, the dispersion curves for the shielded structure are transformed from dual-mode to single-mode. The structure supports a stop-band characterized by complex modes, which appear as pairs of frequency varying complex conjugate propagation constants. These modes are shown to arise even though the structure is modeled as lossless. In addition to the periodic analysis, the scattering properties of finite cascades of such structures are analyzed and related to the dispersion curves generated from the periodic analysis. Excellent correspondence with full wave finite element method simulations is demonstrated. In conclusion, a physical application is presented: a compact unidirectional ring-slot antenna utilizing the shielded Sievenpiper structure is constructed and tested.

Transients encountered by transformers in power stations during normal operation can have complex oscillatory overvoltages containing a large spectrum of frequency components. These transients can coincide with the natural frequencies of the transformers windings, leading to voltages that can be greater or more severe than the current factory proof tests. This may lead to insulation breakdown and catastrophic failures. Existing lumped parameter RLCG transformer models have been proven to be less accurate for very fast transient overvoltages (VFTO) with frequencies over 1 MHz. A white box model for transient analysis of transformer windings has been developed using Multiconductor Transmission Line (MTL) Theory. This model enables the simulation of natural frequencies of the transformer windings up to frequencies of several MHz, and can be used to compute voltages between turns by representing each turn as a separate transmission line. Both continuous and interleaved disk windings have been modelled and a comparison and validation of the results is presented.
May 2017

Research Doctorate - Doctor of Philosophy (PhD)
This thesis explores electromagnetic wave propagation along single and multi-conductor systems consisting of bare and insulated wires located arbitrarily on either side of interfacing homogeneous half spaces. Equations are derived from first principles to predict the behavior of such systems across the full electromagnetic spectrum. The proposed full spectrum equations extend existing theory to include magnetizable earth and conductors with finite conductivity. They also offer a full spectrum solution for the excitation of conductors located either side of the interfacing half spaces for the first time in published literature. The proposed full spectrum equations are limited to homogeneous earth, and bare and insulated cylindrical conductors but remain general in every other sense. Novel expressions for the continuous modes of the systems have also been developed from these equations. Numerical investigation of the proposed full spectrum equations identifies numerous new discrete modes of propagation for single conductor systems, several with very low attenuation constants that may have industrial application. The modes associated with the full spectrum performance of two conductor systems consisting of parallel conductors located arbitrarily across the interface between the homogeneous half spaces energised by a delta-gap voltage source has been investigated in detail for the first time. Based on the numerical results conditions for which the full spectrum system performance may be approximated by the discrete Transmission Line mode are considered. The proposed full spectrum equations are shown to reduce to the quasi-TEM mode approximations that are Carson and Pollaczek's original solutions to the problem, bringing the understanding of the quasi-TEM mode approximations in line with the full spectrum solutions so that it may be adequately applied to power system safety. The conditions under which this may occur are clearly documented. Alternate quasi-TEM mode approximations are proposed in an analytical form. The assumptions required to reduce these alternate quasi-TEM mode approximations to Carson and Pollaczek's original solutions are detailed, making them, for the first time, a full set of analytical equations that are exact solutions to Carson and Pollaczek's equations. The analytical solutions provide the benefit of improved stability and reduced computation time with respect to numerical calculations.

A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in ful lment of the requirements for the degree of Masters of Science in Engineering (Electrical). Johannesburg, 2016
Power-line communications can be used for the transfer of data across electrical net- works in applications such as automatic meter reading in smart grid technology. As the power-line channel is harsh and plagued with non-Gaussian noise, robust forward error correction schemes are required. This research is a comparative study where a Luby transform code is concatenated with power-line communication systems provided by an up-to-date standard published by electricit e R eseau Distribution France named G3 PLC. Both decoding using Gaussian elimination and belief propagation are imple- mented to investigate and characterise their behaviour through computer simulations in MATLAB. Results show that a bit error rate performance improvement is achiev- able under non worst-case channel conditions using a Gaussian elimination decoder. An adaptive system is thus recommended which decodes using Gaussian elimination and which has the appropriate data rate. The added complexity can be well tolerated especially on the receiver side in automatic meter reading systems due to the network structure being built around a centralised agent which possesses more resources.
MT2017

碩士
國立交通大學
電機與控制工程系
89
It has been known that IC packages have two primary uses. In view of mechanical protection, the IC packages can be used to protect the silicon dies from being damaged or corroded by external substances, such as water, humid air, dust, or even chemicals. For the electric use the conductors in the IC packages are used to transmit signals be-tween the inner die and outer chips. In the past the density of the connectors in the IC packages was not dense and the operation frequency was not as high as hundreds mega hertz. The key considerations of the IC packages were focused on the material problems, such as heat dissipation capability, thermal stresses rather than the electric performance. Nowadays, the size of the IC packages becomes smaller and the operation frequency is demanded up to hundreds mega hertz and even giga hertz. The electric problem of the signal transmission becomes serious. Therefore, the studying the electric performance of the transmission lines in the IC packages becomes important issue. In this thesis, the high dense packaging technology, ball gate array (BGA), is consid-ered as a study target. The linear system theory is employed to analyze the transmis-sion performance of the connectors in BGA. The transmission connectors are trans-ferred to equivalent circuits by using Ansoft SI 4.0. The parameters of the transfer functions of the transmission systems are extracted from the equivalent circuits. The systems are studied by analyzing both the time and frequency responses. Some impor-tant factors of the systems, such as wire lengths, wire widths, bending angles, and dis-tance between wires, which affect the system responses, are studied and analyzed. From many system analyses in this thesis we have concluded several valuable formulae of the transmission lines in IC packages. Those formulae can be used to predict the transmission time and frequency responses and even find the best matching resistance to improve the transmission responses.

This research investigates the realization of parametric amplification in superconducting circuits and structures where nonlinearity is provided by Josephson junction (JJ) elements. We aim to develop a systematic analysis over JJ-based devices toward design of novel traveling-wave Josephson parametric amplifiers (TW-JPA). Chapters of this thesis fall into three categories: lumped JPA, superconducting periodic structures and discrete Josephson transmission lines (DJTL). The unbiased Josephson junction (JJ) is a nonlinear element suitable for parametric amplification through a four-photon process. Two circuit topologies are introduced to capture the unique property of the JJ in order to efficiently mix signal, pump and idler signals for the purpose of signal amplification. Closed-form expressions are derived for gain characteristics, bandwidth determination, noise properties and impedance for this kind of parametric power amplifier. The concept of negative resistance in the gain formulation is observed. A design process is also introduced to find the regimes of operation for gain achievement. Two regimes of operation, oscillation and amplification, are highlighted and distinguished in the result section. Optimization of the circuits to enhance the bandwidth is also carried out. Moving toward TW-JPA, the second part is devoted to modelling the linear wave propagation in a periodic superconducting structure. We derive closed-form equations for dispersion and s-parameters of infinite and finite periodic structures, respectively. Band gap formation is highlighted and its potential applications in the design of passive filters and resonators are discussed. The superconducting structures are fabricated using YBCO and measured, illustrating a good correlation with the numerical results. A novel superconducting Transmission Line (TL), which is periodically loaded by Josephson junctions (JJ) and assisted by open stubs, is proposed as a platform to realize a traveling-wave parametric device. Using the TL model, this structure is modeled by a system of nonlinear partial differential equations (PDE) with a driving source and mixed-boundary conditions at the input and output terminals, respectively. This model successfully emulates parametric and nonlinear microwave propagation when long-wave approximation is applicable. The influence of dispersion to sustain three non-degenerate phased-locked waves through the TL is highlighted. A rigorous and robust Finite Difference Time Domain (FDTD) solver based on the explicit Lax-Wendroff and implicit Crank-Nicolson schemes has been developed to investigate the device responses under various excitations. Linearization of the wave equation, under small-amplitude assumption, dispersion and impedance analysis is performed to explore more aspects of the device for the purpose of efficient design of a traveling-wave parametric amplifier. Knowing all microwave characteristics and identifying different regimes of operation, which include impedance properties, cut-off propagation, dispersive behaviour and shock-wave formation, we exploit perturbation theory accompanied by the method of multiple scale to derive the three nonlinear coupled amplitude equations to describe the parametric interaction. A graphical technique is suggested to find three waves on the dispersion diagram satisfying the phase-matching conditions. Both cases of perfect phase-matching and slight mismatching are addressed in this work. The incorporation of two numerical techniques, spectral method in space and multistep Adams-Bashforth in time domain, is employed to monitor the unilateral gain, superior stability and bandwidth of this structure. Two types of functionality, mixing and amplification, with their requirements are described. These properties make this structure desirable for applications ranging from superconducting optoelectronics to dispersive readout of superconducting qubits where high sensitivity and ultra-low noise operation is required.

Fourth generation (4G) mobile communication systems will need wider band-width channels and improved spectrum efficiency to achieve the specified LTE-advanced 100Mbps (mobile) and 1Gbps (fixed) wireless transmission target rate. The next generation of wireless basestations will also need to be powered from renewable sources, particularly in developing countries. A new generation of components, circuits, algorithms and transmission structures will therefore be required to meet the wider bandwidth and the lower energy requirements. This thesis addresses the transmitter chain, which dominates the basestation power budget. In particular we consider pre-conditioning algorithms for a new generation of high efficiency radio frequency power amplifiers (RFPA).