This work deals with the method for analysis of one-port microstrip circuits which is called as contour-integral method. The general procedure for evaluating of important parameters concerning the analysis of microstrip antennas is given. Next, the geometrical parameters necessary for the calculation of elements in U and H matrices are numerically solved. With the help of these matrices, the input impedance or the reflection coefficient can be easily found.

This thesis describes a study of the measuring methods determining the electrical length of coaxial cable without using a vector network analyzer. First, a general theory of management and its various parameters is briefly discussed. This section is focused more specifically on the coaxial cable and its parameters. The next part is graphically analyzed process considerations in the design of measurement methods and outlined the block structure of the system. The third section describes the working process, prototype testing of the bridge, its measurement and design of the measuring system. In the fourth part the software is described. In conclusion, the results of the work are discussed, accuracy of the measurement system, the obtained parameters chosen with regard to the principle of the measurement system and the overall evaluation of the applicability in practice.

Les filaments composites cœur/peau ont été développés dans le but de proposer des capteurs et de effecteurs textiles pour des applications « smart textiles ». Le filage des filaments a été effectué avec une technique de type extrudeuse à piston. Le travail a porté sur la modification d’une machine de filage par fusion, de la caractérisation de polymères, de la caractérisation des filaments développés et de l’optimisation des techniques d’obtention des filaments. La conception du procédé ainsi que son optimisation ont été effectués avec du PET. La modification de la machine a consisté à concevoir les filières, modifier le piston et à introduire un canal d’alimentation sous forme de tube en inox pour sécuriser le passage du filament métallique d’âme dans le four. Ainsi, 10 filières différentes et trois pistons ont été conçus en se fondant sur les règles industrielles puis leurs performances ont été optimisées. Les polymères ont été caractérisés par DSC, par rhéologie et par techniques analytiques. Ces résultats ont montré la forte influence de la température en particulier une forte réduction de la cristallinité du filament composite. L’optimisation des paramètres d’extrusion a pris en compte la vitesse du piston, la vitesse de bobinage, les modifications de la machine dont le nombre de trous des filières, la position du tube dans la filière, les dimensions internes du tube, le diamètre de sortie de la filière. Il a été montré que la conception de la filière a une influence significative sur la forme des filaments obtenus ainsi que sur la concentricité de l’âme. Les propriétés physiques, morphologiques, tribologiques et mécaniques des filaments ont été mesurés. Ainsi, les filaments ont des diamètres compris entre 350 et 500 µm et peuvent être de formes elliptique, triangulaire, rectangulaire ou circulaire et les meilleures propriétés mécaniques sont obtenues avec les filaments le plus réguliers tandis que les filaments irréguliers présentent un coefficient de frottement plus important. Les résultats concernant la rigidité en flexion se sont avérés peu fiables. A partir des paramètres optimisés, un filament composite de polymère ferroélectrique (PVDF 70%-TrFE 30%) avec une âme cuivre a été filé et a montré de parfaites caractéristiques de forme et de concentricité. Ce filament composite peut maintenant être utilisé pour développer des capteurs et des effecteurs, des transmetteurs de signaux, des boucliers électromagnétiques et de l’électronique intégrable dans les vêtements. / A coaxial composite fiber has been developed for the intended application in textile based sensors, actuators and eletric signal transmissions in wearable textile products. The work focuses on melt extrusion machine modification, characterization of polymers, characterization of developed filaments and optimization techniques for obtaining required results. Melt extrusion machine has been used having piston based mechanism. The process design and optimization was done using polyester polymer. The machine modification includes design of spinnert, piston end modification and introduction of separate feeding channel for core filament in the oven. A number of 10 spinnerets designs were developed according to industrial die design rules and optimized for their performance. The piston end designs developed were 3 in number. A stainless steel tube has been introduced into the oven for a separate secure passage of core filament. The polymer characterization was done by thermal, rheological and analytical techniques. The obtained results exhibited thermal attibutes of the polymer and showed reduction in degree of crystallanity in composite filament. The optimization of extrusion parameters including piston speed, winding speed ; and modifications in machine which includes design parameters of number of holes, tube position, tube internal diameter and spinneret exit diameter were done. It was observed that design parameters have significant effect on cross-sectional shape, eccentricity of core and morphology of filament. The characterization of composite filament has been carried out by physical, morphological, mechanical, tribology and bending techniques. The composite filaments developed were in range of 350-500 µm diameter. The filaments developed have elliptical, triangular, rectangular and circular shapes. The regular filaments showed higher tenacity and breaking strength than irregular shaped filaments. The frictional coefficient values were found higher for irregular shapes. Bending stiffness results obtained were not reliable for irregular cross-sectional shapes. The optimized parameters wers used to develop composite filament using ferroelectric polymer (PVDF-TrFE) having 70 :30 ratio copolymer. The developed filament was very regular in shape with good eccentricity of core. The developed Cu/PVDF-TrFE core/sheath filament can be used for development of sensors and actuators. The Cu/Polyester core/sheath filament can be used for electrical signal transmission lines in wearable electronic textiles and for development of electromagnetic shielding effectiveness fabrics.

Platelet preparations are a source of various autologous growth factors and have numerous applications in tissues engineering. The aim of this work was to development electrospun nanofiber scaffolds with platelet preparations. Scaffolds based on the adhesion of platelets on nanofiber meshes were developed. The scaffolds were able to enhance chondrocyte proliferation in vitro. The main disadvantage of this system is the burst release of growth factors immediately after adhesion. To overcome this, we developed coaxially electrospun scaffolds with incorporated alpha granules. Alpha granules are novel platelet preparations with high amounts of growth factors. This system was able to stimulate chondrocyte proliferation and maintain TGF- 1 concentrations for 7 days. Additionally, a novel drug delivery system with coaxially incorporated liposomes was developed. Liposomes incorporated into nanofibers remain intact and can be used for the delivery of various molecules. The ability to maintain HRP activity was compared to systems based on coaxial electrospinning with liposomes, coaxial electrospinning without liposomes and blend electrospinning. When compared to other systems, coaxial electrospinning with liposomes preserves enzyme activity twice as long. These results clearly indicate the potential of...

Self-assembly is ubiquitous in nature. A diverse range of materials with exceptional properties are accessed from a limited number of sub-units, through controlling structural order on all length-scales. Achieving the same level of control to access functional materials akin to those in nature is a key challenge in chemistry. Self-assembly of block copolymers (BCPs) offers a valuable bottom-up route, governed by non-covalent interactions, to access ordered assemblies on the nanoscale. Anisotropic nanostructures, such as one- and two-dimensional (1D and 2D) micelle morphologies, are of particular interest for various applications including those in biomedicine, catalysis, optoelectronics, and materials engineering. Crystallization-driven self-assembly (CDSA) of BCPs containing a crystallizable core-forming segment presents a robust route to preparing 1D and 2D micelles. Significantly, the use of pre-existing seed micelles in a process termed living CDSA allows access to 1D and 2D nanostructures of controlled size and low size-dispersity. Although CDSA protocols represent powerful tools for the formation controlled 1D and 2D nanostructures, key challenges associated with scale-up of these processes remain. In most cases, increasing the concentration at which living CDSA is performed results in competitive self-nucleation, compromising micelle size-control and dispersity. Living polymerization-induced crystallization-driven self-assembly (PI-CDSA) has been presented as a promising alternative route to accessing scalable 1D micelles. In this case, the polymerization, self-assembly, and seeded growth of a BCP containing a crystallizable core-forming segment occur in situ. However, the scope of living PI-CDSA is currently limited to the use of polyferrocenylsilane (PFS)-based BCPs. Owing to the diverse range of crystalline core chemistries compatible with CDSA protocols, and therefore various promising applications of 1D and 2D micelles, scale-up is essential to facilitate their further investigation and application. The work presented in this thesis focusses on upscaling the preparation and processing of controlled 1D and 2D micelles with a crystalline core. The scalable preparation of low dispersity 2D platelet micelles by living CDSA of a charge-terminated PFS homopolymer with surfactant counteranions is presented in Chapter 2. Here, fundamental insight into the effects of living CDSA concentration on platelet dimensions, structure fidelity, and aggregation behaviour is provided. In Chapter 3, the scope of living PI-CDSA is extended to access scalable length-controlled low dispersity 1D nanofibers containing a biodegradable poly(fluorenetrimethylenecarbonate) (PFTMC) crystalline core. PFTMC-based 1D fibers are of interest for biomedical applications, hence, in this work, it is demonstrated that living PI-CDSA can be used to prepare fibers exhibiting biologically-relevant lengths at scalable concentrations. In Chapter 4, the scalable formation of low dispersity 1D micelles by living CDSA of a PFS-based BCP in a continuous flow setup is explored. Processing of 1D micelles into microfibers using simple, low cost, and high throughput electrospinning techniques is demonstrated in Chapter 5. Finally, Chapter 6 summarises the contribution of this thesis to improving the scalability of CDSA protocols and provides future directions for this work. / Graduate / 2023-04-12

Le sujet de thèse s'inscrit dans le cadre d'un nouveau projet de détermination de la constante de von Klitzing débuté depuis quelques années au LNE et dont l'aboutissement est prévu pour 2018. A ce jour, la mesure la plus exacte de cette constante traçable au Système International d’unités (SI) est obtenue via le raccordement de l'ohm produit par l'effet Hall quantique au farad, matérialisé à l'aide d'un condensateur calculable dit de Thompson-Lampard. Afin d'améliorer sa précédente détermination délivrée en 2000 avec une incertitude relative de 5.10-8,le LNE a décidé de construire un nouvel étalon calculable de Thompson-Lampard (déjà en cours de développement) et d'améliorer l'exactitude de l'ensemble des dispositifs de mesure associés avec pour objectif de réduire l’incertitude globale sur cette détermination à une valeur proche de 10-8. Le travail de thèse porte sur la réalisation, la caractérisation et/ou l’automatisation de la chaîne de mesure associée à cette détermination. / The comparison of electrical quantities expressed in units of the International System of Units (SI) and the same quantities generated from quantum effects is a direct way of determining physical constants. The determination of the von Klitzing constant (quantum of resistance) from a calculable capacitor is a part of this process. The last determination of this constant was conducted at LNE in 2000 with an uncertainty of 5.10-8. To achieve a target uncertainty of 1.10-8, the LNE decided to build a new standard capacitor and improve the associated measurement chain. The work presented here is implemented in the framework of the design/amelioration and the characterization of the measurement chain leading to the relative uncertainty of 1.10-8. Exploratory studies were also conducted about the possible partial or full automation of elements of the measurement chain.

With an increasing demand for rapid high-capacity internet, the telecommunication industry is constantly driven to explore and develop new technologies to ensure stable and reliable networks. To provide a competitive internet service in this growing market, proactive detection and prevention of disturbances are key elements for an operator. Therefore, analyzing network traffic for forecasting disturbances is a well-researched area. This study explores the advantages and drawbacks of implementing a long short-term memory model for forecasting codeword errors in a hybrid fiber-coaxial network. Also, the impact of using multivariate and univariate data for training the model is explored. The performance of the long short-term memory model is compared with a multilayer perceptron model. Analysis of the results shows that the long short-term model, in the vast majority of the tests, performs better than the multilayer perceptron model. This result aligns with the hypothesis, that the long short-term memory model’s ability to handle sequential data would be superior to the multilayer perceptron. However, the difference in performance between the models varies significantly based on the characteristics of the used data set. On the set with heavy fluctuations in the sequential data, the long short-term memory model performs on average 44% better. When training the models on data sets with longer sequences of similar values and with less volatile fluctuations, the results are much more alike. The long short-term model still achieves a lower error on most tests, but the difference is never larger than 7%. If a low error is the sole criterion, the long short-term model is the overall superior model. However, in a production environment, factors such as data storage capacity and model complexity should be taken into consideration. When training the models on multivariate and univariate datasets, the results are unambiguous. When training on all three features, ratios of uncorrectable and correctable codewords, and signal-to-noise ratio, the models always perform better. That is, compared to using uncorrectable codewords as the only training data. This aligns with the hypothesis, which is based on the know-how of hybrid fiber-coaxial experts, that correctable codewords and signal-to-noise ratio have an impact on the occurrence of uncorrectable codewords. / På grund av den ökade efterfrågan av högkvalitativt internet, så drivs telekomindustrin till att konsekvent utforska och utveckla nya teknologier som kan säkerställa stabila och pålitliga nätverk. För att kunna erbjuda konkurrenskraftiga internettjänster, måste operatörerna kunna förutse och förhindra störningar i nätverken. Därför är forskningen kring hur man analyserar och förutser störningar i ett nätverk ett väl exploaterat område. Denna studie undersökte för- och nackdelar med att använda en long short-term memory (LSTM) för att förutse kodordsfel i ett hybridfiber-koaxialt nätverk. Utöver detta undersöktes även hur multidimensionell träningsdata påverkade prestandan. I jämförelsesyfte användes en multilayer perceptron (MLP) och dess resultat. Analysen av resultaten visade att LSTM-modellen presterade bättre än MLP-modellen i majoriteten av de utförda testerna. Men skillnaden i prestanda varierade kraftigt, beroende på vilken datauppsättning som användes vid träning och testning av modellerna. Slutsatsen av detta är att i denna studie så är LSTM den bästa modellen, men att det inte går att säga att LSTM presterar bättre på en godtycklig datauppsättning. Båda modellerna presterade bättre när de tränades på multidimensionell data. Vidare forskning krävs för att kunna determinera om LSTM är den mest självklara modellen för att förutse kodordsfel i ett hybridfiber-koaxialt nätverk.

[ES] La energía geotérmica de baja entalpía es una alternativa eficiente y renovable a los sistemas convencionales para proporcionar calefacción, refrigeración y producir agua caliente sanitaria (ACS) de forma sostenible. El proyecto GEOTeCH plantea el desarrollo de sistemas con bomba de calor geotérmica más eficientes y con un coste menor en comparación con el mercado. Para ello, se ha desarrollado un nuevo tipo de intercambiador enterrado coaxial con flujo helicoidal en el tubo externo que presenta una mayor eficiencia y permite reducir la longitud de intercambiador a instalar, así como una bomba de calor dual con compresor de velocidad variable, capaz de trabajar con el terreno o el aire como fuente/sumidero, seleccionando la que proporcione un mejor rendimiento del sistema. El principal objetivo es desarrollar un sistema eficiente y replicable para proporcionar calefacción, refrigeración y producir ACS en el sector de mercado de pequeños edificios con un tamaño menor en el campo de intercambiadores enterrados y un aumento de la eficiencia. Para demostrar la aplicabilidad de estos sistemas, se han construido tres instalaciones demostración en tres países europeos. En esta tesis doctoral se ha desarrollado un modelo dinámico completo del sistema en el software TRNSYS, capaz de reproducir el comportamiento de los diferentes componentes y del sistema en general. Este modelo constituye una herramienta útil para el desarrollo y análisis de diferentes estrategias de control sin la necesidad de implementarlas en instalaciones reales, así como analizar el comportamiento del sistema funcionando bajo condiciones diferentes. Para este propósito, es necesario desarrollar modelos detallados de los nuevos componentes desarrollados en el proyecto: el intercambiador enterrado coaxial helicoidal y la bomba de calor dual; para poder acoplarlos al resto de componentes en el modelo completo del sistema. Por ello, se ha desarrollado un modelo dinámico del nuevo intercambiador, capaz de reproducir con precisión el comportamiento a corto plazo del intercambiador, enfocado a la evolución de la temperatura del fluido, y se ha validado con datos experimentales en diferentes condiciones de operación. Para poder reproducir no solo el comportamiento dinámico del intercambiador enterrado, sino también la respuesta a largo plazo del terreno y la interacción entre intercambiadores en un campo, se ha desarrollado otro modelo en TRNSYS que realiza esta función. De esta manera, al acoplar ambos modelos es posible reproducir el comportamiento a corto plazo del intercambiador enterrado a la vez que la respuesta a largo plazo del terreno. Por otro lado, se ha implementado en TRNSYS un modelo de la bomba de calor dual desarrollado. Con este modelo es posible calcular la capacidad de la bomba de calor dependiendo del modo de operación en que esté funcionando, de la frecuencia del compresor y otras variables y condiciones de operación. El modelo del sistema dual en TRNSYS se ha utilizado para hacer un análisis de su comportamiento funcionando en diferentes climas, para ello se han seleccionado tres ciudades en España y en Europa con diferentes climas y se han realizado simulaciones del sistema funcionando en cada ciudad. Por otro lado, también se ha modelado en TRNSYS una de las instalaciones demostración del proyecto GEOTeCH, incluyendo el edificio climatizado y el acoplamiento con los fan coils. Con este modelo se estudia una nueva estrategia para controlar la frecuencia del compresor en base a la temperatura de las habitaciones, en lugar de controlarla en base a la temperatura de suministro, con el objetivo de reducir el consumo del compresor cuando ya se haya conseguido el confort. Además, otras estrategias de optimización se han analizado con el modelo.Por tanto, los modelos desarrollados constituyen herramientas útiles para ayudar en el diseño del sistema y los diferentes componentes, el análisis de su comportamiento y el d / [CA] L'energia geotèrmica de baixa entalpia es planteja com una alternativa eficient i renovable als sistemes convencionals per proporcionar calefacció, refrigeració i produir aigua calenta sanitària (ACS) de forma sostenible. El projecte GEOTeCH planteja el desenvolupament de sistemes amb bomba de calor geotèrmica més eficients i amb un cost menor en comparació amb el mercat. Per a això, s'ha desenvolupat un nou tipus d'intercanviador enterrat coaxial amb flux helicoïdal en el tub extern que presenta una major eficiència i permet reduir la longitud a instal·lar, així com una bomba de calor dual amb compressor de velocitat variable, capaç de treballar amb el terreny o l'aire com a font, seleccionant la que proporcione un millor rendiment. Aquests components s'utilitzen en el nou sistema amb bomba de calor dual. El principal objectiu és desenvolupar un sistema eficient i replicable per proporcionar calefacció, refrigeració i produir ACS en edificis xicotets amb una grandària menor d'intercanviadors soterrats i un augment de l'eficiència. Per demostrar l'aplicabilitat d'aquests sistemes, s'han construït tres instal·lacions demostració en Itàlia, Països Baixos i Regne Unit. En aquesta tesi s'ha desenvolupat un model dinàmic complet del sistema en TRNSYS, capaç de reproduir el comportament dels components i del sistema en general. Aquest model constitueix una eina útil per al desenvolupament i anàlisi de diferents estratègies de control sense la necessitat d'implementar-les en instal·lacions reals, així com analitzar el comportament del sistema funcionant en condicions diferents. Per a això, cal desenvolupar models detallats dels nous components desenvolupats en el projecte: l'intercanviador enterrat i la bomba de calor dual; per poder acoblar-los a la resta de components. Per això, s'ha desenvolupat un model dinàmic del nou intercanviador enterrat, capaç de reproduir amb precisió el comportament a curt termini de l'intercanviador, enfocat a l'evolució de la temperatura del fluid, i s'ha validat amb dades experimentals en diferents condicions d'operació. Per a poder reproduir no només el comportament dinàmic de l'intercanviador soterrat, sinó també la resposta a llarg termini del terreny i la interacció entre intercanviadors en un camp, s'ha desenvolupat un altre model en TRNSYS que realitza aquesta funció. D'aquesta manera, en acoblar els dos models és possible reproduir el comportament a curt termini de l'intercanviador enterrat, al mateix temps que la resposta a llarg termini del terreny. D'altra banda, s'ha implementat en TRNSYS un model de la bomba de calor. Amb aquest model és possible calcular la capacitat de la bomba de calor depenent del mode d'operació en què estiga funcionant, de la freqüència del compressor i altres variables i condicions d'operació. El model del sistema dual en TRNSYS s'ha utilitzat per a fer una anàlisi del seu comportament funcionant en diferents climes, per a això s'han seleccionat tres ciutats a Espanya i tres a Europa amb diferents climes i s'han realitzat simulacions del sistema funcionant en cada ciutat durant un any. S'ha analitzat l'eficiència del sistema en cada ciutat, així com l'ús de cadascuna de les fonts (aire / terreny). D'altra banda, també s'ha modelat en TRNSYS una de les instal·lacions demostració del projecte GEOTeCH, incloent l'edifici d'oficines climatitzat i l'acoblament amb els fan coils. Amb aquest model es pretén estudiar una nova estratègia per a controlar la freqüència del compressor d'acord amb la temperatura de les habitacions, en lloc de controlar-la en base a la temperatura de subministrament, amb l'objectiu de reduir el consum del compressor quan les habitacions ja es troben en condicions de confort. A més, altres estratègies d'optimització s'han analitzat amb el model. Per tant, els models desenvolupats constitueixen eines útils per ajudar en el disseny del sistema i els diferents components, l'anàlisi del / [EN] Low enthalpy geothermal energy is considered as an efficient and renewable alternative to conventional systems to provide heating, cooling and Domestic Hot Water (DHW) production in a sustainable way. In this context, the GEOTeCH project proposes the development of more efficient geothermal heat pump systems with a lower cost compared to the market. To this end, a new type of coaxial Borehole Heat Exchanger (BHE) with helical flow through the outer tube has been developed, which presents a higher efficiency and allows to reduce the length of the heat exchanger to be installed, as well as a Dual Source Heat Pump (DSHP) with variable speed compressor, capable of working with the ground or air as a source / sink, selecting the one that provides the best performance of the system. These components are used in the new DSHP system developed. The main objective is to develop efficient and replicable systems to provide heating, cooling and DHW in the market sector of small buildings with a smaller size of the BHE field and an increase in the efficiency. To demonstrate the applicability of these systems, three demonstration facilities have been installed in Italy, the Netherlands and the UK. In this thesis, a complete dynamic model of the system has been developed in the TRNSYS software, capable of reproducing the behavior of the different components and the system in general. This model is a useful tool for the development and analysis of different control strategies without the need to implement them in real installations, as well as analyses the behavior of the system operating under different conditions. For this purpose, it is necessary to develop detailed models of the new components developed in the project: the BHE and the DSHP; to couple them to the rest of the components of the system. For this reason, a dynamic model of the new BHE was developed, able to accurately reproduce its short-term behavior, focused on the evolution of the fluid temperature, and validated with experimental data in different operating conditions. In order to reproduce not only the dynamic behavior of the BHE, but also the long-term response of the ground and the interaction between BHEs in a field, another model was developed in TRNSYS. In this way, by coupling both models, it is possible to reproduce the short-term behavior of the BHE as well as the long-term response of the ground. On the other hand, a model of the DSHP was implemented in TRNSYS. With this model, it is possible to calculate the capacity of the heat pump depending on the operating mode in which it is operating, the frequency of the compressor and other variables and operating conditions. The model of the hybrid system in TRNSYS has been used to make an analysis of its behavior working in different climatic conditions, for which three cities have been selected in Spain and three in Europe, with different climates. So, different simulations of the system have been carried out in each city for one year. The efficiency of the system in each city has been analyzed, as well as the use of each of the sources (air / ground). On the other hand, one of the demo-sites of the GEOTeCH project, including the conditioned office building and the coupling with the fan coils, has also been modelled in TRNSYS. With this model, it is studied a new strategy to control the frequency of the compressor based on the temperature of the rooms, instead of controlling it based on the supply temperature, with the aim of reducing the consumption of the compressor when the rooms are already in comfort conditions. In addition, other optimization strategies have been analyzed with the model. Therefore, the models developed, both for the BHE and the system, are able to reproduce their operation and can be used as virtual installations, constituting useful tools to help in the design of the system and the different components, the analysis of their behavior and the development of optimization strategies. / I would like to acknowledge the financial support that has made this PhD thesis possible. The present work has been supported by the European Community Horizon 2020 Program for European Research and Technological Development (2014-2020) inside the framework of the project 656889 – GEOTeCH (Geothermal Technology for Economic Cooling and Heating), also by the Generalitat Valenciana inside the program “Ayudas para la contratación de personal investigador en formación de carácter predoctoral (ACIF/2016/131)” and by the Institute for Energy Engineering of the Universitat Politècnica de València. / Cazorla Marín, A. (2019). MODELLING AND EXPERIMENTAL VALIDATION OF AN INNOVATIVE COAXIAL HELICAL BOREHOLE HEAT EXCHANGER FOR A DUAL SOURCE HEAT PUMP SYSTEM [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/125696 / TESIS

An electrical bushing is one of the most important elements in a power transformer. Steep front surges such as transient impulse voltage from lightning strikes is an inevitable electromagnetic transient mostly happening in power transmission and distribution system. The bushing might lead to be degraded due to such kind of surge. This project deals with overvoltage stress distribution on the transformer bushing under the effect of electromagnetic transient response such as lightning impulse.  To understand the behavior of transient response on the bushing, a proper model of power transformer bushing is built-in Comsol multiphysics to authenticate the stress distribution. The electromagnetic wave of impulse propagates onto the overhead line that connects with the transformer. Some understanding of the transient behavior of a conductor bushing has been achieved through studying the influence of inductance property and the skin effect characteristics of a multi-layer coaxial cable on the wave propagation, which has been structured in this project to simplify the model. On the other hand, the skin effect analysis on the conductor of the bushing has been taken also into account in this project using real conductor simulation in the Comsol model. Thus, it will be interesting to compare the real conductor model with the perfect conductor of the bushing through analyzing the current density effect on it.  In this project, multi-layer of coaxial cable and transformer bushing are simulated. The simulation is carried out for time domain and frequency domain in Comsol based on the model characteristics. / En elektrisk genomföring är ett av de viktigaste elementen i en transformator. Spänningsvågor med branta fronter som impulsspänningar från blixtnedslag är ett oundvikligt elektromagnetiskt övergående fenomen som oftast sker i kraftöverförings- och distributionssystem. Genomföringen kan leda till att degraderas på grund av en sådan våg. Detta projekt handlar om fördelning av överspännings på transformatorgenomföringen under påverkan av elektromagnetisk transient respons, såsom blixtimpuls.  För att förstå beteendet hos övergående respons på genomföringen är en korrekt modell av transformatorgenomföring inbyggd Comsol-flerfysik för att autentisera spänningsfördelningen. Den elektromagnetiska impulsvågen fortplantas från luftledningen som ansluter till transformatorn. Viss förståelse för det övergående beteendet hos en ledargenomföring har uppnåtts genom att studera påverkan av induktansegenskaper och hudeffektegenskaperna hos en flerskikts koaxialkabel på vågutbredningen, vilket har strukturerats i detta projekt för att förenkla modellen. Å andra sidan har hudeffektanalysen på genomföringens ledare beaktats i detta projekt med användning av verklig ledarsimulering i Comsol-modellen. Således blir det intressant att jämföra den riktiga ledarmodellen med den perfekta ledaren för genomföringen genom att analysera strömtäthetseffekten på den.  I detta projekt simuleras flerskikt av koaxialkabel och transformatorgenomföring. Simuleringen utförs för tidsdomän och frekvensdomän i Comsol baserat på modellegenskaperna.

There are more connected wireless devices than everbefore and with the rise of new smart systems such as self-drivingcars and smart cities new antenna solutions for transmittingsignals are needed. One important part of these systems is thefilters which filter out all the unwanted signals. In this report,we present a solution for manufacturing such a filter with apassband from 26-29 GHz and a stopband from 29-60 GHz usinga fully metallic glide-symmetric structure. Ideas of combiningmultiple unit cell designs to achieve wider stopbands and higherattenuation are explored using dispersion engineering wherethe advantages and the disadvantages of using this method arepresented. Furthermore, ways of combining the filter to standardconnections using a coaxial cable to waveguide transition areproposed and designed. The usage of multiple unit cell designsis proven to be a solution for achieving wider stopbands withminimum coupling between modes. / Det finns fler trådlösa enheter uppkoppladeän n°agonsin tidigare och med ökningen av nya smarta systemsom självkörande bilar och smarta städer finns ett behov av nyaantennlösningar för överföring av information. En viktig del avdessa system är filtren som filtrerar bort alla oönskade signaler.I denna rapport presenterar vi en lösning för att konstrueraett sådant filter med ett passband från 26-29 GHz och ettstoppband från 29-60 GHz med en helt metallisk glidsymmetriskstruktur. Id´eer att kombinera flera enhetscellsdesigner för attuppnå bredare stoppband och högre attenuering undersöks medhjälp av dispersionsteknik, där fördelarna och nackdelarna medatt använda denna metod presenteras. Dessutom föreslås ochutformas sätt att kombinera filtret till standardanslutningar meden koaxialkabel till vågledarövergång. Användningen av fleraenhetscell designer visar sig vara en lösning för att skapa bredastoppband med minimal koppling mellan ”modes”. / Kandidatexjobb i elektroteknik 2021, KTH, Stockholm