One of the challenges of the mobile industry is to cope with the growth of mobile traffic demand expected for the next years, primarily driven by the increasing usage of mobile video services. Indeed, the existence of increasingly powerful terminals is encouraging the consumption of high-quality video content. Usually, video services are identified with linear Television (TV) and scheduled broadcast (point-to-multipoint (p-t-m)) distribution. However, the consumption of video content over mobile networks is different from traditional fixed TV because contents are mainly consumed on-demand with unicast point-to-point (p-t-p) connections. Then, the convergence of linear TV and on-demand content delivery represents a challenge that requires a combined broadcast/unicast transmission model. This dissertation addresses the use of broadcasting technologies for the provision of mobile multimedia services in Fourth Generation (4G) mobile broadband networks and beyond. Specifically, the dissertation focuses on the broadcast technology included in 4G Long Term Evolution (LTE) and LTE Advanced (LTE-A) networks, known as Enhanced Multicast Broadcast Multimedia Services (eMBMS). It analyses the benefits of the eMBMS physical layer aspects regarding Multimedia Broadcast Multicast Services over a Single Frequency Network (MBSFN) deployments and identifies the current limitations of eMBMS at physical layer by comparing with the broadcast technology of the other 4G mobile system, the Institute of Electrical and Electronics Engineers (IEEE) 802.16m standard. Those limitations are the use of a dedicated carrier and Multiple-Input Multiple-Output (MIMO) techniques for broadcast transmissions. Our investigations employ a complete simulation platform including link-level and system-level simulations to evaluate the performance of broadcast transmissions in these real technologies. The research on eMBMS services is aimed at finding the optimum delivery of streaming and file download services focusing on the Radio Resource Management (RRM) problem and trade-off between Physical layer – Forward Error Correction (PHY-FEC) and Application Layer - Forward Error Correction (AL-FEC). Concerning streaming services, results show that the use of AL-FEC increases the coverage level and, then, the maximum service data rate. The gain due to AL-FEC is greater in scenarios with high mobility users, although, this gain is limited if low zapping times are desired. Regarding file delivery services, this dissertation analyses the duration of the transmission required to guarantee the correct file reception and the reduction in the mean throughput of unicast users with different delivery modes. They are the unicast delivery, the eMBMS delivery and a hybrid approach, which combines a first eMBMS delivery with a postdelivery error repair phase with unicast transmissions. Our results show that the hybrid delivery is the most efficient configuration in terms of file download time, although it further reduces unicast performance. / Calabuig Gaspar, J. (2015). Broadcasting in 4G mobile broadband networks and its evolution towards 5G [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48561

Yes / Much attention has been paid to making 5G developments more en-ergy efficient, especially in view of the need for using high data rates with more complex modulation schemes within a limited bandwidth. The concept of the Doherty power amplifier for improving amplifier efficiency is explained in addi-tion to a case study of a 70W asymmetrical Doherty power Amplifier using two GaN HEMTs transistors with peak power ratings of 45W and 25W. The rationale for this choice of power ratio is discussed. The designed circuit works in the 3.4GHz frequency band with 200 MHz bandwidth. Rogers RO4350B substrate with dielectric constant εr=4.66 and thickness 0.035 mm is used. The perfor-mance analysis of the Doherty power amplifier is simulated using AWR MWO software. The simulated results showed that 54-64% drain efficiency has been achieved at 8 dB back-off within the specified bandwidth with an average gain of 10.7 dB.

[ES] La tecnologia en fases de paquets es va convertir en dècades enrere en la indústria del radar. Avui en dia, la matriu de fases o la formació de bigues s'està convertint en una necessitat per a la comunicació digital. L'explotació d'un sistema de transmissió de feixos ajudarà a reduir el consum total d'energia de les estacions base i dels equips d'usuaris. També permetrà al servei oferir dades molt més elevades i millorar la qualitat del servei. La investigació sobre la comunicació digital i la comunicació requereix una antena i un maquinari compatible. El maquinari hauria de ser capaç de gestionar diferents escenaris i enfocaments per a problemes de comunicació mòbil. Hi ha diversos sistemes utilitzats per a la investigació de la formació de bigues, especialment per a la comunicació mòbil. Aquests sistemes pateixen de diverses deficiències. Són cares d'implementar, no adaptatives i fixades a una arquitectura relacionada amb determinat algorisme de generació de feixos o amb un nombre d'elements d'array fix. En aquesta tesi es proposa un nou sistema de matrius per fases. Aquest sistema es podria explotar per a la investigació en problemes de comunicació mòbil o radar. Està compost per una xarxa d'antenes planes de 8x1, canals de conversió de RF a banda base i processador de banda base. Es fa una estimació de la transformació de fases i de la DOA en mostres digitals de banda base. Això proporciona al sistema dinàmica quant als algorismes provats. Amb aquesta finalitat, es fan servir juntes SDR àgils per adquirir senyals de la matriu d'antenes i convertir-les en fluxos de dades digitals. Els fluxos de dades es processen després en un processador de banda base basat en FPGA. A més de ser baixos en costos i assequibles per part de petits instituts d'investigació i investigacions independents, el sistema es pot ajustar per portar més elements de matriu d'antenes. La matriu monopola plana de 8x1 està dissenyada, simulada i mesurada. Es combinen i descriuen les característiques d'impedància i de radiació. Els SDR s'introdueixen i es calibren per al funcionament de diversos elements i s'introdueixen els mètodes de calibratge per incerteses de fase i amplitud. El rendiment global del sistema es prova mitjançant diferents algorismes de formulació de feixos i algorismes de direcció d'estimació d'arribada. Els resultats de la mesura mostren que el sistema és fiable. S'aconsegueix un model de beamformació amb bona resolució i un rebuig elevat de la interferència. La estimació de la direcció d'arribada és precisa. / [CA] La tecnología de matriz en fase hizo una rotación en la industria del radar hace décadas. Hoy en día, la matriz en fase, o formación de haz, se está convirtiendo en una necesidad para la comunicación digital. La explotación de la formación de haz ayudaría a reducir el consumo de energía general de las estaciones base y el equipo del usuario. También permitirá que el servicio brinde datos mucho más altos y mejore la calidad del servicio. La investigación sobre la formación y comunicación de haces digitales requiere un conjunto de antenas y hardware compatible. El hardware debe ser capaz de manejar diferentes escenarios y enfoques para problemas de comunicación móvil. Hay varios sistemas utilizados para la investigación de conformación de haz, especialmente para la comunicación móvil. Estos sistemas sufren de varias deficiencias. Son costosos de implementar, no adaptativos y fijos a una arquitectura relacionada con cierto algoritmo de conformación de haz o con un número de elementos de arreglo fijo. En esta tesis, se propone un nuevo sistema matricial por fases. Este sistema podría ser explotado para la investigación en comunicaciones móviles o problemas de radar. Está compuesto por un conjunto de antenas planas de 8x1, canales de conversión de RF a banda base y procesador de banda base. La formación de haz y la estimación de DOA se realizan en muestras digitales de banda base. Esto proporciona al sistema dinamismo con respecto a los algoritmos probados. Para ese propósito, las tarjetas SDR ágiles se utilizan para adquirir señales de la red de antenas y convertirlas en flujos de datos digitales. Los flujos de datos se procesan en un procesador de banda base basado en FPGA. Además de ser de bajo costo y asequible para los pequeños institutos de investigación e investigaciones independientes, el sistema se puede ajustar para llevar más elementos de la red de antenas. El conjunto monopolo plano 8x1 está diseñado, simulado y medido. La correspondencia de impedancia y las características de radiación se representan y describen. Los SDR se introducen y se calibran para la operación de elementos múltiples y se introducen los métodos de calibración para las incertidumbres de fase y amplitud. El rendimiento general del sistema se prueba mediante diferentes algoritmos de conformación de haz y algoritmos de estimación de la dirección de llegada. Los resultados de las mediciones muestran que el sistema es confiable. Se logra una conformación de haz con buena resolución y alto rechazo de interferencia. Dirección de estimación de la llegada es precisa. / [EN] Phased array technology made a turnover in radar industry decades ago. Nowadays, phased array, or beamforming, is becoming a necessity for digital communication. Exploiting beamforming would help in reducing the overall power consumption of base stations and user equipment. It will also enables the service to provide much higher datarates and enhance the quality of service. Research on digital beamforming and communication requires antenna array and compatible hardware. The hardware should be capable of handling different scenarios and approaches for mobile communication problems. There are several systems used for beamforming research especially for mobile communication. These systems suffer from several deficiencies. They are either expensive to implement, not adaptive and fixed to an architecture related to certain beamforming algorithm or with fixed array elements number. In this thesis, a new phased array system is proposed. This system could be exploited for research in mobile communication or radar problems. It is composed of 8x1 planar antenna array, RF to baseband conversion channels and base band processor. Beamforming and DOA estimation is done on base band digital samples. This provides the system with dynamicity regarding tested algorithms. For that purpose, agile SDR boards are used to acquire signals from antenna array and convert them to digital data streams. Data streams are then processed in an FPGA based base band processor. In addition to being low in cost and affordable by small research institutes and freelancing researches, the system can be adjusted to carry more antenna array elements. The 8x1 planar monopole array is designed, simulated and measured. Impedance matching and radiation characteristics are plotted and described. SDRs are introduced and calibrated for multi-element operation and calibration method for phase and amplitude uncertainties are introduced. Overall system performance is tested by different beamforming algorithms and direction of arrival estimation algorithms. Measurement results show that the system is reliable. Beamforming with good resolution and high interference rejection is achieved. Direction of arrival estimation is accurate. / Haroun, MH. (2019). 8×1 Antenna Array System for Uplink Beamforming in LTE-A and 5G NR [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/129852

Le réseau mobile d’Orange France comprend plus de 100 000 antennes 2G, 3G et 4G sur plusieurs bandes de fréquences sans compter les nombreuses femto-cells fournies aux clients pour résoudre les problèmes de couverture. Ces chiffres ne feront que s’accroître pour répondre à la demande sans cesse croissante des clients pour les données mobiles. Cela illustre le défi énorme que rencontrent les opérateurs de téléphonie mobile en général à savoir gérer un réseau aussi complexe tout en limitant les coûts d’opération pour rester compétitifs. Cette thèse s’attache à utiliser le concept SON (réseaux auto-organisants) pour réduire cette complexité en automatisant les tâches répétitives ou complexes. Plus spécifiquement, nous proposons des algorithmes d’optimisation automatique pour des scénarios liés à la densification par les small cells ou les antennes actives. Nous abordons les problèmes classiques d’équilibrage de charge mais avec un lien backhaul à capacité limitée et de coordination d’interférence que ce soit dans le domaine temporel (notamment avec le eICIC) ou le domaine fréquentiel. Nous proposons aussi des algorithmes d’activation optimale de certaines fonctionnalités lorsque cette activation n’est pas toujours bénéfique. Pour la formulation mathématique et la résolution de tous ces algorithmes, nous nous appuyons sur les résultats de l’approximation stochastique et de l’optimisation convexe. Nous proposons aussi une méthodologie systématique pour la coordination de multiples fonctionnalités SON qui seraient exécutées en parallèle. Cette méthodologie est basée sur les jeux concaves et l’optimisation convexe avec comme contraintes des inégalités matricielles linéaires. / The mobile network of Orange in France comprises more than 100 000 2G, 3G and 4G antennas with severalfrequency bands, not to mention many femto-cells for deep-indoor coverage. These numbers will continue toincrease in order to address the customers’ exponentially increasing need for mobile data. This is an illustrationof the challenge faced by the mobile operators for operating such a complex network with low OperationalExpenditures (OPEX) in order to stay competitive. This thesis is about leveraging the Self-Organizing Network(SON) concept to reduce this complexity by automating repetitive or complex tasks. We specifically proposeautomatic optimization algorithms for scenarios related to network densification using either small cells orActive Antenna Systems (AASs) used for Vertical Sectorization (VeSn), Virtual Sectorization (ViSn) and multilevelbeamforming. Problems such as load balancing with limited-capacity backhaul and interference coordination eitherin time-domain (eICIC) or in frequency-domain are tackled. We also propose optimal activation algorithms forVeSn and ViSn when their activation is not always beneficial. We make use of results from stochastic approximationand convex optimization for the mathematical formulation of the problems and their solutions. We also proposea generic methodology for the coordination of multiple SON algorithms running in parallel using results fromconcave game theory and Linear Matrix Inequality (LMI)-constrained optimization.

The next generation wireless networks i.e. 5G aim to provide multi-Gbps data traffic, in order to satisfy the increasing demand for high-definition video, among other high data rate services, as well as the exponential growth in mobile subscribers. To achieve this dramatic increase in data rates, current research is focused on improving the capacity of current 4G network standards, based on Long Term Evolution (LTE), before radical changes are exploited which could include acquiring additional/new spectrum. The LTE network has a reuse factor of one; hence neighbouring cells/sectors use the same spectrum, therefore making the cell edge users vulnerable to inter-cell interference. In addition, wireless transmission is commonly hindered by fading and pathloss. In this direction, this thesis focuses on improving the performance of cell edge users in LTE and LTE-Advanced (LTE-A) networks by initially implementing a new Coordinated Multi-Point (CoMP) algorithm to mitigate cell edge user interference. Subsequently Device-to-Device (D2D) communication is investigated as the enabling technology for maximising Resource Block (RB) utilisation in current 4G and emerging 5G networks. It is demonstrated that the application, as an extension to the above, of novel power control algorithms, to reduce the required D2D TX power, and multihop transmission for relaying D2D traffic, can further enhance network performance. To be able to develop the aforementioned technologies and evaluate the performance of new algorithms in emerging network scenarios, a beyond-the-state-of-the-art LTE system-level simulator (SLS) was implemented. The new simulator includes Multiple-Input Multiple-Output (MIMO) antenna functionalities, comprehensive channel models (such as Wireless World initiative New Radio II i.e. WINNER II) and adaptive modulation and coding schemes to accurately emulate the LTE and LTE-A network standards. Additionally, a novel interference modelling scheme using the 'wrap around' technique was proposed and implemented that maintained the topology of flat surfaced maps, allowing for use with cell planning tools while obtaining accurate and timely results in the SLS compared to the few existing platforms. For the proposed CoMP algorithm, the adaptive beamforming technique was employed to reduce interference on the cell edge UEs by applying Coordinated Scheduling (CoSH) between cooperating cells. Simulation results show up to 2-fold improvement in terms of throughput, and also shows SINR gain for the cell edge UEs in the cooperating cells. Furthermore, D2D communication underlaying the LTE network (and future generation of wireless networks) was investigated. The technology exploits the proximity of users in a network to achieve higher data rates with maximum RB utilisation (as the technology reuses the cellular RB simultaneously), while taking some load off the Evolved Node B (eNB) i.e. by direct communication between User Equipment (UE). Simulation results show that the proximity and transmission power of D2D transmission yields high performance gains for a D2D receiver, which was demonstrated to be better than that of cellular UEs with better channel conditions or in close proximity to the eNB in the network. The impact of interference from the simultaneous transmission however impedes the achievable data rates of cellular UEs in the network, especially at the cell edge. Thus, a power control algorithm was proposed to mitigate the impact of interference in the hybrid network (network consisting of both cellular and D2D UEs). It was implemented by setting a minimum SINR threshold so that the cellular UEs achieve a minimum performance, and equally a maximum SINR threshold to establish fairness for the D2D transmission as well. Simulation results show an increase in the cell edge throughput and notable improvement in the overall SINR distribution of UEs in the hybrid network. Additionally, multihop transmission for D2D UEs was investigated in the hybrid network: traditionally, the scheme is implemented to relay cellular traffic in a homogenous network. Contrary to most current studies where D2D UEs are employed to relay cellular traffic, the use of idle nodes to relay D2D traffic was implemented uniquely in this thesis. Simulation results show improvement in D2D receiver throughput with multihop transmission, which was significantly better than that of the same UEs performance with equivalent distance between the D2D pair when using single hop transmission.

La demande de transmissions à débits de plus en plus élevés s’accentue davantage avec l’essor de nouveaux services dans les réseaux de communication sans fils. Pour répondre à cette demande, une solution consiste à augmenter la capacité de transmission du canal radiofréquence entre la station de base et le terminal portatif. Ceci peut être réalisé en augmentant le nombre d’éléments rayonnant impliqués à l’émission et à la réception de cette liaison radiofréquence : on parle alors de technique MIMO (Multiple Input, Multiple Output). Cette thèse porte principalement sur la conception, l’optimisation et la caractérisation de systèmes multi-antennaires pour techniques de diversité et MIMO en bandes LTE (Long Term Evolution). Trois prototypes multi-bandes sont proposés dont deux systèmes planaires et un système d’antennes IFAs compactes. De nouvelles solutions multi-bandes et l’influence de la position de l’antenne sur le plan de masse sont étudiées pour réaliser de la diversité spatiale, de polarisation et de diagramme de rayonnement avec une faible corrélation entre les signaux reçus sur chaque antenne mais surtout une bonne efficacité totale. Une ligne de neutralisation est utilisée pour isoler les antennes et un fonctionnement multi-bande est réalisé. L’impédance d’entrée des antennes est étudiée avec la méthode de Youla & Carlin afin d’améliorer la bande passante de la structure compacte de type IFA. Les performances en diversité et en MIMO de ces systèmes sont évaluées dans différents environnements de propagation. Elles montrent que ces systèmes peuvent être utilisés efficacement pour des applications en diversité et MIMO. / The transmission demand for increasing data rate becomes more and more important with the development of new services in radio communication networks. To answer to this demand, one solution consists in increasing the transmission capacity of the radio channel between the base station and the handset terminal. This can be realized by increasing the number of radiating elements involved in the transmission and the reception of this radio link: we talk about MIMO (Multiple Input Multiple Output) technique. The work realized in this thesis concerns mainly design, optimization and characterization of multi-antenna systems for MIMO and diversity techniques in LTE (Long Term Evolution) bands. Three multi bands prototypes are proposed whose two planar systems and one compact IFAs antennas system. News multiband solution and antenna position influence on the PCB were studied to realize spatial, polarization and pattern diversity with low correlation between received signals on each antenna and a good efficiency. The neutralization line was used for antennas isolation and its application in multiband was realized. The antenna load impedance has been studied with Youla & Carlin method in order to improve the frequency bandwidth of the compact IFA structure. Diversity and MIMO performances of these systems were evaluated in different propagation environments. They show that these systems can be effectively used for diversity and MIMO application.

L’apparition accidentelle d’un arc électrique dans le système de distribution électrique d’un aéronef peut compromettre la sécurité du vol. Il existe peu de travaux liés à cette problématique.Le but de ce travail est donc d’étudier le comportement d’un arc électrique, en conditions aéronautiques,par des approches théorique, numérique, et expérimentale. Dans ce travail, un modèle MHD de la colonne d’arc à l’ETL a été utilisé, et résolu à l’aide du logiciel commercial comsolMultiphysics. Afin de décrire l’interaction plasma-électrodes, le modèle a dû étendu pour inclure les écarts à l’équilibre près des électrodes. Ces zones ont été prises en compte en considérant la conservation du courant et de l’énergie dans la zone hors-équilibre. L’approche choisie et le développement du modèle ont été détaillés. La validation du modèle dans le cas d’un arc libre a montré un excellent accord avec les résultats numériques et expérimentaux de la littérature.Ce modèle d’arc libre a été étendu au cas de l’arc se propageant entre des électrodes en configuration rails et en géométrie 3D. Une description auto-cohérente du déplacement de l’arc entre les électrodes a été réalisée. La simulation numérique a été faite pour des arcs en régimes DC, pulsé et AC à des pressions atmosphériques et inférieures. Les principales caractéristiques de l’arc ont été analysées et discutées. Les résultats obtenus ont été comparés avec les résultats expérimentaux et ont montré un bon accord.Ce modèle d’arc électrique est capable de prédire le comportement d’un arc de défaut dans des conditions aéronautiques. Des améliorations du modèle sont discutées comme perspectives de ce travail. / The ignition of an electric arc in the electric distribution system of an aircraft can be a serious problem for flight safety. The amount of information on this topic is limited, however. Therefore,the aim of this work is to investigate the electric arc behavior by means of experiment and numerical simulations.The MHD model of the LTE arc column was used and resolved numerically using the commercial software comsol Multiphysics. In order to describe plasma-electride interaction, the model had to be extended to include non-equilibrium effects near the electrodes. These zones were taken into account by means of current and energy conservation in the non-equilibrium layer. The correct matching conditions were developed and are described in the work. Validation of the model in the case of a free burning arc showed excellent agreement between comprehensive models and the experiment.This model was then extended to the case of the electric arc between rail electrodes in a 3D geometry. Due to electromagnetic forces the electric arc displaces along the electrodes. A self-consistent description of this phenomenon was established. The calculation was performed for DC, pulsed and AC current conditions at atmospheric and lower pressures. The main characteristics of the arc were analyzed and discussed. The results obtained were compared with the experimental measurements and showed good agreement.The model of electric arcs between busbar electrodes is able to predict the behavior of a fault arc in aeronautical conditions. Further improvements of the model are discussed as an outlook of the research.

Submitted by JOSIANE SANTOS DE OLIVEIRA (josianeso) on 2018-04-12T13:49:50Z No. of bitstreams: 1 Deborah Luisa Detânico Vieira_.pdf: 1504339 bytes, checksum: 49a2adc770aff79d216c818e22dea099 (MD5) / Made available in DSpace on 2018-04-12T13:49:50Z (GMT). No. of bitstreams: 1 Deborah Luisa Detânico Vieira_.pdf: 1504339 bytes, checksum: 49a2adc770aff79d216c818e22dea099 (MD5) Previous issue date: 2017-05-17 / Nenhuma / Com a crescente demanda de serviços de voz e, principalmente, dados móveis se fez necessário o desenvolvimento das tecnologias de quarta geração (4G). O padrão Long Term Evolution (LTE), desenvolvido pela Third Generation Partnership Project (3GPP), foi escolhido pela International Telecommunications Union (ITU) como tecnologia para atender os requisitos da quarta geração de serviços móveis. Para as operadoras inserirem esta nova tecnologia em suas redes existentes, se faz necessário um estudo meticuloso de planejamento, muito embora, na prática, este planejamento seja desenvolvido de forma empírica. O problema de planejamento de redes é conhecido e bem estudado no ramo da computação, conhecido como problema de recobrimento de conjuntos e classificado, pela sua complexidade, como NP-difícil. Dadas as características diferenciadas da arquitetura da rede do LTE, este trabalho busca resolver o problema de planejamento de redes de quarta geração (4G), utilizando uma modelagem matemática aplicada a uma metaheurística híbrida, composta de Algoritmo Genético e Busca Tabu. Almejase resolver o problema de cobertura de uma determinada região, cobrindo a maior área possível com o menor número possível de Base Stations (BS), visando ao planejamento com maior assertividade e redução do custo de implantação da rede 4G. / With the constantly demand of voice services and mostly in mobile data, there was the need the development of the mobile services of fourth generation (4G). The pattern Long Term Evolution, developed by the Third Generation Partnership Project (3GPP) was chosen by the International Telecommunications Union (ITU) as technology to attend the requirements of the fourth generation of mobile services. For the mobile operators introduce and apply this new generation in their own existing networks, they need to do an extensive research and planning, even if, in practical means, it is applied using the empirical way. The network planning problem is widely known and studied in computing area as set-covering problem ans classified as NPhard. Due the unique characteristics of network architecture of LTE, this work aims to solve the mobile’s fourth generation planning problem using a mathematics modelling apply to a hybrid metaheuristics, composed with Genetic Algorithm and Tabu Search. It aims solve the coverage problem of a specific region, covering the largest area possible with the fewest number of Base Sations (BS) possible, seeking the best compliance and cost reduction of the LTE network deployment.

Une antenne auto-complémentaire possède des caractéristiques radioélectriques très intéressantes en ce qui concerne l’élargissement de sa bande passante. Basée sur le principe de Babinet, l’auto-complémentarité permet en effet de maximiser la largeur de bande de par la complémentarité air-métal dans la structure de l’antenne. L’objectif de cette thèse est d’étudier quels pouvaient être les apports de l’auto-complémentarité dans le cas d’antennes à fortes contraintes d’intégration telles que celles utilisées pour les terminaux mobiles. Pour tester les limites de notre étude, nous avons choisi d’appliquer nos résultats à l’intégration d’antennes auto-complémentaires dans un objet communicant de type Smartphone multi-standards. Les antennes dites AC doivent par conséquent satisfaire de nombreux critères de performances tout en montrant leur capacité d’intégration. Celle-ci est rendue d’autant plus délicate, que la miniaturisation implique à son tour des phénomènes physiques limitant certaines performances, notamment en basse fréquence avec la nouvelle bande LTE. Dans une première étude, nous avons considéré différentes antennes et opté pour les antennes IFA-AC sur un plan de masse fini afin de couvrir initialement les bandes hautes DCS/PCS/UMTS et WLAN/LTE2600. Dans une seconde étude, nous avons amélioré leurs performances à l’aide d’éléments structurels nouveaux et interdépendants (éléments rayonnants de type double IFA), qui nous ont permis d’obtenir des résultats probants relatifs notamment à la couverture des bandes LTE800 et GSM. Enfin, nous avons complété notre projet en optimisant le lien radio par l’intégration de plusieurs éléments rayonnants AC sur un même PCB. / In this thesis we present the design and optimization of self-complementary antennas to be integrated into a Smartphone. A self-complementary antenna is known as a radio antenna with very interesting bandwidth characteristics. Self-complementarity is based on the Babinet’s principle which aims to maximize bandwidth by considering the complementarity of the air and metal in the construction of an antenna. To achieve an objective, the antennas must satisfy a number of criteria, both in terms of performance and also for the design methods and integration. Miniaturization is very sensitive and it is more difficult to implement an antenna because of the physical phenomena limiting performance, especially at low frequency with the new 4G band. In this study we considered initially the self-complementary-IFA on a finite ground plane size: 120x60mm² in order to cover the high frequencies: DCS/PCS/UMTS and WLAN/LTE2600. In the second part, we focused on the possibility of using some improvement techniques by adding structural element (capacitive elements and radiating elements). Various geometrical modifications applied to antenna structures have also been used to obtain results satisfying all criteria, including coverage of LTE800 bands and GSM bands. Several prototypes were used to compare the theoretical results and validate the concept of self-complementarity. We completed the project by developing a way to improve the radio link in natural environments. We have implemented several radiating self-complementary miniature multiband/broadband elements on the same PCB in order to implement the principles of diversity or MIMO.

Les antennes présentes dans la plupart des systèmes communicants comme les véhicules automobiles, les avions et les trains se multiplient et sont soumises à une contrainte d’intégration de plus en plus sévère. De nombreuses techniques de miniaturisation d’antennes existent et passent toutes par un compromis entre la taille et les performances (bande passante et/ou rendement de rayonnement). Pour les systèmes cités ci-dessus, les antennes sont souvent placées devant ou à proximité d’un réflecteur métallique (toit de véhicule, carlingue d’aéronef). Dans ce cas, l’épaisseur de système antennaire est une contrainte majeure et les métamatériaux de type Conducteur Magnétique Artificiel (CMA) ouvrent des perspectives intéressantes grâce à leurs propriétés électromagnétiques non conventionnelles. Cependant, pour les applications sub-GHz (RFID, LTE, PMR…), les CMA sont limités par les dimensions des cellules unitaires nécessaires à leur mise en œuvre (λg/4) ainsi que leur bande réduite de fonctionnement. Réduire leurs dimensions permet de rendre leur utilisation compatible avec le contexte des antennes miniatures intégrées. Ajouter l’agilité fréquentielle permet de palier le problème de la bande passante réduite dans le cas des antennes et des CMA miniaturisés en ajustant le fonctionnement du système antennaire sur une large bande passante. Cette thèse de doctorat propose d’étudier et de développer un nouveau système antennaire à faible profil composé d’une antenne miniature associée à une métasurface compacte reconfigurable en fréquence et compatible avec le standard NB-IoT dans la bande basse LTE (700 MHz – 960 MHz). / Antennas are now very integrated in several connected systems like cars, airplanes and trains. Many antenna miniaturization techniques exist and all go through a compromise between size and performance (bandwidth and/or radiation efficiency). For the systems mentioned above, the antennas are often placed near a metallic reflector (vehicle roof, aircraft cabin). Within this context, Artificial Magnetic Conductors (AMC) present an attractive reflector for low profile antennas which can take advantage of intrinsic zero reflection phase response to boost antenna performance without the need for thick quarter wave backplane. However, for sub-GHz applications (RFID, LTE, PMR ...), AMC are limited by the size of the unit cells necessary for their implementation (λg/4) as well as their reduced operating bandwidth. AMC miniaturization makes their use compatible with small antennas. Adding tunability restores the possibility of adjusting the operating frequency over a large bandwidth. This PhD thesis proposes to study and develop a new electrically small, low-profile antenna based on miniaturized and tunable AMC for the NB-IoT standard in low LTE band (700 MHz – 960 MHz).