WorldCat Identities

Laboratoire d'électronique, antennes et télécommunications (Sophia Antipolis, Alpes-Maritimes)

Overview
Works: 54 works in 54 publications in 2 languages and 54 library holdings
Roles: Other, Degree grantor
Publication Timeline
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Most widely held works by antennes et télécommunications (Sophia Antipolis, Alpes-Maritimes) Laboratoire d'électronique
Conception de systèmes multi-antennaires pour techniques de diversité et MIMO : application aux petits objets nomades communicants by Ibra Dioum( )

1 edition published in 2013 in French and held by 1 WorldCat member library worldwide

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
Antennes quasi-auto-complémentaires pour terminaux mobiles multi-standards by Cédric Requin( )

1 edition published in 2013 in French and held by 1 WorldCat member library worldwide

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
Nouveau modèle TLM thermique pour la dosimétrie numérique de structures fortement hétérogènes by Oualid Makhlouf( )

1 edition published in 2016 in French and held by 1 WorldCat member library worldwide

Depuis plusieurs années, le développement des technologies sans fil utilisant les ondes électromagnétiques dans différents milieux d'applications (télécommunications, médicales, militaires) ne cesse d'augmenter. Il devient donc nécessaire d'évaluer les effets de l'environnement sur les antennes en amont de leur conception afin d'optimiser la transmission entre les divers objets connectés. De plus, les études sur les systèmes utilisant les ondes électromagnétiques amènent à se poser un certain nombre de questions autour de l'interaction ondes/vivant, nous obligeant à considérer des modèles fortement hétérogènes tel que le corps humain.Face aux difficultés de mesures, la simulation permet de quantifier numériquement la puissance absorbée par les tissus au travers du DAS et l'élévation de la température correspondante. Dans ce domaine, la méthode TLM (Transmission Line Matrix) s'est révélée être particulièrement adaptée au calcul du DAS dans des structures fortement hétérogènes grâce à la colocalisation des champs au centre de la maille.Au cours de cette thèse, un outil basé sur la méthode TLM permettant d'effectuer des études dosimétriques en calculant le DAS et la température dans des milieux fortement hétérogènes a été développé. La première étape a été consacrée au développement d'un « module »pour calculer la DAS et la mise en place d'une interface pour lire les modèles voxélisés. Ensuite, un solveur thermique basé sur la TLM a été développé afin de simuler la température dans des milieux biologiques exposés aux ondes EM. Enfin, la comparaison avec le logiciel commercial CST a permis de valider notre outil et de l'appliquer par la suite pour étudier l'exposition d'une tête humaine au rayonnement d'un Smartphone modélisé par une PIFA fonctionnant à 900MHz
Une approche de modélisation au niveau système pour la conception et la vérification de systèmes sur puce à faible consommation by Ons Mbarek( )

1 edition published in 2013 in English and held by 1 WorldCat member library worldwide

Une solution de gestion de puissance d'un système sur puce peut être définie par une architecture de faible puissance composée de multiples domaines d'alimentation et de leur stratégie de gestion. Si ces deux éléments sont économes en énergie, une solution efficace en énergie peut être obtenue. Cette approche nécessite l'ajout d'éléments structurels de puissance et de leurs comportements. Une stratégie de gestion doit respecter les dépendances structurelles et fonctionnelles dues au placement physique des domaines d'alimentation. Cette relation forte entre l'architecture et sa stratégie de gestion doit être analysée tôt dans le flot de conception pour trouver la solution de gestion de puissance la plus efficace. De récentes normes de conception basse consommation définissent des sémantiques pour la spécification, simulation et vérification d'architecture de faible puissance au niveau transfert de registres (RTL). Mais elles manquent une sémantique d'interface de gestion des domaines d'alimentation réutilisable ce qui alourdit l'exploration. Leurs sémantiques RTL ne sont pas aussi utilisables au niveau transactionnel pour une exploration plus rapide et facile. Pour combler ces lacunes, cette thèse étend ces normes et fournit une étude complète des possibilités d'optimisation de puissance basées sur la composition et la gestion des domaines d'alimentation pour des modèles fonctionnels transactionnels utilisant un environnement commun USLPAF. USLPAF comprend une méthodologie alliant conception et vérification des modèles transactionnels de faible consommation, ainsi qu'une bibliothèque de techniques de modélisation et fonctions prédéfinies pour appliquer cette méthodologie
Conception de systèmes antennaires MIMO multi-standards LTE pour les nœuds relais by Lamia Sadaoui( )

1 edition published in 2018 in French and held by 1 WorldCat member library worldwide

To deploy the fourth generation called 4G/LTE or "LTE advanced", mobile operators face strong constraints: they must ensure a good geographic coverage but also an excellent quality of service. This requires new methods that go far beyond what has been implemented for GSM or 3G networks. The telecom industry has created the concept of "small cells" that reinforce the "macrocells" deployed by the operators. This thesis tries to provide a solution to this problem and more particularly through the development of antennas for a product called "smart cell". This study, supported by the FUI project NETCOM, should enable mobile operators to extend the coverage and capacity of their networks at a lower cost while maintaining a good quality of service. To do that, the aim of this thesis more particularly is the design of a multi-band multi-antennas MIMO system (Multiple-Input Multiple-Output) dedicated to relay nodes for the deployment of the fourth generation 4G/LTE or "LTE advanced". The antenna design considers the coverage of the three LTE operating frequency bands and must be compatible with them. The (700-900 MHz) frequency band is used for the LTE 700 and LTE 800 bands, (1710-1880 MHz) for the GSM 1800/LTE 1800 bands and the last (2500-2690 MHz) for the LTE 2600 bands. In our first study, a reference system with 4 access was studied in simulation and measured, for only the low band 700-900 MHz. In a second study, we tried to cover the other two higher bands to have a tri-band system using the parasitic elements to get a three-band MIMO system with 4 access. We studied then, the influence of the environment close to the antenna system, with the presence of a metallic radiator. As we often encounter a frequent problem in multi-antenna systems which is the coupling problem between the different access of a multi antenna system, so we have studied and realized a decoupling technique. This technique was used to enhance the isolation between the different access
Étude et conception d'un nouveau système intégré à une plateforme de monitoring pour la détection des décharges partielles en UHF pour les équipements électriques by Alexandre Marchal( )

1 edition published in 2019 in French and held by 1 WorldCat member library worldwide

SENSeOR has developed a system dedicated to the temperature monitoring for medium and high voltage equipments in order to avoid certain failures that could have major consequences on the electrical grid. However, phenomena other than the increase of the temperature are also present in these equipments like partial discharges (PD) whose detection would make it possible to establish a reliable and effective diagnosis of the apparatus state of health. This is what the presented research work suggests. For this, we will present the characteristics defining the insulation of an electrical equipment and the different properties of the partial discharge phenomenon. We also expose the problems and objectives as well as the interest to focus on the UHF method as a detection method and why targeting on Ultra-Wide Band (UWB) antenna topologies as PD sensors, and why this type of antenna, is a strong ally in the PD detection. The design of a new printed and miniature UWB antenna usable in a harsh and restricted environment, typically a metallic cavity of a medium-voltage cell, is then presented along with the technique used to widen its bandwidth. The last part of this work is dedicated to the development of the complete UHF PD detector with the description of hardware and firmware developments. Finally, various tests set up in laboratory and in situ in order to validate and characterize the designed system are presented
Conception d'antennes à base de métal liquide pour applications multiples by Mathieu Cosker( )

1 edition published in 2017 in French and held by 1 WorldCat member library worldwide

Today, electronic is an integral part of our lives. Indeed, more and more objects integrate electronics to connect each other, this is the Internet of Things (IoT). All of these wireless devices need one or more antennas. Furthermore, It's useful to develop new materials to realize new antennas that fit with new constraints: smaller and flexible objects, more and more sensors and less and less consuming.In this context, we have focused this research on antenna structures based on metals which are liquid at room temperature to realize conformable antennas of complex shapes combining 3D printing, reconfigurable antennas and radiant structures with the ability to sensor. In this manuscript, antenna prototypes with these characteristics have been simulated, realized and measured
Étude et conception d'antennes miniatures et directives à polarisation circulaire pour lecteurs RFID UHF by Sylvain Pflaum( )

1 edition published in 2013 in French and held by 1 WorldCat member library worldwide

RFID technology is now a part of our daily lives. The corresponding applications are more and more numerous and widespread. This work having been done in the framework of the PACID textile project, this thesis has the ambition to research innovative solutions for RFID readers in order to enhance the management, the traceability and the security of the industrial and commercial textiles.Towards this end, the antenna reader has to be miniature while being low-cost, directive and in circular polarization in the RFID UHF band (0.865-0.868 GHz). The two main technological challenges that we have faced for the reader antenna is managing its main direction of propagation to restrict and control the reading zone as well as the miniaturization of its size in order to easily integrate it into any environment. To respond to this problem, the research areas discussed in this manuscript were: The obtaining of the circular polarization using short-circuited resonators. The study and design of microstrip antennas based on EBG (Electromagnetic Band Gap). Type metamaterials to improve their directivity by using the original properties of these structures. The research of new miniaturization techniques for printed antennas by introducing a new EBG ground plane
Caractérisation numérique d'antennes VLF-LF en environnement réel by David Saintier( )

1 edition published in 2018 in French and held by 1 WorldCat member library worldwide

Submarine communications are the main usage of the very low frequency (VLF). This frequency band allows to radiate up to a few tens meter of depth and to a very long distance. Antennas for such telecommunications are necessarily small in regard to the wavelength. However, these structures are composed of hundred meters of thin metallic cables and their locations are often chosen for their dielectric characteristics or the structural advantage provided by the relief. To evaluate such antennas, we propose to use a home-made software, based on the TLM method. Such technique can be efficient for studying wide band electromagnetic problems in complex dielectric environment. Then we have improved the TLM Thin Wire model and we have evaluated its performances in realistic environment. In this document, we present our work and its validation by comparing our results to those obtained with the commercial software FEKO, based on the MoM, considered as the most suitable technique for this kind of problem. A solution assuring a good accuracy of the model for an arbitrary orientation of the Thine Wire in the 3D cartesian grid was proposed. We have also specified the limitations of the bent wire and the wires junction. In addition, we have studied the interaction between the wire and inhomogeneous media. This is an ambitious problem for which we brought some elements of answer but which remains a challenge. Finally, we have tested our software on some realistic antenna systems. The simulations of a valley span T antennas system allow to understand the functioning of such radiating structure and to show the interest of our method. The computation times are significantly lower with the TLM method than with FEKO to deal with antennas above such complex ground. However, the simulations of a Trideco antenna with aerial or buried radial ground plane showed the actual limitations of the TLM software which remains handicapped by an insufficient accuracy of the wires junction model and the inhomogeneous media interactions
Développement de système antennaire pour les communications 5G by Tran Quang Khai Nguyen( )

1 edition published in 2020 in English and held by 1 WorldCat member library worldwide

The work in this thesis has been funded by the French FUI project MASS-START (2017-2020). The project aims at the integration of 5G compatible baseband and radio subsystems into an Over-Air-Interface-based 5G terminal and gNodeB demonstrator, and the antenna array for end-to-end Multiple Input Multiple Output link experimentation. The scope of the thesis concerns the design and assessment of antenna systems that are to be used in the project.At 5G Frequency Range 1 band, the work concentrates on the development of a methodology to design antenna with a matching circuit for mobile terminals with limited area. The bandwidth limitation is evaluated using Quality-Factor. A Particle Swarm Optimization algorithm is proposed and examined in different antenna designs for mobile terminals. The final design demonstrates a system with three non-resonating coupling elements covering most of the sub-6GHz bands of 5G. At 5G Frequency Range 2 band, more precisely band n258 of Europe, different types of array antennas are studied. The work first checks two types of feeding for a patch antenna that can be integrated into Printed Circuit Board to have a low profile antenna and ease the fabrication procedure. The designs are later fabricated and experimentally evaluated. With a Millimeter-Wave array at hand, we proceed a measurement campaign in which the effects of the user's finger at close proximity of the antenna are evaluated. The losses due to absorption, reflection, diffraction are quantified and compared with numerical estimations in literature. A system of multiple end-fire arrays placed at different locations in a terminal is also studied showing the compromising effectiveness if one array is severely blocked
Caractérisation de la performance temporelle et de la consommation électrique de systèmes embarqués basés sur des plates-formes multiprocesseurs/coeurs et mettant en oeuvre du logiciel temps réel : FORECAST : perFORmance and Energy Consumption AnalysiS Tool by Joffrey Kriegel( )

1 edition published in 2013 in French and held by 1 WorldCat member library worldwide

The number of available commercial platforms is constantly increasing. The choice of an architecture that fit as much as possible the requirements is therefore more and more complex. This is even more real with the availability of recent multiprocessors architectures. As a consequence, methodologies with their associated tools are required in order to quickly evaluate future platforms, so that choices can be made early in the design flow. So far, evaluating either the performance or the power consumption of a dedicated platform was performed through executing benchmarks and applications on this platform. In this thesis, a new methodology with its associated tools, called FORECAST, is proposed to model both the hardware and software of a system, and then to estimate its performance and its power consumption. Our methodology is based on efficient models, easy to characterize using only information provided by constructor datasheets. Moreover, our approach is able to automatically generate an executable code of the system that can be simulated on the host machine. This simulation allows a rapid execution of multiple test cases. Our approach is therefore well adapted for performing architecture exploration. A lot of experimentations have been performed using our tool FORECAST for different applications (H.264 video decoder, radio application, benchmarks. . .) and different hardware platforms. Results obtained both in performance and in power consumption have then been compared with existing platforms (OMAP3, OMAP4, i.MX6, QorIQ. . .), but also with two collaborative projects, OpenPeple (ANR) and COMCAS (Catrene), dealing also with performance and power estimations. The comparison demonstrates the accuracy of our approach as the estimation is always below a 20% error margin. These experimentations have also shown that our methodology provides a very efficient ratio between the modeling effort and the accuracy of the estimations
Conception de petits réseaux d'antennes reconfigurables ou "Small Cells" pour le standard 5G by Assane Ngom( )

1 edition published in 2019 in French and held by 1 WorldCat member library worldwide

Les communications mobiles grand public, le téléchargement de vidéos et l'utilisation d'applications mobiles représentent l'essentiel de l'utilisation actuelle des ressources radio dans les réseaux 4G ; mais pour que le spectre des usages et la diversité des utilisateurs soient grandement élargis, de nombreux efforts de recherche et de nombreuses propositions commencent à émerger pour la mise en place d'un nouveau standard appelé 5G, qui vise des secteurs très variés et qui sont des piliers importants d'une société : l'énergie, la santé, les médias, l'industrie ou le transport.Pour répondre à ces défis, ce nouveau standard devra regrouper plusieurs technologies parmi lesquelles, la réalisation d'un réseau Ultra-Dense (UDN) pour obtenir une couverture plus dense, plus robuste aux obstacles et augmenter la capacité du réseau. En conséquence, le réseau cellulaire ultra-dense est en train de devenir l'une des principales caractéristiques des réseaux cellulaires 5G. L'idée de base est d'obtenir des nœuds d'accès aussi proches que possible des utilisateurs finaux. L'obtention de cette solution prometteuse est réalisée par le déploiement dense de petites cellules appelées « Small Cells » dans des hotspots où un trafic immense est généré, en utilisant les ondes millimétriques pour étendre la bande passante de transmission.Ces « smalls cells » doivent optimiser au mieux la réception du signal selon l'emplacement de l'utilisateur par rapport à l'antenne pour concentrer l'émission du signal dans les directions utiles, par l'utilisation de réseaux d'antennes reconfigurables en diagramme et à fort gain. Cette méthode évite ainsi d'utiliser toute la puissance disponible pour émettre « à l'aveugle » en espérant tomber sur le terminal.Les travaux menés dans le cadre de cette thèse s'inscrivent dans ce contexte. L'objectif donc consiste à concevoir et réaliser un petit réseau d'antennes ou « Small Cells » travaillant dans les bandes de fréquences millimétriques doté d'une capacité à changer la direction du faisceau selon les besoins des utilisateurs. Une technique de reconfiguration de diagramme de rayonnement avec changement de polarisation appliquée sur un réseau d'antennes planaires a été développée. Ce manuscrit se divise comme suit : après un rappel des objectifs de la 5G ainsi que ses exigences dans le chapitre 1, nous avons introduit dans le chapitre 2, les architectures et la théorie des différents réseaux d'antennes, ainsi que les différentes techniques de dépointage de faisceaux. Le troisième chapitre est consacré à la conception d'un élément rayonnant en forme de croix à double polarisation et diagramme de rayonnement reconfigurable par utilisation d'éléments parasites commutables. Cet élément rayonnant a ensuite été utilisé dans le chapitre 4, pour concevoir des sous-réseaux et réseaux d'antennes multi-ports, reconfigurables, à fort gain
Étude de circuits d'alimentation actifs d'antennes imprimées by Yassine Turki( Book )

1 edition published in 2001 in French and held by 1 WorldCat member library worldwide

This work of thesis can bit spit into four main aspects. A first study has been made concerning discrete and continuous microwave phase shifters used in phased arrays antennas. The second part concerning tunable antennas exposes two antennas integrating their feeding circuit (phase shifter-amplifier) by using a multilayer structure technology, and also a parametric study concerning feeding of a shorted patch with coplanar waveguide. His work is completed by the insertion of a varator diode to control the radiating element resonance frequency and validate this type of feeding. To enhance the matching and polarization characteristics of patch antennas, two self-adjusting antennas have been developed. The first one is able to change its resonance frequency if the radiating element is inclined to be mismatched due to a perturbation in its close environment. The second antenna has the particularity to change its polarization direction depending on the received electromagnetic field. These antennas and their feedback circuits are exposed and constitute the third part of this thesis. In the last aspect study has been done concerning the possibility to control the printed reflect arrays radiation patterns by using active devices
Système embarqué autonome en énergie pour objets mobiles communicants by Chiraz Chaabane( )

1 edition published in 2014 in English and held by 1 WorldCat member library worldwide

The increasing number and complexity of applications that are embedded into wireless mobile communicating devices (mobile phone, PDA, etc.) implies an increase of energy consumption. In order to limit the impact of pollution due to battery waste and CO2 emission, it is important to conduct an optimization of the energy consumption of these communicating end devices. This thesis focuses on energy efficiency in sensor networks. It proposes new approaches to handle mobile communicating objects. First, we propose a global sensor network architecture and a new energy-efficient mobility management approach for IEEE 802.15.4/ZigBee end devices. This new approach is based on the link quality estimator (LQI) and uses a speculative algorithm. We propose and evaluate two different speculative algorithms. Then, we study and evaluate the energy efficiency when using a rate adaptation algorithm that takes into account the communication channel conditions. We first propose a mobility-aware rate adaptation algorithm and evaluate its efficiency in our network architecture. Then, we propose and evaluate a hybrid rate adaptation algorithm that relies on more accurate link channel estimation. Simulations conducted all along this study show the energy-efficiency of our proposed approaches and the improvement of the nodes' connectivity
Antennes implantées et système de localisation pour petits animaux utilisant la technologie RFID by Van Hieu Nguyen( )

1 edition published in 2018 in French and held by 1 WorldCat member library worldwide

Le suivi des petits animaux utilisés dans le cadre de tests de laboratoire et l'analyse de leur comportement à distance, à faible coût et en temps réel suscitent depuis longtemps l'intérêt des chercheurs. Ceux-ci peuvent se faire par l'implantation de capteurs sans fils miniatures qui nécessitent des composants vitaux dont le plus problématique est l'antenne. En effet, la principale difficulté dans la conception d'antennes pour les dispositifs de communication bio-implantables est de fournir une structure rayonnante efficace et ce, malgré les contraintes de volume et le fort impact des tissus biologiques qui l'entourent. Si de nombreuses études ont porté sur l'utilisation d'antennes implantées dans la bande MICS (Medical Implant Communications Service) (402-405 MHz), il faut noter qu'à ces fréquences, la taille des antennes peut être un inconvénient réel dans le cas de petits animaux, d'où une recherche de miniaturisation. Une alternative consiste en l'utilisation de la technologie RFID (Radio-Frequency Identification) dans la bande UHF à 868 MHz. En effet, elle présente deux avantages primordiaux : elle facilite l'implantation du tag et ne nécessite pas l'ajout d'une batterie pour alimenter le périphérique implanté. Ce travail de thèse fait suite à un projet collaboratif financé par l'ANR (Agence Nationale de la Recherche) dans le cadre du Labex UCN@Sophia et qui a pour objectif la conception d'un système sans fils incluant aussi bien les tags RFID implantables, les antennes du lecteur et le lecteur connecté à un ordinateur se chargeant de la gestion centralisée des informations sur un serveur pour le suivi et la collecte de données de souris de laboratoire. Ce mémoire présente la conception d'antennes implantées pour tags RFID dans un modèle homogène représentant le corps d'une souris. Après l'analyse d'un bilan de liaison permettant de calculer les performances minimales de l'antenne implantée à concevoir pour une communication fiable et efficace, des antennes tags RFID passifs en 2D et en 3D ont été optimisées par différentes techniques pour atteindre des structures finales implantables ou injectables au dos d'une souris. Une caractérisation des solutions proposées en termes d'impédance, de champs E et H et de DAS (Débit d'Absorption Spécifique) a ensuite été effectuée dans un fantôme homogène. Enfin, un système d'interrogation permettant d'estimer la position de l'animal via la récupération du RSSI (Received Signal Strength Indicator) est présenté
Étude et minimisation du facteur de qualité des antennes pour de petits objets communicants by Oumy Diop( )

1 edition published in 2013 in French and held by 1 WorldCat member library worldwide

Currently, wireless devices play an important role in everyday life. For ease-of-use, these devices are becoming smaller and require very small antennas. However, the size reduction of these antennas necessarily implies a degradation of their performance. Consequently, the design of electrically small antennas (ESA) requires a very good theoretical understanding of the electromagnetic phenomenon that takes place, especially in terms of accurate performance that can be expected for an ESA with given dimensions. An important parameter of an ESA is its intrinsic quality factor since it is inversely proportional to its impedance bandwidth. Indeed, maximizing the matching bandwidth of an antenna consists in minimizing its quality factor. Facing this problem, many researches have been developed to determine the possible limits of the quality factor of ESA. The first research axis of this thesis is to study the quality factor of ESA to determine whether optimal dimensions exist to approach the fundamental quality factor limits. The second part of the thesis studies miniature antennas for biomedical implants operating at 2.45 GHz. These antennas are printed on a specific microelectronic substrate to ensure a better resolution in terms of metallic traces in order to reduce the size and allow easier integration to facilitate interconnections with RF front-end. The challenge consists in maximizing the performance of these antennas. The presented results are supported by means of electromagnetic models and simulations on one hand. Also, several prototypes are fabricated to validate these simulations
Evaluation of power management strategies on actual multiprocessor platforms by Jabran Khan Jadoon( )

1 edition published in 2013 in English and held by 1 WorldCat member library worldwide

The purpose of this study is to investigate how power management strategies can be efficiently exploited in actual platforms. Primarily, the challenges in multicore based embedded systems lies in managing the energy expenditure, determining the scheduling behavior and establishing methods to monitor power and energy, so as to meet the demands of the battery life and load requirements. The work presented in this dissertation is a study of low power-aware strategies in the practical world for single and multiprocessor platforms. The approach used for this study is based on representative multiprocessor platforms (real or virtual) to identify the most influential parameters, at hardware as well as application level, unlike many existing works in which these parameters are often underestimated or sometimes even ignored. The work analyzes and compares in detail various experimentations with different power policies based on Dynamic Voltage and Frequency Scaling (DVFS) and Dynamic Power Switching (DPS) techniques, and investigates the conditions at which these policies are effective in terms of energy savings. The results of these investigations reveal many interesting and notable conclusions that can serve as prerequisites for the efficient use of power management strategies. This work also shows the potential of advanced domain specific power strategies compared to real world available strategies that are general purpose based in their majority. Finally, some high level consumption models are derived from the different energy measurement results to let the estimation of power management benefits at early stages of a system development
Étude d'un système d'imagerie microonde multistatique-multifréquence pour la reconstruction d'objets enfouis by Erwan Guillanton( Book )

1 edition published in 2000 in French and held by 1 WorldCat member library worldwide

Ce travail de thèse porte sur l'utilisation du rayonnement électromagnétique pour la détection et la reconstruction d'objets ou de structures hétérogènes enfouis ou enterrés dans des milieux optiquement opaques. Un processus d'imagerie microonde se décompose en deux phases : l'acquisition des champs diffractés et l'inversion numérique de ces mesures par des algorithmes de reconstruction. Ce travail porte principalement sur le premier aspect, à savoir la mise au point d'un prototype d'imageur microonde ultra large bande (ULB) et multistatique pour éviter un déplacement mécanique ou manuel des antennes et ainsi permettre une acquisition rapide du champ diffracté sur la ligne de mesure. Les antennes ULB du système d'imagerie ont été optimisées pour des applications militaires et humanitaires (détection des mines antipersonnel), génie civil (épaisseur des chaussées, auscultation des ouvrages d'art en maçonnerie), géophysiques et archéologiques. Des résultats expérimentaux sur sites test sont présentés. Toutefois, le deuxième aspect est également abordé par l'intermédiaire du développement d'un code de modélisation 3D du problème d'interaction ondes électromagnétiques-matières résolu par une méthode de différences finies harmoniques qui permettra d'étendre au cas tridimensionnel les algorithmes d'imagerie existant au laboratoire afin de prendre en compte la polarisation de l'onde émise et de traiter des modèles plus réalistes
Modélisation au niveau transactionnel de l'architecture et du contrôle relatifs à la gestion d'énergie de systèmes sur puce by Hend Affes( )

1 edition published in 2015 in French and held by 1 WorldCat member library worldwide

Embedded systems-on-chip (SoC) invade our daily life. With advances in semiconductor technology, these systems integrate more and more complex and energy-intensive features which generate increasing computation load and memory size requirements. While the complexity of these systems is a key trend, energy consumption has emerged as a critical factor for SoC designers. In this context, we have studied a modeling transactional level approach allowing a description of a clock tree and its management structure to be associated with a functional model, both described at the same abstraction level. This structure developed in a separation of concerns approach provides both the interface to the power consumption management of the hardware components and the application software. All the models developed are gathered in a C++ ClkArch library. To apply to a SystemC-TLM architecture model a clock tree intent with its control part, we propose a methodology based on three steps: specification, modeling and simulation. A verification step based on simulation is also considered using contracts of assertion type. This work aims to build a modelling approach on current design tools. So we propose a representation of a clock and power management structure in the IP-XACT standard allowing a C++ description of the SoC power management structures to be generated. Finally, a power management strategy based on the global functional states of the components of the system architecture is proposed. This strategy avoids local decision-making unsuited to optimized overall power/energy management
Gestion des ressources et de l'énergie orientée qualité de service pour les systèmes robotiques mobiles autonomes by Dinh Khanh Ho( )

1 edition published in 2020 in English and held by 1 WorldCat member library worldwide

Mobile robotic systems are becoming more and more complex with the integration of advanced sensing and acting components and functionalities to perform the real required missions. For these technical systems, the requirements are divided into two categories: functional and non-functional requirements. While functional requirements represent what the robot must do to accomplish the mission, non-functional requirements represent how the robot performs the mission. Thus, the quality of service and energy efficiency of a robotic mission are classified in this category. The autonomy of these systems is fully achieved when both functional and non-functional requirements are guaranteed without any human intervention or any external control. However, these mobile systems are naturally confronted with resource availability and energy capacity constraints, particularly in the context of long-term missions, these constraints become more critical. In addition, the performance of these systems is also influenced by unexpected and unstructured environmental conditions in which they interact. The management of resources and energy during operation is therefore a challenge for autonomous mobile robots in order to guarantee the desired performance objectives while respecting constraints. In this context, the ability of the robotic system to become aware of its own internal behaviors and physical environment and to adapt to these dynamic circumstances becomes important.This thesis focuses on the quality of service and energy efficiency of mobile robotic systems and proposes a hierarchical run-time management in order to guarantee these non-functional objectives of each robotic mission. At the local management level of each robotic mission, a Mission Manager employs a reinforcement learning-based decision-making mechanism to automatically reconfigure certain key mission-specific parameters to minimize the level of violation of required performance and energy objectives. At the global management level of the whole system, a Multi-Mission Manager leveraged rule-based decision-making and case-based reasoning techniques monitors the system's resources and the responses of Mission Managers in order to decide to reallocate the energy budget, regulate the quality of service and trigger the online learning for each robotic mission.The proposed methodology has been successfully prototyped and validated in a simulation environment and the run-time management framework is also integrated into our real mobile robotic system based on a Pioneer-3DX mobile base equipped with an embedded NVIDIA Jetson Xavier platform
 
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Alternative Names
Centre national de la recherche scientifique (France). Unité de recherche associée (D 1400)

Centre national de la recherche scientifique (France). Unité mixte de recherche (6071)

Centre national de la recherche scientifique (France). Unité mixte de recherche (7248)

LEAT

Université Côte d'Azur. Laboratoire d'électronique, antennes et télécommunications

Université de Nice-Sophia Antipolis. Laboratoire d'électronique

Université de Nice-Sophia Antipolis. Laboratoire d'électronique, antennes et télécommunications

Languages
French (15)

English (5)