Dissertations / Theses on the topic 'Communication à champ proche (NFC)'
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Dieng, Mouhamadou. "Etude de systèmes d’auto-adaptation pour les systèmes de Communication en Champ Proche dits NFC (Near Field Communication)." Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20010/document.
Full textNear Field Communication (NFC) is a standardized communication technology derived from Radio Frequency Identification (RFID). NFC uses magnetic induction between two antennas in order to transfer data and/or energy between two electronic devices. NFC operating frequency is 13.56 MHz.Due to the wide range of devices and applications, a predefinition of antenna geometry and corresponding electrical parameters is difficult. In fact, each device shows different antennaphysical characteristics ; On the Other hand, the NFC control integrated circuit (IC) is generic and does not depend on antenna nor a device. Therefore, each integrator associates the NFC IC with a specific antenna for each device. Current NFC transmission modules require the antenna circuitry to be matched with the integrated circuit. Nowadays, the matching is performed manually using a time consuming iterative procedure for each device. Moreover, the matchingcan be done only once at the device design level, regardless of the communication mode (reader, card or peer-to-peer) and regardless of the secondary device influence on the primary antenna characteristics.In this manuscript, we propose a detailed description of the electrical performances of NFC Systems. Then an accurate and complete analytical electrical model of NFC antennas is proposed.Finally, we develop a new technic of automatic adaptation of the matching network in order to optimize the electrical performances in the transmission phase in terms of energy transfer from the reader to the transponder
Quignon, Jérémy. "Chargement sans fil par NFC." Electronic Thesis or Diss., Aix-Marseille, 2022. http://www.theses.fr/2022AIXM0462.
Full textThe PHD context is focused on the NFC market and its extension allowing wireless charging. This new functionality allows to charge wearable products that cannot be charged with the wireless charging technologies available on the market today. The PHD objective is to develop a solution for these wearable products, such as connected watches and bracelets, wireless headphones, connected glasses, ... This solution must satisfy NFC standards while seeking to optimize the performance of power transfer
Lerch-Malherbe, Magali. "La trajectoire d'innovation de la naissance d'un écosystème d'affaires : une approche multiniveaux : Le cas du développement des services mobiles NFC." Caen, 2014. http://www.theses.fr/2014CAEN0507.
Full textThe open innovation movement, which has been emerging since the early 21th century, is at the origin of the emergence of business ecosystems (BE). They integrate players who have their competences and their roles co-evolving to manage the challenges of each stage of their life cycles. But few studies consider this dynamic dimension of the BE and especially its first stage: the birth. Specifically, it evolves along an innovation trajectory which leads the actions to define a new offer. Based on qualitative research and on process approach, this study focuses on the case of the emergence of a business ecosystem in the field of contactless mobile services. We conduct a multilevel analysis through the global process of this BE's innovation trajectory and the local process of the experimental projects which are articulated along this path. We are 'coking at these two processes as places, which include a managerial logic contributing to build key competences and a socio-political logic providing power strategies between players and their roles definition. Our results focus on two analytical levels. At the global level, the main challenge is to define a shared collective vision. It revolves around two dimensions: a technical dimension (the dominant design) and an economic dimension (the business model). It is formalized through key competences building which, in turn, defines the roles of the members. In this dynamic, competences related to "use context sensitivity" are crucial: they enable BE's intégration until the trajectory lock-in, then its efficiency through the generation of new alternatives which may lead to some bifurcations (positive ambiguity). At the local level, experimental projects promote the confrontation of individuals' strategies. They generate the building of competences which capitalize along the trajectory or question the collective vision
Tornambé, Anthony. "Modélisation système et développement d'antennes multistandards pour objets de paiement sans contact et de communication NFC." Electronic Thesis or Diss., Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4360.
Full textThe thesis context is focused on the NFC market, secure cards and contactless paiement which are in strong development in recent years. The objective is to develop a simulation environment to design NFC features for mobile devices as smartphone or tactile tablet which satisfy NFC standards
Lesas, Anne-Marie. "Vers un environnement logiciel générique et ouvert pour le développement d'applications NFC sécurisées." Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0286/document.
Full textIn the field of electronic transactions and payment with a smart card, the Near Field Communication (NFC) standard has stood out against other candidate technologies for secure mobile contactless transactions for payment, access control, or authentication. Secure mobile contactless services are based on the card emulation mode of the NFC standard which involves a smart card type component with restricted access called "Secure Element" (SE) in which sensitive data and sensitive functions are securely stored and run. Despite considerable standardization efforts around the SE ecosystem, the proposed models for the implementation of SE are complex and suffer from the lack of genericity, both to offer abstraction mechanisms, for the development of high-level applications, and for the implementation and verification of applications security constraints.The objective of the thesis is to design and realize a software environment based on a generic model that complies with established standards and which is not very sensitive to technological evolutions. This environment should enable non-experts to develop multi-platform, multi-mode, multi-factor SE-based applications running into the NFC smartphone
Stiti, Oussama. "Étude de l'Urbanisation des Accès Virtuels et Stratégie de Métamorphose de Réseaux." Electronic Thesis or Diss., Paris 6, 2015. http://www.theses.fr/2015PA066632.
Full textVirtualization was originally introduced in networks to reduce maintenance and deployment costs. It has experienced tremendous growth and reshaped the landscape of IT and ITC networks. Virtualization permits the sharing of physical resources for instantiating isolated virtual machines despite the fact that it is drawing its resources from the same physical hardware. More recently NFV (Network Functions Virtualization) appeared, it allows to virtualize entire classes of network functions node in blocks that can connect to create communication services. In this thesis we virtualize the access network nodes, namely Wi-Fi access points. The Wi-Fi became one of the hot-topic technology for mobile operators, it allows them to offload some of the customers’ data traffic via hotspots. The problem that arises in such a mechanism is the existing wireless standards, and mobile devices connection management software have not been developed for this purpose. The Hotspot2.0 standard was created to overcome this limitation, by making the Wi-Fi experience similar to the cellular in terms of roaming, transparency and security. We have in our work, applied the concept of NFV by virtualizing these brand new Wi-Fi access points. One of the problems that we faced is the high security required by such standard, including the provisioning of client credentials in public areas. In our thesis we propose an innovative architecture for the repatriation of these credentials through NFC terminals. These same terminals will be used for access points’ urbanization by allowing users to create their own Wi-Fi virtual access point on the fly. The last aspect of this thesis is related to the management of virtualized entities changing communication patterns of legacy networks. In this context, SDN (Software Defined Network) emerged in data centers to redefine the way we think about networks, and is designed for virtualized environments. In this thesis we brought SDN to the edge of the network in our Wi-Fi virtual access points. More than a new paradigm of networks communications, we will see that NFV/SDN in Wi-Fi networks will in the near future make Wi-Fi networks more flexible, open and scalable
Tornambé, Anthony. "Modélisation système et développement d'antennes multistandards pour objets de paiement sans contact et de communication NFC." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4360/document.
Full textThe thesis context is focused on the NFC market, secure cards and contactless paiement which are in strong development in recent years. The objective is to develop a simulation environment to design NFC features for mobile devices as smartphone or tactile tablet which satisfy NFC standards
El, Madhoun Nour. "Towards more secure contact and NFC payment transactions : new security mechanisms and extension for small merchants." Electronic Thesis or Diss., Sorbonne université, 2018. http://www.theses.fr/2018SORUS168.
Full textEMV is the standard implemented to secure the communication, between a client’s payment device and a PoS, during a contact or NFC purchase transaction. It represents a set of security messages, exchanged between the transaction actors, guaranteeing several important security properties. Indeed, researchers in various studies, have analyzed the operation of this standard in order to verify its reliability: unfortunately, they have identified several security vulnerabilities that, today, represent major risks for our day to day safety. Consequently, in this thesis, we are interested in proposing new solutions that improve the reliability of this standard. In the first stage, we introduce an overview of the EMV security payment system and we survey its vulnerabilities identified in literature. In particular, there are two EMV security vulnerabilities that lead to dangerous risks threatening both clients and merchants: (1) the confidentiality of banking data is not guaranteed, (2) the authentication of the PoS is not ensured to the client’s device. Therefore, our interests move in the second stage to address these two weaknesses. We first review a selection of the related works that have been implemented to solve these vulnerabilities, and then, in order to obtain better results than the related works, we propose a new secure contact and NFC payment system that includes four innovative security mechanisms. Finally, in the third stage, we adapt our first security mechanism in the context of a new NFC payment architecture. This architecture is especially destined for small merchants, allowing them to take advantage of their NFC smartphones for use directly as NFC readers
Stiti, Oussama. "Étude de l'Urbanisation des Accès Virtuels et Stratégie de Métamorphose de Réseaux." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066632/document.
Full textVirtualization was originally introduced in networks to reduce maintenance and deployment costs. It has experienced tremendous growth and reshaped the landscape of IT and ITC networks. Virtualization permits the sharing of physical resources for instantiating isolated virtual machines despite the fact that it is drawing its resources from the same physical hardware. More recently NFV (Network Functions Virtualization) appeared, it allows to virtualize entire classes of network functions node in blocks that can connect to create communication services. In this thesis we virtualize the access network nodes, namely Wi-Fi access points. The Wi-Fi became one of the hot-topic technology for mobile operators, it allows them to offload some of the customers’ data traffic via hotspots. The problem that arises in such a mechanism is the existing wireless standards, and mobile devices connection management software have not been developed for this purpose. The Hotspot2.0 standard was created to overcome this limitation, by making the Wi-Fi experience similar to the cellular in terms of roaming, transparency and security. We have in our work, applied the concept of NFV by virtualizing these brand new Wi-Fi access points. One of the problems that we faced is the high security required by such standard, including the provisioning of client credentials in public areas. In our thesis we propose an innovative architecture for the repatriation of these credentials through NFC terminals. These same terminals will be used for access points’ urbanization by allowing users to create their own Wi-Fi virtual access point on the fly. The last aspect of this thesis is related to the management of virtualized entities changing communication patterns of legacy networks. In this context, SDN (Software Defined Network) emerged in data centers to redefine the way we think about networks, and is designed for virtualized environments. In this thesis we brought SDN to the edge of the network in our Wi-Fi virtual access points. More than a new paradigm of networks communications, we will see that NFV/SDN in Wi-Fi networks will in the near future make Wi-Fi networks more flexible, open and scalable
Hasnaoui, Amir. "Intention d'adoption et utilisation d'une technologie émergente : le cas de la NFC appliquée aux systèmes de paiement électronique de détail (paiement sans contact)." Thesis, Evry, Institut national des télécommunications, 2012. http://www.theses.fr/2012TELE0005.
Full textWith the emergence of near-field technology (NFC), mobile terminal have become a true instrument of contactless payment. This type of system is a new opportunity to boost the electronic payment systems (EPS) for the micropayment. The objective of this research is to develop a model and measurement tools to handle and to identify factors influencing the acceptance of these systems. Based on the paradigms of the acceptance of technology and research around the SPE, we have developed a conceptual model which integrates the UTAUT and TTF. This model allows both to consider the adoption strategies of individuals and their intention to adopt. Indeed, perceived usefulness, perceived ease of use and facilitating conditions are no longer sufficient for a technology to be adopted. The capabilities of this technology have to match the tasks that the user will perform. Our result have been measured and validated thanks to structural equations analysis of data collected from a sample of 629 individuals
Bouazzouni, Mohamed Amine. "Processus sécurisés de dématérialisation de cartes sans contact." Phd thesis, Toulouse, INPT, 2017. http://oatao.univ-toulouse.fr/19488/1/BOUAZZOUNI_MohamedAmine.pdf.
Full textEl, Madhoun Nour. "Towards more secure contact and NFC payment transactions : new security mechanisms and extension for small merchants." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS168.
Full textEMV is the standard implemented to secure the communication, between a client’s payment device and a PoS, during a contact or NFC purchase transaction. It represents a set of security messages, exchanged between the transaction actors, guaranteeing several important security properties. Indeed, researchers in various studies, have analyzed the operation of this standard in order to verify its reliability: unfortunately, they have identified several security vulnerabilities that, today, represent major risks for our day to day safety. Consequently, in this thesis, we are interested in proposing new solutions that improve the reliability of this standard. In the first stage, we introduce an overview of the EMV security payment system and we survey its vulnerabilities identified in literature. In particular, there are two EMV security vulnerabilities that lead to dangerous risks threatening both clients and merchants: (1) the confidentiality of banking data is not guaranteed, (2) the authentication of the PoS is not ensured to the client’s device. Therefore, our interests move in the second stage to address these two weaknesses. We first review a selection of the related works that have been implemented to solve these vulnerabilities, and then, in order to obtain better results than the related works, we propose a new secure contact and NFC payment system that includes four innovative security mechanisms. Finally, in the third stage, we adapt our first security mechanism in the context of a new NFC payment architecture. This architecture is especially destined for small merchants, allowing them to take advantage of their NFC smartphones for use directly as NFC readers
Simatic, Michel. "Contributions au rendement des protocoles de diffusion à ordre total et aux réseaux tolérants aux délais à base de RFID." Phd thesis, Conservatoire national des arts et metiers - CNAM, 2012. http://tel.archives-ouvertes.fr/tel-00787598.
Full textSimatic, Michel. "Contributions au rendement des protocoles de diffusion à ordre total et aux réseaux tolérants aux délais à base de RFID." Electronic Thesis or Diss., Paris, CNAM, 2012. http://www.theses.fr/2012CNAM0823.
Full textIn asynchronous distributed systems, logical clock and vector clocks are two core tools to manage data communication and data sharing between entities of these systems. The goal of this PhD thesis is to exploit these tools with a coding viewpoint. In the first part of this thesis, we focus on data communication and contribute to the total order broadcast domain. We propose trains protocol: Tokens (called trains) rotate in parallel between participating processes distributed on a virtual ring. Each train contains a logical clock to recover lost train(s) in case of process(es) failure. We prove that trains protocol is a uniform and totally ordered broadcast protocol. Afterwards, we create a new metric: the throughput efficiency. With this metric, we are able to prove that, from a throughput point of view, trains protocol performs better than protocols presented in literature. Moreover, this metric gives the maximal theoretical throughput which can be reached when coding a given protocol. Thus, it is possible to evaluate the quality of the coding of a protocol. Thanks to its throughput performances, in particular for small messages, trains protocol is a remarkable candidate for data sharing between the cores of a processor. Moreover, thanks to its temperance concerning network usage, it can be worthwhile for data replication between servers in the cloud. Part of this work was implemented inside a control-command and supervision system deployed among several dozens of industrial sites. In the second part of this thesis, we focus on data sharing and contribute to RFID domain. We propose a distributed shared memory based on RFID tags. Thanks to this memory, we can avoid installing a computerized global network. This is possible because this memory uses vector clocks and relies on the network made by the mobile users of the distributed application. Thus, the users are able to read the contents of remote RFID tags. Our RFID-based distributed shared memory is an alternative to the three RFID-based architectures available in the literature. This distributed shared memory was implemented in a pervasive game tested by one thousand users
Roussafi, Abdellah. "Modélisation compacte du rayonnement d'antennes ULB en champ proche/champ lointain : mise en application en présence d'interface." Thesis, Université Côte d'Azur (ComUE), 2016. http://www.theses.fr/2016AZUR4137/document.
Full textUWB antennas bandwidth makes them highly suitable for a number of applications. In surface penetrating radar (SPR) applications, which is the focus of our research, such a bandwidth range allows good signal penetration ability and fine space resolution for microwave imaging. In addition, it has been shown that the knowledge of the radiated field by the antenna enhances drastically the quality of the resulting images. The work reported in this thesis deals with the problematic of the huge amount of data representing UWB antennas. Indeed, due to the frequency dependence, the classical antenna parameters are not sufficient to characterize this type of antenna. The scalar or vector spherical wave expansion is widely used to expand the radiation pattern of a radiating antenna and permit a high compression data rate. On the other hand, the Singularity Expansion Methods are used in frequency/time domain to model the antenna response by a set of resonant poles. The purpose of this thesis is to establish a compact model representing accurately the antenna radiation characteristics, which also allows to find the field at various distances. To this end, several ways of combining the aforementioned methods have been investigated. The proposed approach is validated by modeling the simulated and measured radiation pattern of an Exponential Tapered Slot Antenna (ETSA) in free space. Furthermore, we verify that the established compact model provide radiated field at different distances from the antenna with a compression of the initial pattern up to 99% and an error below 3%. The last part of this thesis, present an application of the proposed methodology to SPR context
Nguyen, Khoa-Van. "Technologie binaurale et contexte de réalité virtuelle : études perceptives et optimisation." Paris 6, 2012. http://www.theses.fr/2012PA066589.
Full textBinaural synthesis is a spatialization technique for headphone listening. It relies on the Head Related Transfer Functions (HRTFs) encoding the auditory space in a unique way for each individual and allows to virtually position an auditory source at any location in space. Binaural synthesis was developed and tested only considering the auditory perception. In this thesis, binaural synthesis is used in the context of virtual reality (VR) environments, involving other sensory modalities. Crossmodal perceptual effects arise and may improve or lower the feeling of presence, which is the aim of RV. We focus on two perceptual and technical aspects about the spatial coherence between the different modalities. First, binaural synthesis is associated with a visual stereoscopic rendering and we run perceptual experiments on visuo-auditory interactions. It is shown that VR gives results that are comparable to those obtained in real conditions. Then, we take advantage of the VR characteristics to use more complexe stimuli and vary the experimental conditions. Second, we explore a method to get a better distance synthesis, especially in near-field, with binaural technique. We use spherical acoustics to extrapolate measured HRTFs toward closer and further distances. This method is compared to other methods and is shown to get slightly better objective results
Hamzaoui, Mohammed. "Contribution à l'optimisation de balises de transmission voie-machine dans le domaine des transports guidés : étude du couplage d'antennes fonctionnant en champ proche." Lille 1, 1992. http://www.theses.fr/1992LIL10159.
Full textSingh, Parth Raj. "Source localization with MIMO systems." Thesis, Nantes, 2017. http://www.theses.fr/2017NANT4043/document.
Full textSources localization is used in radar, sonar, and telecommunication. Radar has numerous civilian and military applications. Radar system has gone through many developments over the last few decades and reached the latest version known as MIMO radar. A MIMO radar is composed of multiple transmitting and receiving antennas like a conventional phased array radar. However, its transmitting antennas transmit linearly independent signals so that they can be easily identified by the matched filters bank at its receiving end. The matched filtered signals are then processed to extract the ranges, DOAs, DODs, velocities, etc. of the targets. A bistatic MIMO radar system provides high resolution, spatial diversity, parameter identifiability, etc. which inspired us to use it in this work. There are many existing methods to deal with the far field region of MIMO radar system. However, little work can be found on the near field region of a bistatic MIMO radar which motivated the work in this thesis. Near field targets localization is also important because of many indoor applications. Most of the existing near field sources localization techniques use Fresnel approximation in which the real spherical wavefront is assumed quadric unlike planar in far field situation. In this work we have proposed a novel near field targets localization method using Fresnel approximation. The Fresnel approximation leads to a biased estimation of the location parameters because the true wavefront is spherical. Consequently, we have proposed two correction methods to reduce the effects of Fresnel approximation and other two methods which directly use the exact signal model based on spherical wavefront
Iliopoulos, Ioannis. "Engineering the near field of radiating systems at millimeter waves : from theory to applications." Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1S165.
Full textWith the demand for near-field antennas continuously growing, the antenna engineer is charged with the development of new concepts and design procedures for this regime. From the microwave and up to terahertz frequencies, a vast number of applications, especially in the biomedical domain, are in need for focused or shaped fields in the antenna proximity. This work proposes new theoretical methods for near-field shaping based on different optimization schemes. Continuous radiating planar apertures are optimized to radiate a near field with required characteristics. In particular, a versatile optimization technique based on the alternating projection scheme is proposed. It is demonstrated that, based on this scheme, it is feasible to achieve 3-D control of focal spots generated by planar apertures. Additionally, with the same setup, also the vectorial problem (shaping the norm of the field) is addressed. Convex optimization is additionally introduced for near-field shaping of continuous aperture sources. The capabilities of this scheme are demonstrated in the context of different shaping scenarios. Additionally, the discussion is extended to shaping the field in lossy stratified media, based on a spectral Green's functions approach. Besides, the biomedical applications of wireless power transfer to implants and breast cancer imaging are addressed. For the latter, an extensive study is included here, which delivers an outstanding improvement on the penetration depth at higher frequencies. The thesis is completed by several prototypes used for validation. Four different antennas have been designed, based either on the radial line slot array topology or on metasurfaces. The prototypes have been manufactured and measured, validating the overall approach of the thesis
El, Hatmi Fatiha. "Conception d'antennes de communication à travers le corps humain pour le suivi thérapeutique." Phd thesis, Université Paris-Est, 2013. http://tel.archives-ouvertes.fr/tel-00962121.
Full textArab, Salmanabadi Soodeh. "Mise en œuvre d'une unité sans fil de faible consommation pour la surveillance continue en santé." Master's thesis, Université Laval, 2017. http://hdl.handle.net/20.500.11794/27616.
Full textLalj, Hicham. "Conception et caractérisation de filtres et systèmes antennaires reconfigurables chargés par des résonateurs Métamateriaux sub-longueurs d’onde." Thesis, Rennes, INSA, 2014. http://www.theses.fr/2014ISAR0022/document.
Full textThe basic structures of metamaterial nourish a promising alternative technology, which aims to meet new demands of miniaturization and performance of reconfigurable radio systems. The work of this thesis based on the combination of miniature and agile cells, according to excitation conditions in the near-field electromagnetic, and a planar microwave devices to achieve a new structure of filters and reconfigurable antenna systems. After a presentation of the state of the art, on both the concept of metamaterial microwave and models of filters and antennas based on metamaterial, our work then propose four orientations. The first relates to the engineering design and simulation of electromagnetic metamaterial unit cells, and the study of miniaturization and agility of the electrical parameters. The second orientation is devoted to the realization of new models of filters based on loading the microstrip line with metamaterial resonators. Two filter models are developed and validated experimentally. The first concerns a band stop filter based on the combination of a microstrip line and SRR resonator. According to the same model, a band-pass filter based on a microstrip line associated with two cells in two different resonant frequencies is proposed. The second model provides a band stop filter based on a microstrip line loaded with CSRR cells, a study miniaturization of this model was presented and used both geometric and electrical optimization of parameters. The agility techniques studied are based on the loading of the cell by active electronic elements such as PIN and varactor diodes which are inserted in appropriate positions. The obtained results showed an interesting variation of the filter parameters. The third focus of the thesis is to introduce new models of association in the near-field, between UWB monopole antenna and metamaterial. The first model relates a monopole antenna associated with SRR cells printed in the substrate close to the excitation line of the antenna. The theoretical and experimental results confirm the behavior stop band around the cell resonance frequency, and a stable performance of radiation in the rest of the reference antenna bandwidth. For the second model the monopole is loaded by the SRRs CSRRs cells. After optimization of the cells excitation conditions, the simulation results confirm both the stop band behavior around the cell resonance frequency and the stability of the radiation pattern. The latest orientation concerns the realization of two new antenna systems with multi frequency constraints for cognitive radio application. The first system is based on a monopole antenna and tunable SRRs cells. The measurement and simulation results show a UWB behavior with two reconfigurable and controllable filtered bands. The second new systems tempt to reply the antennas systems requirements used in the cognitive radio. All results showed a flexibility of switching from antenna-sensor (ULB) to a communication antenna with tunable and controllable narrow band
Paković, Srdan. "Contributions to the theory of non diffractive waves and synthesis of metallic Bessel beam/X-wave launchers." Thesis, Rennes 1, 2021. http://www.theses.fr/2021REN1S128.
Full textThis thesis present the author’s contributions to the field of non-diffractive waves. Essentially, non-diffractive waves are electromagnetic beams that radiate localized energy with a variety of potential practical applications. The work presented in this thesis can be divided into two parts. In the first part, a novel concept of synthesizing metallic spline profiled Bessel beam/X-wave launchers has been proposed. First, an ad-hoc tool based on mode matching is presented. The tool is capable of evaluating the S parameters, near-, and far-field radiation patterns of metallic structures with azimuthal symmetry. Then, metallic Bessel beam/X-wave launchers are synthesized using the ad-hoc tool. The concept has been experimentally validated by manufacturing and measuring an X-wave launcher operating in a 75-105 GHz frequency range. The fabricated launcher is the first experimental demonstration of an X-wave launcher at such frequencies. In the second part, we have investigated the use of non-diffractive waves for wireless power transfer. First, the use of Bessel-Gauss beams for WPT is investigated. The superior performance of Bessel-Gauss beams compared to Bessel beams is demonstrated. A Bessel-Gauss launcher has been designed for validating this claim. The power transfer coefficient of the launcher exceeds 50% for distances exceeding its non-diffractive range
Avella, Castiblanco Jorge. "Electromagnetic modeling for antenna design and specifications in tunnels of arbitrary cross-section and answering to the electromagnetic constraints of the environment of the railway domain." Thesis, Lille 1, 2013. http://www.theses.fr/2013LIL10189.
Full textThis thesis aims to develop original and appropriate methodologies to model the propagation of EM waves in tunnels of any shape and to propose methodologies to optimize the specification, design and positioning of the antenna in the tunnel. We proposed a novel method for full-wave modal analysis to treat the case of EM wave propagation in structures of large electric dimensions or confined environments of any shape such as tunnels. This method is a modal approach which is based on the 2.5D TLM algorithm and Matrix Pencil algorithm for the discrimination of modes in lossy structures in which the modal density is high and the modes overlap. We considered new boundary conditions called SIBC (Surface Impedance Boundary Condition) for dielectric waveguides with losses. To analyze the general case and several realistic tunnel configurations, we proposed a new classification of modes. Indeed, the classification of existing methods is no longer applicable due to depolarization effects in some realistic cases. A new methodology for determining the specifications and positions of antennas in confined or guided structures was then developed. This methodology is based on a combination of modal analysis and optimization techniques to adjust the weights of the different modes in the tunnel. This approach is used in the case of adaptive antennas, but it has never been applied to the case of multipath propagation modes in the tunnel
Alimi, Vincent. "Contributions au déploiement des services mobiles et à l'analyse de la sécurité des transactions." Phd thesis, Caen, 2012. http://www.theses.fr/2012CAEN2061.
Full textElectronic transactions have paved the way for a multitude of services in various forms : a home banking web portal, an access control smart card opening a door or paying a transit fare, or an application downloaded onto a computer or a mobile device such a personal digital assistant or a mobile phone. The latter category of mobile equipment is extremely promising in terms of service offers. Indeed, a mobile handheld device is connected to the Internet with speeds higher and higher and is also more powerful. With the advent of the NFC (Near Field Communication) technology and secure architectures, mobile devices now has the ability to host sensitive applications in a secure chip, called « Secure Element ». Unlike plastic form factors, the Secure Element is a dynamic environment where you can download applications that will be accessible by a reader such as a point of sale or an access control reader. Those services are called mobile contactless services or NFC mobile services. We propose in this thesis several contributions to facilitate the deployment of mobile services based on a Secure Element. The adoption of this high added value services relies on an infrastructure and tools shared by different actors. As a first step, we propose three contributions to aid the deployment of mobile services Secure Element based allowing to: facilitate the personalization of a Secure Element by a TSM non-owner thereof, facilitate the exchange of keys for the TSM and perform a transaction with a mobile phone as a point of sale. In a second step, we focus on the analysis of payment transactions
Zheng, Tian. "Analyse de Fiabilité et de performance d'un Système de Véhicules Intelligents." Phd thesis, Ecole Centrale de Lille, 2013. http://tel.archives-ouvertes.fr/tel-00866223.
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