Dissertations / Theses on the topic 'Bande WiFi'

Les progrès récents dans le domaine des technologies biomédicales et de la santé connectée ont considérablement accéléré le développement de dispositifs flexibles et portables pour une surveillance continue de la santé. Le marché de l'Internet des Objets Médicaux (IoMT) devrait connaître une croissance rapide avec un taux annuel de 38.5% entre 2024 et 2032, largement porté par les Réseaux de Capteurs Corporels Sans Fil (WBAN). Cependant, la conception de dispositifs IoT portables, miniaturisés et biocompatibles, capables de fonctionner de manière autonome, reste un défi majeur, en particulier pour les capteurs physiologiques. Cette thèse propose le développement d’un système portable de récupération d'énergie sous la forme d’un dispositif appliqué sur la peau, destiné à la surveillance de l'état physiologique. L’un des principaux défis de ce travail réside dans l’impact du corps humain sur les performances des antennes, qui sont directement influencées lorsqu’elles sont positionnées sur la peau. Les Conducteurs Magnétiques Artificiels (AMC) apparaissent comme une solution prometteuse en tant que réflecteurs pour des antennes à faible profil fonctionnant dans les bandes GSM et WiFi. Grâce à leurs propriétés de réflexion à phase nulle, les AMCs permettent d’améliorer les performances des antennes tout en éliminant la nécessité d’un plan de masse volumineux de type quart d’onde. Les tests expérimentaux réalisés sur une antenne à double bande équipée d’un AMC ont démontré une distorsion minimale des performances pour les applications WBAN. Enfin, l’intégration d’un convertisseur RF-DC permet à la rectenna de fonctionner comme un collecteur d’énergie portable et autonome, tout en fournissant une tension redressée de 1V à environ -17.5 dBm, ce qui est suffisant pour alimenter certains capteurs physiologiques
Recent advancements in remote healthcare and biomedical technologies are rapidly accelerating the development of flexible, wearable devices for continuous health monitoring. The Internet of Medical Things (IoMT) market is projected to grow at a Compound Annual Growth Rate (CAGR) of 38.5% between 2024 and 2032, with Wireless Body Area Networks (WBAN) serving as a critical driver of this growth. Thus far, the expansion of IoT devices has faced challenges in designing wearable, miniaturized, and biocompatible prototypes with power-autonomous operation for physiological sensors. Therefore, this thesis aims to develop a wearable Energy-Harvesting (EH) system, in the form of a skin-applied device, designed for monitoring physiological conditions. The primary challenge of this research is the impact of the human body on the antenna system's performance when positioned directly on the skin. The body absorbs part of the radiation, which significantly reduces the efficiency of the EH system. In this context, Artificial Magnetic Conductors (AMC)s present a promising solution as reflectors for low-profile antennas, in the GSM and WiFi bands. By leveraging their inherent zero-phase reflection properties, AMCs improve antenna performance while eliminating the need for a bulky quarter-wave backplane. The real-world tests of the dual-band AMC-backed antenna showed minimal performance distortion for WBAN applications. Finally, the integration of a designed RF-to-DC converter enables the rectenna to function as an autonomous wearable energy harvester, providing a rectified voltage of 1V at approximately -17.5 dBm, suitable for powering certain physiological sensors

This master’s thesis is focused on the properties and types of helical antennas. The helical antenna work in the different modes. These modes are described in this thesis. There are also discussed possibility for design a dual-band helical antennas. The main aim of this work is the selection of a suitable solution and design a dual-band helical antenna for the WiFi band working at resonance frequencies of 2,4 GHz and 5 GHz. The simulation of this antenna was performed in the program CST Microwave studio.

La télémédecine et plus particulièrement la télémédecine mobile semble représenter l’avenir en termes de soins médicaux. Ce concept nécessite cependant pour sa viabilité, de disposer d’éléments rayonnants miniatures, fortement efficaces, et capables de communiquer sur plusieurs bandes. Ce mémoire présente la méthodologie de conception et l’optimisation d’antennes miniatures intégrées, dédiées à un dispositif spécifique permettant de réaliser une liaison radiofréquence entre un implant médical et le téléphone portable d’un patient. Cependant, la miniaturisation des antennes, éléments clés de ce concept, s’accompagne généralement d’une dégradation de son efficacité et de sa bande passante, ce qui rend délicat leur mise en œuvre sur au moins deux des points essentiels recherchés. La conception de ce type d'antennes nécessite donc une analyse très fine des phénomènes physiques mis en jeu dont notamment la limite théorique en termes de performances que l'on peut atteindre pour une antenne circonscrite à un volume donné. De plus, ces performances radioélectriques sont fortement dépendantes de l'environnement dans lequel est placée l’antenne. Par conséquent, l'influence de chaque partie constituant cet environnement doit être prise en compte lors de l'intégration, ce que nous décrivons également dans ce manuscrit à travers différentes solutions d’éléments rayonnants
This thesis presents the design and the optimization of miniature antennas integrated in specific devices dedicated to ensure communications between medical implants and a mobile phone in the context of telemedicine applications. However, the miniaturization of antennas necessarily implies a degradation of efficiency and bandwidth, which makes it difficult for implementation. Then, the design of electrically small antennas requires a very good understanding of the physical phenomena such as the theoretical limits of performance in terms of bandwidth and efficiency that can be expected for a radiating element with given dimensions. Furthermore, the performance of an electrically small antenna is also highly dependent on the environment in which it is mounted. Therefore, its interaction with each part of its close environment was highlighted and analyzed

L’ensemble des travaux présentés au sein de manuscrit porte sur la réalisation d’un synthétiseur de fréquences millimétriques capable de répondre aux besoins de la convergence WiFi-WiGig. Une première étude est réalisée dans le but de définir une architecture de synthétiseur de fréquence faible consommation adaptée aux standards du WiFi et du WiGig. L’ensemble des éléments composants la PLL sont par la suite détaillés, mettant en avant les avantages offerts par la technologie 28 nm FDSOI CMOS. Une étude plus approfondie des VCO millimétriques large bande et faible consommation est ensuite présentée, permettant de mettre en avant une réelle méthodologie de conception en lien avec la technologie 28 nm FDSOI CMOS. Finale-ment, diverses solutions sont proposées dans le but d’améliorer les performances de la PLL, avec l’incorporation de VCO millimétriques à ondes lentes, ou d’oscillateurs à anneaux synchronisés
The works presented in this manuscript focus on the realization of a millimeter frequency synthesizer meeting the needs of the WiGig-Fi convergence. A first study was conducted to define a suitable low-power frequency synthesizer archi-tecture for WiFi and WiGig standards. All of the PLL components are subsequently detailed, highlighting the 28nm CMOS FDSOI technology benefits. Then, a study of low power millimeter broadband VCO is presented, highlighting a design methodology related to the 28nm CMOS FDSOI technology. Finally, various solutions are proposed in order to improve the PLL performances, with the incorporation of slow wave VCO, or injection locked ring oscillators

En el presente proyecto de tesis se desarrolló el diseño para el mejoramiento de la Red WiFi de larga distancia del Napo, que fue implementada por el Grupo de Telecomunicaciones Rurales de la PUCP. Para lo cual, se evaluó el estado actual de la red y las limitaciones que esta presenta y de acuerdo a ello, se plantearon los requerimientos técnicos de la red, los cuales permitieron establecer los parámetros de diseño para la nueva red. Los problemas sobre la calidad de los servicios que brinda la red se presentan principalmente en los enlaces de backhaul, dado que no existe suficiente capacidad y por la ausencia de políticas de calidad de servicio. En esta tesis se desarrolló un nuevo diseño de los enlaces de backhaul de la Red del Napo; por lo cual, se evaluaron las distintas tecnologías recientes de banda ancha, asimismo los equipos disponibles en el mercado. Se eligió el equipo WiMAX Modelo LNK-LU150-N de la marca Albentia como la mejor opción; dicho equipo cumplió con los requerimientos técnicos planteados. Los enlaces del backhaul trabajarán en la frecuencia libre de 5.8 GHz con un ancho de banda de canal de 10MHz, y se utilizarán sistemas fotovoltaicos en las zonas donde no se dispone de energía eléctrica comercial para poder energizar los equipos. Asimismo, en esta tesis, se plantea un estudio de las diferentes políticas de calidad de servicio con la finalidad de cumplir los requisitos establecidos preliminarmente. Esto dio como resultado la selección de tipo de calidad de servicio Unsolicited Grant Service (UGS) para voz, Real-time Polling Service (rtPS) para vídeo y Best Effort (BE) para datos. Luego, se presentó la propuesta económica de la implementación de la nueva red. El resultado principal del presente trabajo es una propuesta de ampliación de la capacidad de la red y el establecimiento de políticas de calidad de servicio en el backhaul, lo cual permitiría mejorar los servicios de voz, datos y vídeo que utiliza los centros de salud que son interconectados por la Red del Napo.
Tesis

This master's thesis compares wireless technologies which they are used at current time. The most of information in this thesis are obtained from my practical experiences with design and realization of wireless network during last four years. The thesis briefly describes standards and security of WiFi. More time is devoted to the description of new standard 802.11n and the E-Band. The use of E-Band is allowed in Czech Republic from a year 2008. The thesis describes a practical evaluation of wireless network 802.11a/b/g/n and E-Band. Examples of the use are described in case studies of high-speed point-to-point wireless bridge, coverage of a logistic warehouse and wireless network with location in a hospital.

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Digital Inclusion is currently a concerning subject especially in those urgent countries. In Brazil there have been various initiatives and experiences regarding this subject, both from government parts (Federal, State and Urban) and through Non-Profitable Organizations and private companies. The approach to low-cost Broadband Internet has been one of the main barriers to the effectiveness on these initiatives. The goal of this current work is to find new concepts and connection management and voice services, data and video (triple play) in a unique wireless connection focusing on digital inclusion. The used wireless technology is the World Interoperability for Microwave Access (WiMAX), whose frequency is of 5,8 GHZ, which permission is not required for its usage along with National Telecommunication Agency (ANATEL) and to the access point, the wireless fidelity technology (Wifi). Some main convergent WiMAX technology characteristics are described in this work with new Triple Play services to hold a multipoint-point enlacement, causing an establishment to link a case study between the School and PUC-Campinas in order to investigate the performance and application factors. The results on the efficiency of metropolitan wireless network (WMAN) as well as the Triple Play services were profitable, defining a new method on prediction of coverage area and user s quantity.
Inclus?o Digital ? hoje um tema de muita preocupa??o, principalmente nos pa?ses denominados emergentes. No Brasil existem diversas iniciativas e experi?ncias relativas a esse assunto, tanto por parte dos governos (Federal, Estadual e Municipal), como tamb?m por parte de ONG s e empresas privadas. O acesso ? Internet Banda Larga a baixo custo tem sido uma das principais barreiras para a efetiva??o dessas iniciativas. O prop?sito do presente trabalho ? definir novos conceitos e par?metros de conex?o e servi?os de voz, dados e v?deo (triple play) em uma ?nica conex?o sem fio com foco na inclus?o digital. A tecnologia de conex?o sem fio (wireless) utilizada ? o World Interoperability for Microwave Acess (WiMAX), de freq??ncia 5.8 GHz, que n?o requer licenciamento para a sua utiliza??o junto a Ag?ncia Nacional de Telecomunica??es (ANATEL) e para o ponto de acesso, a tecnologia wireless fidelity (WiFi). Neste trabalho est?o descritas as principais caracter?sticas da tecnologia WiMAX convergentes, com os novos servi?os Triple Play para a realiza??o de um enlace ponto-multiponto, estabelecendo-se um link para estudo de caso entre a Escola e a PUC-Campinas, para a investiga??o dos fatores de desempenho e aplica??es. Os resultados de efici?ncia da rede sem fio metropolitana (WMAN) com os servi?os Triple Play foram satisfat?rios, definindo-se um novo m?todo de predi??o da ?rea de cobertura e do n?mero de usu?rios.

A interferência espectral gera patologias nos sistemas de comunicação sem fio (wireless), como por exemplo, quedas na comunicação e degradação na vazão. O espectro de RF (rádio frequência) é fiscalizado e controlado por órgãos governamentais, no entanto as redes sem fio padrão IEEE 802.11, conhecidas por WLANs (Wireless Local Area Networks), trabalham em faixas espectrais não licenciadas, conhecidas por ISM. Estas redes estão cada vez mais presentes nos ambientes comerciais e residenciais, contribuindo para questões de ubiquidade e acesso à Internet. Com este aumento expressivo, a cobertura espectral está cada vez mais densa. A densidade elevada de sinais aponta para a saturação do espectro ISM, causando interferências mútuas das redes IEEE 802.11. O objetivo deste trabalho é analisar a cobertura do espectro, por redes WLANs, e avaliar quedas de vazão ocasionadas por interferências espectrais, variando no espaço e no tempo. Dois cenários foram mapeados para analisar as degradações, um com baixa a média e outro com alta densidade e complexidade. O objetivo da criação desses cenários foi comparar as degradações causadas pelas interferências em ambientes diferentes, na ocupação, na utilização e na propagação de sinais de redes WLANs. Através dos resultados obtidos, um ciclo de vida de gerenciamento do espectro de redes padrão 802.11 foi proposto. Este ciclo contribui para avaliar e classificar o estado de uma rede em densa, não densa, complexa e não complexa, visto que alterações de ocupação do espectro no espaço e no tempo são plausíveis de ocorrerem. Conclui-se que os impactos da sobreposição total do canal, por fontes 802.11, não são suficientes para a substancial degradação da vazão em ambientes de baixa a média complexidade. Em ambientes com alta densidade e complexidade as degradações são mais evidentes, principalmente quando ocorrem perturbações vindas de duas fontes adjacentes
The spectral interference generates pathologies in wireless communication systems (wireless), such as declines in communication and degradation in flow. The spectrum of RF (radio frequency) is supervised and controlled by government agencies, however the wireless standard IEEE 802.11, known as WLANs (Wireless Local Area Networks), work in unlicensed spectrum bands, known as ISM. These networks are increasingly involved in commercial and residential environments, contributing to issues and ubiquity of Internet access. With the significant increase in these networks, the spectral coverage is increasingly dense. The high density of signals pointing to the saturation of the ISM spectrum, causing mutual interference of IEEE 802.11 networks. The aim of this study is to analyze the coverage of the spectrum, for WLANs, and evaluate the flow falls caused by spectral interferences, varying in space and time. Two scenarios were mapped to examine the degradations, with a low to medium and one with high density and complexity. The purpose of creating these scenarios was to compare the degradation caused by interference in different environments, occupation, use and spread of signals WLANs. Through the results, a life cycle management of the spectrum of standard 802.11 networks was proposed. This cycle helps to evaluate and classify the state of a dense network, not dense, complex and not complex, since changes in occupation of the spectrum - in space and time - are plausible to occur. It is concluded that the impacts of the complete overlap of the channel, sources 802.11, are not sufficient to the substantial degradation of the flow in low to medium complexity. In environments with high density and complexity of the degradation is more evident, especially when there are disturbances coming from two adjacent sources

Vehicular communications are a major subject of research and policy activity in industry, government, and academia. Dedicated Short-Range Communications (DSRC) is currently the main protocol used for vehicular communications, and it operates in the 5.9 GHz band. In addition to DSRC radios, other potential uses of this band include Wi-Fi, LTE-V, and communication among unlicensed devices. This dissertation presents an architecture and a feasibility analysis including field measurements and analysis for vehicle-to-train (V2T) communications, a safety-critical vehicular communication application. The dissertation also presents a survey of research relevant to each of several possible combinations of radio-spectrum and vehicular-safety regulations that would affect use of the 5.9 GHz band, identifies the most challenging of the possible resulting technical challenges, and presents initial measurements to assess feasibility of sharing the band by DSRC radios and other devices that operate on adjacent frequencies using different wireless communication standards. Although wireless technology is available for safety-critical communications, few applications have been developed to improve railroad crossing safety. A V2T communication system for a safety warning application with DSRC radios can address the need to prevent collisions between trains and vehicles. The dissertation presents a V2T early warning application architecture with a safety notification time and distance. We conducted channel measurements at a 5.86�"5.91-GHz frequency and 5.9-GHz DSRC performance measurements at railroad crossings in open spaces, shadowed environments, and rural and suburban environments related to the presented V2T architecture. Our measurements and analyses show that the DSRC protocol can be adapted to serve the purpose of a V2T safety warning system. The 5.9 GHz band has been sought after by several stakeholders, including traditional mobile operators, DSRC proponents, unlicensed Wi-Fi proponents and Cellular-Vehicle-to-Everything (C-V2X) proponents. The FCC and National Highway Traffic Safety Administration (NHTSA), the two major organizations that are responsible for regulations related to vehicular communications, have not finalized rules regarding this band. The relative merits of the above mentioned wireless communication standards and coexistence issues between these standards are complex. There has been considerable research devoted to understanding the performance of these standards, but in some instances there are gaps in needed research. We have analyzed regulation scenarios that FCC and NHTSA are likely to consider and have identified the technical challenges associated with these potential regulatory scenarios. The technical challenges are presented and for each a survey of relevant technical literature is presented. In our opinion for the most challenging technical requirements that could be mandated by new regulations are interoperability between DSRC and C-V2X and the ability to detect either adjacent channel or co-channel coexisting interference. We conducted initial measurements to evaluate the feasibility of adjacent channel coexistence between DSRC, Wi-Fi, and C-V2X, which is one of the possible regulatory scenarios. We set DSRC at Channel 172, Wi-Fi at Channel 169 for 20 MHz bandwidth and at Channel 167 for 40 MHz, and C-V2X at Channel 174 with almost 100% spectrum capacity. From the measurements, we observed almost no effects on DSRC performance due to adjacent channel interference. Based on our results, we concluded that adjacent channel coexistence between DSRC, C-V2X, and Wi-Fi is possible. DSRC systems can provide good communication range; however, the range is likely to be reduced in the presence of interference and / or Non-Line-of-Sight (NLoS) conditions. Such environmental factors are the major influence on DSRC performance. By knowing the relationship between DSRC and environmental factors, DSRC radios can be set up in a way that promotes good performance in an environment of interest. We chose propagation channel characteristics to generate DSRC performance modelling by using estimation methods. The conducted DSRC performance measurements and propagation channel characteristics are independent; however, they share the same distance parameters. Results of linear regression to analyze the relationship between DSRC performance and propagation channel characteristics indicate that additional V2T measurements are required to provide data for more precise modeling.
PHD

Située au contact entre la plaque australienne et l'arc de Banda, l'ile de Timor, est classiquement considérée comme une chaine issue d'un modèle géodynamique de subduction/collision. Cette ile constituait la bordure septentrionale de la marge passive australienne avant d'être incorporée au fore-arc de Banda. Pour comprendre ce mécanisme tectonique nous avons réalisé un transect tectonique qui recoupe toutes les structures du nord au sud. Les recherches ont porté essentiellement sur l'établissement d'une échelle lithostratigraphique et sur l'étude de la déformation des séries rencontrées le long de ce transect. Structuralement, on distingue : des séries para-autochtones qui constituent en fait le substratum visible de l'ile du permien à l'Éocène au nord aussi bien qu'au sud, des séries allochtones (Jurassique à Éocène) localisées principalement au nord et mises en place pendant la phase tectonique paroxysmale (Oligocène) et des formations autochtones déposées postérieurement à la mise en place des nappes allochtones et dont les âges vont du Miocène inférieur à l'actuel. L'un des buts de l'étude lithostratigraphique était d'établir une succession avec des facies caractéristiques pouvant servir de niveaux repère pour la cartographie et la tectonique. Ces successions (formations) ont été calés dans le temps grâce à 40 nouvelles datations et grâce aux comparaisons avec les travaux antérieurs. Nous avons distingué 9 formations (de a à i) dans les séries para-autochtones, 4 formations dans les séries allochtones et, dans les séries autochtones nous avons individualisé 3 formations dans la partie nord et 4 dans la partie sud. L'étude de la déformation à l'échelle de l'affleurement aussi bien qu'à l'échelle du transect régional, montre que toutes les séries y compris d'ailleurs les séries du Miocène sont plissées et écaillées. Cette structuration de type imbriquée intéresse des séries continues si bien que l'existence d'une structure de type mélange tectonique à l'échelle de l'ile n'a pu être démontrée le long de ce transect. Les comparaisons entre les études structurales et les données stratigraphiques montrent l'existence de deux phases principales dans la structuration de l'ile ; une phase ante-Miocène qui correspond probablement à la mise en place des nappes allochtone et une phase d'écaillage intense située à la limite Pliocène inférieur-Pliocène moyen. Ces travaux constituent un stade obligatoire pour l'établissement d'un modèle géodynamique tenant compte à la fois de l'évolution de la marge passive australienne et de la mer de Banda, avant l'apparition de l'arc volcanique de Banda, à la fin du Miocène

Le brouillard électromagnétique dans lequel nous vivons en permanence estaujourd’hui montré du doigt car, outre les risques sanitaires qu’il pourrait engendrer, illimite l’usage de certaines technologies. L’importance des interférences entre réseauxsans fil, ou la peur du piratage sur ces mêmes réseaux, en sont deux exemples. Cetravail de thèse vise à développer un nouveau moyen de protection contre certaines deces ondes électromagnétiques. Plus spécifiquement, ce travail se focalise sur unetechnologie capable de filtrer uniquement les ondes WiFi et GSM à travers de grandessurfaces d’une habitation, comme un mur. Pour ce faire, la fonctionnalisation d’uncomposant standard des bâtiments, le papier-peint, a été étudié.L’utilisation de surfaces sélectives en fréquence a été retenue. Ces motifs sontdirectement imprimés sur du papier à l’aide d’encre conductrice et de la techniqued’impression flexographique. L’étude s’est également portée sur la réalisation de motifsde filtrage innovants. Les résultats de simulation montrent qu’ils sont capables de filtrerdeux ou trois bandes, qu’ils sont quasiment insensibles à la polarisation et à l’angled’incidence dans une plage allant de 0° à ± 80°. Le travail a ensuite permis dedémontrer la faisabilité pratique de ce concept aux stades laboratoire et industriel.Ensuite, nous avons démontré expérimentalement l’efficacité de ce concept dans lesbandes WiFi. La transmission atteint alors -30 dB. Enfin, une validation expérimentaledu produit en situation réelle a été menée, à savoir la pose du papier-peint sur du plâtre,du bois, l’influence de la colle ou encore la pose d’une couche de papier-peint décoratifpar-dessus le produit.En conclusion, les résultats pratiques obtenus confirment les résultats théoriquesestimés et, permettent à ce nouveau concept, appelé métapapier, d’être suffisammentefficace pour permettre la réduction des ondes WiFi ou GSM
The electromagnetic smog in which we live today is nowadays a real issue because it limits the use of certain technologies and also because there are some potential health risks associated with it, even if the latter is still a controversial subject. The importance of the interferences between wireless networks or the possibility of data hacking on the same networks are two examples. The aim of this thesis is to develop a new way to protect buildings against some of these electromagnetic waves. More specifically, this work focuses on a technology able to filter only the WiFi and the GSM waves through large areas of a home, like a wall for example. To do this, the functionalization of a standard component of buildings, the wallpaper, was studied. The use of frequency selective surface (FSS) was chosen. These patterns are printed directly on paper with a conductive ink printing technology: the flexography. The study also focuses on the realization of innovative filter designs. Simulation results show that these novel FSS are able to filter two or three bands. They are almost insensitive to the polarization and to the angle of incidence in the range of 0° to ±80°. The realization feasibility of this concept in a laboratory or in industrial conditions was demonstrated. Next, an experimental demonstration of this concept in the WiFi bands was carried out. In this context, the transmission coefficient was reached -30 dB. Finally, an experimental validation of the product in real conditions of use was conducted, namely the wallpaper was put over plasterboards or over wood panels. Also, the influence of the glue on the general performances and the placement of a decorative wallpaper over the FSS wallpaper were studied. In conclusion, the practical results obtained confirm and validate the theoretical predictions of this new concept, called metapaper, and show that the practical realizations are efficient enough to allow the reduction of WiFi or GSM signals

This thesis is concerned the technology with technologies of transfer through wireless devices. It is about possibilities of optimization of transfer in wireless net, especially of the reduction of interference influence. The first part is about theory and the standards development of wireless technology. There are methods and principles used in wireless technologies. The second part is a practical measuring and testing of an internal wireless net, with the emphasis being on the source of interference influence. Measuring was focused on interference between access points and was not about meteorological influence. It continues with theory and testing of interference of the microwave oven in our wireless net. Then, it is a practical demonstration of interference in an external environment. There are practical examples of interference between different providers’ nets on the same area and solutions to prevent or to cancel this interference. In next part of work the wireless net is parsed and described in a given territory. Here is described the way how to precede the reciprocal interference and eventually how this mutual disturbance suppress. Consequently, our net is optimized for customer growth and for today’s options of newer and more powerful components for wireless transfer. Finally there are two laboratory tasks. The first one is about practical measuring and testing of wireless net’s parameters and the second one is about simulation of wireless networks in the Opnet program.

碩士
元智大學
通訊工程學系
95
This thesis presents a design of the modified bow-tie slot antenna fed by CPW for WiMAX systems, and then extends this antenna to the dual-band operation for both WiMAX and WiFi applications. For the automotive environments of wireless usages, the bow-tie slot active antenna is presented with the integrations of the proposed antenna and the low noise amplifier for improving the receive noise figure. The influences of the antenna performances for integrating the active device are also examined.

碩士
景文科技大學
電腦與通訊研究所
101
In this thesis, the miniaturization of LTE / WiFi full-band antenna to conform to the world. Frequency range from LTE lower band frequency from 698MHz to 960MHz and LTE upper band frequency from 1710MHz to 2700MHz and WiFi 5G (5150MHz to 5850MHz). In this paper the antenna used asymmetric dipole antenna infrastructure and feed is using the coplanar waveguide in order to improve the bandwidth of a dipole antenna The center conductor is designing of upper band frequency 1710MHz of λ/ 4. And ground line is designing of lower band frequency 698MHz of λ/ 4. Proposed four kinds of optimized design, top loadind, spiral structure, feed of stepped and meander line makes the frequency band as well as frequency bandwidth be able to in full compliance with the all frequency bands of covered by by the LTE as well as WiFi. The experimental results of the constructed prototype are presented.

Dissertação apresentada à Universidade de Trás-os-Montes e Alto Douro para obtenção do grau de Mestre em Informática, orientada por Vítor Manuel de Jesus Filipe e António Manuel de Jesus Pereira.
Actualmente, devido a questões de índole financeira, as operadoras de acesso à Internet não investem em zonas rurais porque não existe compensação financeira adequada ao investimento, nem uma solução tecnicamente válida. Este facto origina cada vez mais o aparecimento das designadas redes WBL (Wireless Banda Larga), que permitem fornecer acesso à Internet às populações discriminadas por esta circunstância. Os aspectos relacionados com a gestão destas redes são normalmente esquecidos e actualmente existe uma carência de soluções economicamente viáveis que possam auxiliar com eficiência esta função. Após uma pesquisa intensiva de soluções comerciais e opensource, de gestão de redes WBL, verificou-se a inexistência de uma solução economicamente viável, assim como, a ausência de um modelo de gestão para as zonas rurais. Este trabalho contribui para a definição de um modelo de gestão, assim como para parte da sua implementação. A proposta do modelo assenta numa solução centralizada, que congrega várias módulos de software opensource, capazes de responder ao conjunto de funcionalidades identificadas como essenciais ao modelo. Os testes efectuados mostram que o modelo apresentado representa uma solução completa, capaz de abranger as várias áreas do processo de gestão de redes WBL em zonas rurais.

Dissertação de Mestrado em Informática
Actualmente, devido a questões de índole financeiras, as operadoras de acesso à Internet não investem em zonas rurais porque não existe compensação financeira adequada ao investimento, nem uma solução tecnicamente válida. Este facto origina cada vez mais o aparecimento das designadas redes WBL (Wireless Banda Larga), que permitem fornecer acesso à Internet às populações discriminadas por esta circunstância. Os aspectos relacionados com a gestão destas redes são normalmente esquecidos e actualmente existe uma carência de soluções economicamente viáveis que possam auxiliar com eficiência esta função. Após uma pesquisa intensiva de soluções comerciais e opensource, de gestão de redes WBL, verificou-se a inexistência de uma solução economicamente viável, assim como, a ausência de um modelo de gestão para as zonas rurais. Este trabalho contribui para a definição de um modelo de gestão, assim como para parte da sua implementação. A proposta do modelo assenta numa solução centralizada, que congrega várias módulos de software opensource, capazes de responder ao conjunto de funcionalidades identificadas como essenciais ao modelo. Os testes efectuados mostram que o modelo apresentado representa uma solução completa, capaz de abranger as várias áreas do processo de gestão de redes WBL em zonas rurais.
Currently, due to questions of financial order, the Internet Service Providers do not invest in rural zones, because the investment is not profitable, and technologically doesn’t exist a model definition. This fact originates more and more the appearance of the calls WBN (Wire-less Broadband Networks), that are going to supply access to the Internet to populations discriminated by this circunstance. The aspects related with the management of these networks are normally forgetful and currently exists a lack of economically and technical viable solutions, that be able to help with efficiency this function. After an intensive research of commercial and opensource solutions to management the wire-less networks, it was verified the absence of an economically viable solution as well as the absence of a model of management for the WBN in rural zones. This article contributes to the definition of a management model of these networks. The proposal model settles in a centralized solution, that congregates several modules of opensource software, able to respond to the range of essential features identified in the model. The tests show that the model presented, represents a complete solution, able to cover several areas of the process of WBL management.

碩士
國立交通大學
電信工程研究所
107
Currently, the gateways on the market are mainly products with WIFI communication function. WIFI uses two major frequency bands of 2.45GHz and 5.5GHz. With the rise of the Internet of Things, NB-IoT communication function is going to be combined. The frequency bands used by NB-IoT communication function are 700MHz, 900MHz, 1800MHz, of which 700MHz corresponds to the longest wavelength, the design area is the most difficult to be miniaturized. This paper presents an Aperture-coupled miniaturized multi-band patch antenna. This design can be used in the communication applications of gateways in the future for WIFI and Internet of Things. The requirements include multi-band, omnidirectional radiation pattern, high gain, area miniaturization design and high isolation. However, the traditional monopole antenna and PIFA antenna can not meet the requirements of both omnidirectional and high gain. Therefore, the design of this paper is based on the microstrip patch antenna. Firstly, the aperture coupled feed method is used to match the H-shaped radiator. Reducing the area of the 700MHz radiator and providing a wider bandwidth than the antenna fed by the traditional microstrip line, and then placing the high-band radiator into the low-band antenna through the concept of shared-aperture. In the groove, the coupling of the slot holes is perpendicular to the polarization direction, which narrows the distance between the radiators in each frequency band and reduces the coupling degree between the antennas. This method achieves the trade-off between cost reduction and area miniaturization and high isolation. And then fed into the matching circuit design combined with the transmission line theory and the filter principle, and further solved the problem of mutual interference between frequency bands. Finally, the physical field measurement is used to verify that the antenna has multi-band, high gain, small area and high isolation. In this paper, the multi-band antenna is integrated with the antenna size , the thickness is 4mm，working frequency726-783MHz, 2.36-2.6GHz and 4.96-6.1GHz, which is a three-layer board structure, using FR4 substrate, which is lower in cost and simple than the previous antenna manufacturing. In this paper, the antennas have 1.5dB, 3.2dB and 4.85dB gains in each of the three frequency bands, and the mutual coupling between the antennas is below -46dB, which enables them to have excellent radiation performance in each frequency band after miniaturization. To meet the needs of gateway antennas in future IoT and WIFI applications.

The electromagnetic wave absorption characteristics of composite cement-based building material have attracted much interest in recent times. Researchers have mainly focused on the 2 GHz to 12 GHz frequency range. Mobile and wireless communication systems use frequencies from 800 MHz upwards. The determination of characteristics such as reflection loss, absorption, attenuation and shielding effectiveness are crucial in the evaluation and development of these materials for the building industry. Absorption is an indication of how much of the EMW energy enters the material. Attenuation indicates how much of the absorbed energy is converted into other forms of energy by the material. Shielding effectiveness (SE) is a combination of reflection loss, attenuation and multiple internal reflections and attenuations. This research determined these characteristics by measuring the S11 and S21 parameters of the composite cement-based material in the GSM and WiFi frequency bands. The time domain gating function of a vector network analyser is applied to measure the reflection from the material. The data was then used to obtain the reflection and absorption losses in the frequency bands. The transmission loss was measured by placing the sample in the propagation path between two antennas. MnZn-ferrite and electrolytic manganese dioxide in powder form were evaluated as absorber material to increase the permeability of the cement-based material to improve absorption and attenuation capabilities to create a cost-effective practical electromagnetic wave absorber. The compound of the cement-based material was cement, sifted river sand and filler powder. The results achieved in the research showed the uniqueness of electrolytic manganese dioxide as filler in composite cement based material for electromagnetic wave shielding effectiveness improvement. The combined measurement techniques used in this research were uniquely used to determine the required electromagnetic wave absorption characteristics and shielding effectiveness of 10 dB was measured in the GSM850 and GSM900 frequency bands.
Dissertation (MEng)--University of Pretoria, 2013.
gm2014
Electrical, Electronic and Computer Engineering
unrestricted