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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

Entwicklung, Modellierung und Verifikation einer Dual-Feed-Antennenstruktur für leistungsfähige, passive UHF-RFID-Sensoren auf kritischen Oberflächen

Flieger, Matthias Ludwig 13 August 2013 (has links)
Die Weiterentwicklung klassischer, elektronischer Identifikationstechnologien leistet einen wichtigen Beitrag zum technischen Fortschritt in Industrie, Logistik und Gesundheitswesen. Die vorliegende Dissertationsschrift beschreibt die Entwicklung eines Dual-Feed-Antennendesigns für passive UHF-RFID-Transponder auf kritischen Oberflächen. Die zu Grunde liegende Antennenstruktur besteht aus einem Microstrip-Patch unter Verwendung eines verlustarmen Substratmaterials. Dieser erfährt eine Optimierung hinsichtlich seiner Lesereichweite, insbesondere auf kritischen Oberflächen. Ein Zwei-Port-Konzept mit gekoppeltem Feed-Line-Anpassnetzwerk reduziert die Anzahl benötigter, diskreter Komponenten und ermöglicht eine kostengünstige Herstellung mittels klassischer Ätzverfahren. Verschiedene Ansätze zur Modellierung und zur analytischen Berechnung der Antennenparameter werden dargestellt. Des Weiteren erfolgt eine Verifikation der Antennenstruktur anhand eines Konzepts für einen passiven Energy-Harvesting-RFID-Transponder, der zur Temperaturüberwachung in den genannten Branchen eingesetzt werden kann. Dieses Konzept schließt ein effizientes Energiemanagement mittels eines Ultra-Low-Power-Mikrocontrollers sowie Ansätze zur Energiegewinnung und -speicherung mit ein und stellt die Wahl wichtiger Systemparameter und Bauelemente anhand anwendungsspezifischer Abschätzungen dar.
132

Evaluation and Justification of an RFID Implementation : Pilot at IKEA Customer Distribution Centre

Larsson, Björn, Qviberg, Ola January 2004 (has links)
<p>The purpose of this final thesis isto develop a model for justification and evaluation of RFID technology. RFID is a new, relatively untested, technology using radio signals for automatic identification of different objects. Our theoretical frame of references focuses on research about RFID and implementation iss ues, we also conducted case studies and interviews in order to learn about RFID. Most RFID installations of today are Pilots or early adopters wanting to try new technology. A lot of the written sources were reports from consultancy firms or suppliers of technology. </p><p>Implementing RFID in real environment gave important insights into potentials and limitations of the technology. It proved that it is difficult to achieve sufficient readability in a steel environment. We also learned that one should not underestimate the time for installation and tuning in order to meet higher readability. The project finally resulted in an iterative model for justification and evaluation of RFID technology.</p>
133

Evaluation and Justification of an RFID Implementation : Pilot at IKEA Customer Distribution Centre

Larsson, Björn, Qviberg, Ola January 2004 (has links)
The purpose of this final thesis isto develop a model for justification and evaluation of RFID technology. RFID is a new, relatively untested, technology using radio signals for automatic identification of different objects. Our theoretical frame of references focuses on research about RFID and implementation iss ues, we also conducted case studies and interviews in order to learn about RFID. Most RFID installations of today are Pilots or early adopters wanting to try new technology. A lot of the written sources were reports from consultancy firms or suppliers of technology. Implementing RFID in real environment gave important insights into potentials and limitations of the technology. It proved that it is difficult to achieve sufficient readability in a steel environment. We also learned that one should not underestimate the time for installation and tuning in order to meet higher readability. The project finally resulted in an iterative model for justification and evaluation of RFID technology.
134

Analysis of technology and business antecedents for spectrum sharing in mobile broadband networks

Yrjölä, S. (Seppo) 21 March 2017 (has links)
Abstract Sharing is emerging as one of the megatrends influencing future business opportunities, and wireless communications is no exception to this development. Future mobile broadband networks will operate on different types of spectrum bands including shared spectrum, which calls for changes in the operation and management of the networks. The creation and capture of value by the different players in the mobile broadband ecosystem is expected to change due to regulation, technology, and business landscape related drivers that concern not only spectrum sharing, but also sharing of other resources such as infrastructure, technologies, or data. This thesis examines the key business and technology enablers needed to exploit spectrum sharing in mobile broadband networks, and presents the business model characteristics and strategic choices that spectrum sharing concepts support. Action research and integral scenarios methodologies were applied for strategic and business analysis utilizing the capacity and expertise of the policy, business and technology research communities. The thesis introduces a new approach to analyze the scalability of the spectrum sharing concepts and their business model elements utilizing sharing economy antecedent factors. The results indicate that all analyzed sharing concepts meet basic requirements to scale. The Licensed Shared Access (LSA) leverages existing assets and capabilities of the mobile network operator domain, the Citizens Broadband Radio Service (CBRS) extends the business model dynamics from connectivity to content, context and commerce, and the hybrid usage of Ultra High Frequency (UHF) band by Digital Terrestrial TV (DTT) and downlink Long Term Evolution (LTE) (HUHF) enables new collaborative opportunities between converging communication, Internet and media domains. The thesis validates the feasibility of spectrum sharing between mobile broadband networks and other types of incumbent spectrum users utilizing Finnish cognitive radio field trial environment (CORE), and expands the notion of spectrum sharing beyond the mobile broadband domain to be applied to other wireless systems including the media and broadcasting. The presented results can be used in developing the future mobile broadband systems enhanced with innovative spectrum sharing enabled business models to cope with the growing demand for capacity and new services by humans and machines. / Tiivistelmä Jakamistalous on yksi suurista tulevaisuuden liiketoimintamahdollisuuksiin vaikuttavista trendeistä, eikä langaton tietoliikenne ole tässä poikkeus. Tulevaisuuden laajakaistaiset matkapuhelinverkot tulevat hyödyntämään erityyppisiä radiotaajuuksia, kuten jaettuja taajuuskaistoja, mikä vaatii muutoksia verkkojen toimintoihin ja hallintaan. Eri toimijoiden arvonluonti- ja ansaintamahdollisuuksien odotetaan muuttuvan näissä liikkuvan laajakaistan ekosysteemeissä regulaation, teknologian ja liiketoimintaympäristön kehittyessä, ei vain taajuuksien jakamisessa, vaan myös kun kyseessä on muiden resurssien kuten infrastruktuurin, teknologioiden tai tiedon jakaminen. Väitöskirja tutkii teknologia- ja liiketoimintaedellytyksiä taajuusjakomenetelmille matkapuhelinverkoissa, sekä esittelee ja analysoi menetelmien mahdollistamia liiketoimintamalleja ja strategisia valintoja. Strategia- ja liiketoiminta-analyyseissä käytettiin toimintatutkimus- ja skenaariomenetelmiä poikkitieteellisissä tutkimusprojekteissa yhteistyössä reguloinnin, liiketoiminnan ja tekniikan tutkimusyhteisöjen kanssa. Tutkimus esittelee uuden lähestymistavan taajuusjakotekniikoiden liiketoimintamallien skaalautuvuuden analysointiin jakamistalouden määritelmiä hyödyntäen. Tulokset osoittavat, että kaikki tutkitut tekniikat täyttävät perusedellytykset skaalautuvuudelle; Licensed Shared Access (LSA) hyödyntäen matkapuhelinoperaattorin olemassa olevia resursseja ja kyvykkyyksiä, Citizens Broadband Radio Service (CBRS) laajentaen liiketoimintamalleja tietoliikenteestä sisältöön, kontekstiin ja kaupankäyntialustoihin, sekä digitaalitelevision ja langattoman LTE-tekniikan hybridikäyttö UHF-taajuuskaistalla (HUHF) mahdollistaen uusia liiketoimintamahdollisuuksia lähentyvien tietoliikenne-, Internet- ja mediaekosysteemien välillä. Väitöskirja tulokset vahvistivat taajuuden jakamisen soveltuvuuden liikkuvan laajakaistaverkon ja saman taajuusalueen eri teollisuudenalan haltijan välillä suomalaisessa CORE kenttätestausympäristössä, ja laajensivat taajuusjakotekniikan sovellettavuutta myös muihin langattomiin järjestelmiin sisältö- ja mediajakelussa. Esitettyjä tuloksia voidaan hyödyntää tulevaisuuden langattomien laajakaistaverkkojen kehitystyössä vastaamaan ihmisten ja koneiden kasvaviin tietoliikennepalveluiden ja -kapasiteetin tarpeisiin hyödyntäen tehokkaita taajuusjakotekniikoita ja niiden mahdollistamia innovatiivisia liiketoimintamalleja.
135

Front-end considerations for next generation communication receivers

Roy, Mousumi January 2011 (has links)
The ever increasing diversity in communication systems has created a demand for constant improvements in receiver components. This thesis describes the design and characterisation of front-end receiver components for various challenging applications, including characterisation of low noise foundry processes, LNA design and multi-band antenna design. It also includes a new theoretical analysis of noise coupling in low noise phased array receivers.In LNA design much depends on the choice of the optimum active devices. A comprehensive survey of the performance of low noise transistors is therefore extremely beneficial. To this end a comparison of the DC, small-signal and noise behaviours of 10 state-of-the-art GaAs and InP based pHEMT and mHEMT low noise processes has been carried out. Their suitability in LNA designs has been determined, with emphasis on the SKA project. This work is part of the first known detailed investigation of this kind. Results indicate the superiority of mature GaAs-based pHEMT processes, and highlight problems associated with the studied mHEMT processes. Two of the more promising processes have then been used to design C-band and UHF-band MMIC LNAs. A new theoretical analysis of coupled noise between antenna elements of a low noise phased array receiver has been carried out. Results of the noise wave analysis, based on fundamental principles of noisy networks, suggest that the coupled noise contribution to system noise temperatures should be smaller than had previously been suggested for systems like the SKA. The principles are applicable to any phased array receiver. Finally, a multi-band antenna has been designed and fabricated for a severe operating environment, covering the three extremely crowded frequency bands, the 2.1 GHz UMTS, the 2.4 GHz ISM and the 5.8 GHz ISM bands. Measurements have demonstrated excellent performance, exceeding that of equivalent commercial antennas aimed at similar applications.
136

Implementation of routines for the estimation of winds and precipitation of a wind profiler radar with spaced antenna design that operates in UHF band / info:eu-repo/semantics/bachelorThesis

Bocanegra Salas, Erick Brayam 09 December 2019 (has links)
El Instituto Geofísico del Perú ha desarrollado un proyecto, financiado por INNOVATE Perú, llamado “Diseño e implementación de un radar perfilador de vientos que opera en UHF para estudios de turbulencias y precipitación en el territorio peruano”, este proyecto es la propuesta de solución a una limitación presentada por la comunidad científica del Perú y otras entidades para hacer estudios climáticos de vientos y precipitación. Parte del desarrollo de este radar, es el procesamiento de los datos recibidos. En esta tesis se ha hecho un análisis del diseño, frecuencia y tipo de radar que fue diseñado para luego seleccionar los algoritmos de procesamiento necesarios. Los algoritmos que se desarrollaron para el procesamiento del radar UHF permiten estimar vientos troposféricos y turbulencia con la técnica de análisis espectral total. Además de medir la intensidad de precipitación y el factor de reflectividad obtenido de las lluvias con la relación del diámetro de gotas y el factor de reflectividad. Los resultados de estas estimaciones, posteriormente son comparados con otros instrumentos para su validación y su posterior aplicación. / The Geophysical Institute of Peru (IGP) has developed a project called "Design and implementation of a radar profiler that operates in UHF for studies of turbulence and precipitation in the Peruvian territory", this project is the proposed solution to a limitation presented by the scientific community of Peru and other entities to conduct climate studies of winds and precipitation. Part of the development of this radar is the processing of received data. In this thesis an analysis of the design, frequency and type of the designed radar was done to then select the appropriate processing algorithms. The algorithms that were developed for the UHF radar processing allows the estimation of tropospheric winds and turbulence with the full spectral analysis technique. In addition to measuring the intensity of precipitation and the reflectivity factor obtained from rainfall related to the diameter of drops and the reflectivity factor. The results of these estimates are then compared with other instruments for validation and subsequent application. / Tesis

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