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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.
381

Design och implementering av enhandsburen RFID-läsare / Design and implementation of a handheld RFID-reader

Nordström, Edward, Hollander, Johan January 2008 (has links)
Radio frequency identification (RFID) is a versatile wireless technology usedworldwide. The fields of applications are many and its popularity constantlygrows due to smaller in size, better and less expensive components. RFID isused to identify, track or share information about an object using radio waves. This master thesis describes the process of designing and implementing ahandheld UHF RFID reader. The goal was to, based on a UHF RFID-chipdesign a fully functional, small in size and power efficient device. Amicrocontroller provides the user interface and is also used to control theRFID-chip and a Bluetooth device. A Bluetooth- and GPRS-compatible mobilephone will be used to forward data to a server connected to the Internet. Allparts of the design are described, such as the printed circuit board design aswell as the software for the micro controller and the mobile phone. Because the extent of this thesis it is neither possible nor necessary to dig toodeep into the Bluetooth- or GPRS-protocol. The focus will be on designingsoftware and hardware for the handheld unit. / Radio frekvens identifiering (RFID) är en mångsidig trådlös teknik somanvänds över hela världen. Områdena där tekniken används är många och dess popularitet växer konstant tack vare mindre storlek, bättre och billigarekomponenter. RFID används för att identifiera, spåra eller dela med siginformation om ett objekt med radiovågor. Det här examensarbetet beskriver processen av design och implementering aven handburen UHF RFID läsare. Målet har varit att, baserat på ett UHF-RFIDchip, designa en fullt fungerande, liten och strömsnål enhet. En microcontroller förser dels användaren med ett användargränssnitt och sköter delskommunikationen med RFID chip och en blåtandsmodul. En blåtands- ochGPRS- eller 3G-kompatibel mobiltelefon används for att skicka vidare data tillen server kopplad till Internet. Alla delar av designen är beskrivna, så som PCB design, mjukvara för micro controllern och mobiltelefonen. På grund av omfattningen av det här examensarbetet så har det inte varitmöjligt eller nödvändigt att gräva för djupt i Blåtands- eller GPRS/3Gprotokollen. Fokus är på att designa hårdvara och mjukvara för den handhållna enheten.
382

Methodologies for low-cost testing and self-healing of rf systems

Goyal, Abhilash 21 April 2011 (has links)
This thesis proposes a multifaceted production test and post-manufacture yield enhancement framework for RF systems. This framework uses low-cost test and post-manufacture calibration/tuning techniques. Since the test cost and the yield of the RF circuits/sub-system directly contribute to the manufacturing cost of RF systems, the proposed framework minimizes overall RF systems' manufacturing cost by taking two approaches. In the first approach, low-cost testing methodologies are proposed for RF amplifiers and integrated RF substrates with an embedded RF passive filter and interconnect. Techniques are developed to test RF circuits by the analysis of low-frequency signal of the order of few MHz and without using any external RF test-stimulus. Oscillation principles are used to enable testing of RF circuits without any external test-stimulus. In the second approach, to increase the yield of the RF circuits for parametric defects, RF circuits are tuned to compensate for a performance loss during production test using on-board or on-chip resources. This approach includes a diagnosis algorithm to identify faulty circuits within the system, and performs a compensation process that adjusts tunable components to enhance the performance of the RF circuits. In the proposed yield improvement methodologies, the external test stimulus is not required because the stimulus is generated by the RF circuit itself with the help of additional circuitry and faulty circuits are detected using low-cost test methods developed in this research. As a result, the proposed research enables low-cost testing and self-healing of RF systems.
383

Design och implementering av enhandsburen RFID-läsare / Design and implementation of a handheld RFID-reader

Nordström, Edward, Hollander, Johan January 2008 (has links)
<p>Radio frequency identification (RFID) is a versatile wireless technology usedworldwide. The fields of applications are many and its popularity constantlygrows due to smaller in size, better and less expensive components. RFID isused to identify, track or share information about an object using radio waves.</p><p>This master thesis describes the process of designing and implementing ahandheld UHF RFID reader. The goal was to, based on a UHF RFID-chipdesign a fully functional, small in size and power efficient device. Amicrocontroller provides the user interface and is also used to control theRFID-chip and a Bluetooth device. A Bluetooth- and GPRS-compatible mobilephone will be used to forward data to a server connected to the Internet. Allparts of the design are described, such as the printed circuit board design aswell as the software for the micro controller and the mobile phone.</p><p>Because the extent of this thesis it is neither possible nor necessary to dig toodeep into the Bluetooth- or GPRS-protocol. The focus will be on designingsoftware and hardware for the handheld unit.</p> / <p>Radio frekvens identifiering (RFID) är en mångsidig trådlös teknik somanvänds över hela världen. Områdena där tekniken används är många och dess popularitet växer konstant tack vare mindre storlek, bättre och billigarekomponenter. RFID används för att identifiera, spåra eller dela med siginformation om ett objekt med radiovågor.</p><p>Det här examensarbetet beskriver processen av design och implementering aven handburen UHF RFID läsare. Målet har varit att, baserat på ett UHF-RFIDchip, designa en fullt fungerande, liten och strömsnål enhet. En microcontroller förser dels användaren med ett användargränssnitt och sköter delskommunikationen med RFID chip och en blåtandsmodul. En blåtands- ochGPRS- eller 3G-kompatibel mobiltelefon används for att skicka vidare data tillen server kopplad till Internet. Alla delar av designen är beskrivna, så som PCB design, mjukvara för micro controllern och mobiltelefonen.</p><p>På grund av omfattningen av det här examensarbetet så har det inte varitmöjligt eller nödvändigt att gräva för djupt i Blåtands- eller GPRS/3Gprotokollen. Fokus är på att designa hårdvara och mjukvara för den handhållna enheten.</p>
384

Experimental Studies Of Electron Spin Dynamics In Semiconductors Using A Novel Radio Frequency Detection Technique

Guite, Chinkhanlun 06 1900 (has links) (PDF)
A novel experimental setup has been realized to measure weak magnetic moments which can be modulated at radio frequencies (~1–5 MHz). Using an optimized radio-frequency (RF) pickup coil and lock-in amplifier, an experimental sensitivity of 10 -15 Am2 corresponding to 10 -18 emu has been demonstrated with a one second time constant. The detection limit at room temperature is 9.3 10 -16 Am2/√Hz limited by Johnson noise of the coil. In order to demonstrate the sensitivity of this technique it was used to electrically detect the polarized spins in semiconductors in zero applied magnetic fields. For example in GaAs, the magnetic moment due to a small number (~ 7 x 108) of spin polarized electrons generated by polarization modulated optical radiation was detected. Spin polarization was generated by optical injection using circularly polarized light which is modulated rapidly using an electro-optic cell. The modulated spin polarization generates a weak time-varying magnetic field which is detected by the sensitive radio-frequency coil. Using a radio-frequency lock-in amplifier, clear signals were obtained for bulk GaAs and Ge samples from which an optical spin orientation efficiency of ~ 10–20% could be determined for Ge at 1342 nm excitation wavelength at 127 K. In the presence of a small external magnetic field, the signal decayed according to the Hanle Effect, from which a spin lifetime of 4.6 ± 1.0 ns for electrons in bulk Ge at 127 K was extracted. The spin dynamics in n-Ge was further explored and the temperature dependence of the spin lifetime was plotted for a temperature range of about 90 K to 180 K. The temperature dependence of the optical pumping efficiency was also measured though no quantitative conclusions could be derived. The signals observed for semi-insulating GaAs, n-GaAs, GaSb and CdTe which are direct gap semiconductors are much larger than expected (almost two orders of magnitude). An attempt was made to explain this unexpected behavior of these direct gap semiconductors using the spin hall effect.
385

RFID-teknologi på distributionscentral Som digital inleveransmetod : framgångsfaktorer vid implementering / RFID-Technologies in a warehouse Used as a digital method for receiving incoming goods : Success factors for implementation

Geidne, Tim January 2019 (has links)
En IT-styrd lager och orderhantering är idag vanligt, metoden för att ta emot leveranser har dock sett likadan ut länge. Man använder sig oftast av streckkoder/QR-koder eller rent manuell hantering med penna och papper. Radio frequency identification (RFID) möjliggör en trådlös och autonom avläsning av gods som är taggade. Tekniken har funnits länge men har under senaste år visats sig få en mer positiv trend, där mer och mer objekt blir taggade. Samarbetspartnern i denna studie Fiskarhedenvillan använder sig idag av ett helt manuellt system för inleveranser av gods på deras distributionscentral. De vill nu börja deras digitalisering av distributionscentralen genom att undersöka möjligheten att införa ett RFID-system som metod för hantering av gods vid inleveranser. Denna studie har i samarbete med Sogeti och Fiskarhedenvillan genomförts för att identifiera möjligheter och faktorer och undersöka ifall en implementation är möjlig. Intervjuer har genomförts med nyckelpersoner inom vad som kallats ”världens bästa RFID-projekt”. Från slutsatserna identifieras ett antal utmaningar kring processer av flöden som måste uppdateras för att kunna dra full nytta utav ett RFID-system. Vidare så blir RFID teknik som metod för inleverans av gods sällan mer effektivt, man måste också börja kolla på arbetssätt och börja utveckla de nuvarande processerna för att kunna utnyttja fördelarna med RFID. Då möjligheten att gardera sig mot en icke fulländad logistik-kedja med kombinerad tagg/streckkods-etikett samtidigt som mer och mer blir taggat gör det att RFID-system blir mer direkt användbara. Implementeringar underlättas av befintliga beprövade standarder. Kritiska faktorer att beakta inför implementering innebär bland annat omgivningsanalys och att implementeringar utav RFID-system ofta har stor inverkan på hela kedjan. Vidare identifieras möjligheter som tidigare beprövade system och en positiv trend för implementeringar inom RFID-tekniken. / An IT-controlled warehouse and order management is today common, however, the method for receiving deliveries has looked the same for a long time. You usually use bar codes / QR codes or purely manual handling with pen and paper. Radio frequency identification (RFID) enables a wireless and autonomous reading of goods that have been tagged. The technology has been aorund for a long time but has been shown to have a more positive trend in recent years, where more and more objects are being tagged. The partner in this study Fiskarhedenvillan today uses a completely manual system for deliveries of goods at their distibution center. They now want to start their digitalization of the distribution center by examining the posibility of introducing an RFID-system as a method for hondling goods at deliveries. This study, in collaboration with Sogeti and Fiskarhedenvillan, has been carried out to identify opportunities and factors and to investigate wether an implemantation is possible. Interviews have been conducted with key personell within what has been called ”the world’s best RFID project”. From the conclusions, a number of challenges are identified around processes of flows that must be updated to be able to take full advantage of an RFID system. Futhermore, RFID technology as a method for receiving goods rarely becomes more efficient unless the processes between flows are changed or updated, and the working methods should also be looked upon to be able to utilize the advantages of RFID. Since the possibility of gourding against an uncompleted logistics chain with a combined tag / barcode label at the same time as more and more objects are being tagged, it makes RFID systems more directly usable. Implementations are facilitated by existing proven standards. Critical factors to consider prior to implementation include environmental analysis and that implementations of RFID systems often have a great impact on the entire chain. Furthermore, opportunities are identified as previously proven systems and a positive trend for implementations in the RFID field.
386

Etude de la compatibilité radioélectrique du futur système de communication aéronautique en bande L. / Radiofrequency compatibility of the future aeronautical communication system in the L band

Neji, Najett 12 December 2011 (has links)
Au début des années 2000, les instances aéronautiques ont exprimé le besoin de développer un nouveau système de radiocommunication aéronautique du fait de l'augmentation du trafic aérien et de la saturation croissante des capacités de communication radio entre les aéronefs et les stations de contrôle aérien. L'une des composantes de ce système, nommée L-DACS (« L-band Digital Aeronautical Communication System »), devrait opérer dans la bande L-aéronautique (960-1164 MHz), dans laquelle fonctionnent également de nombreux autres systèmes radioélectriques. La compatibilité radioélectrique (CRE) de L-DACS avec ces systèmes est un des facteurs principaux à prendre en considération dans le développement d'un tel système.L'objectif principal de cette thèse est d'identifier les principaux problèmes reliés à la CRE et d'en étudier les cas critiques. Ces travaux sont fondamentaux en aéronautique, puisque tout dysfonctionnement dans la communication ou dans les systèmes de radionavigation peut mettre en danger la sécurité du vol. Les conclusions de cette thèse contribueront à la normalisation du système L-DACS et à la finalisation de ses spécifications.Dans une première étape, on étudie l'état de l'art dans les communications aéronautiques et en CRE. On analyse en particulier les dernières spécifications des deux systèmes candidats L-DACS. Ensuite, on propose un algorithme de calcul de brouillage dans le but d'étudier la CRE dans le domaine fréquentiel, d'en identifier et d'en traiter les cas critiques. L'analyse fréquentielle étant insuffisante dans plusieurs cas, on propose alors une approche temporelle d'étude de CRE. Après en avoir présenté les avantages, on présente un exemple d'étude de l'effet d'un système L-DACS sur un récepteur DME (« Distance Measuring Equipment ») à l'aide d'un banc de test CRE aéronautique.Cette thèse a été réalisée en collaboration avec la Direction Générale de l'Aviation Civile (DGAC), qui est un acteur principal pour la réglementation des communications et un affectataire de fréquence pour le spectre aéronautique en France. La thèse contribue aux études menées par la DGAC à l'échelle nationale et internationale.Dans les perspectives, on propose la poursuite de cette étude par une approche temporelle plus générale pour étudier la CRE entre des systèmes radioélectriques quelconques en tenant compte de paramètres supplémentaires liés à la dynamique des systèmes et aux propriétés de leurs technologies. / In the beginning of the 21th century, the aeronautical authorities expressed their need to develop a new system for aeronautical radiocommunications, because the air-traffic is increasing and that current communication systems between pilots and air-controllers are reaching their capacity limits. The L-band Digital Aeronautical Communication System (L-DACS) is the part of the future system that will be operating in a part of the aeronautical L-band (960-1164 MHz), already occupied by a large number of radio-frequency legacy systems. Consequently, it is essential to consider its radio-frequency compatibility (RFC) for the development of the future L-DACS system. This thesis aims at identifying the principal issues related to RFC and studying its critical situations. Such topics are fundamental in aeronautics, as any communication or radionavigation dysfunction may endanger flight and passengers security. Some obtained results will be used for the L-DACS standardization and its specifications finalization. We first analyze the state-of-the-art in both aeronautical communications and RFC, focalizing on updated specifications of both preselected L-DACS candidate systems. We then propose a deterministic algorithm to compute the interference level in order to study the RFC in the frequency domain under identified critical scenarios. Since the frequency-domain analysis seems to be insufficient in several cases, we develop a different methodology, called the time-frequency approach, to analyze the RFC for such situations. We apply this new approach to analyze the effect of an L-DACS interferer on a Distance Measuring Equipment (DME) receiver, using an aeronautical RFC test-bed that we implemented at SUPELEC. This work has been performed in collaboration with the French Civil Aviation Authorities (DGAC), which are an important actor in aeronautical communication regulations and aeronautical spectrum management in France. The thesis contributes to DGAC studies at national as well as international levels. For further work, we suggest to generalize the proposed time-frequency approach to analyze the RFC between any two radio-frequency systems, taking into account additional parameters related to system dynamics and their technology properties.
387

A 40 GHz Power Amplifier Using a Low Cost High Volume 0.15 um Optical Lithography pHEMT Process

Mays, Kenneth W. 04 January 2013 (has links)
The demand for higher frequency applications is largely driven by bandwidth. The evolution of circuits in the microwave and millimeter frequency ranges always demands higher performance and lower cost as the technology and specification requirements evolve. Thus the development of new processes addressing higher frequencies and bandwidth requirements is essential to the growth of any semiconductor company participating in these markets. There exist processes which can perform in the higher frequency design space from a technical perspective. However, a cost effective solution must complement the technical merits for deployment. Thus a new 0.15 um optical lithography pHEMT process was developed at TriQuint Semiconductor to address this market segment. A 40 GHz power amplifier has been designed to quantify and showcase the capabilities of this new process by leveraging the existing processing knowledge and the implementation of high frequency scalable models. The three stage power amplifier was designed using the TOM4 scalable depletion mode FET model. The TriQuint TQP15 Design Kit also implements microstrip transmission line models that can be used for evaluating the interconnect lines and matching networks. The process also features substrate vias and the thin film resistor and MIM capacitor models which utilize the capabilities of the BCB process flow. During the design stage we extensively used Agilent ADS program for circuit and EM simulation in order to optimize the final design. Special attention was paid to proper sizing of devices, developing matching circuits, optimizing transmission lines and power combining. The final design exhibits good performance in the 40 GHz range using the new TQP15 process. The measured results show a gain of greater than 13 dB under 3 volt drain voltage and a linear output power of greater than 28 dBm at 40 GHz. The 40 GHz power amplifier demonstrates that the new process has successfully leveraged an existing manufacturing infrastructure and has achieved repeatability, high volume manufacturing, and low cost in the millimeter frequency range.
388

Design of high performance RFID systems for metallic item identification.

Ng, Mun Leng January 2008 (has links)
Although the origins of Radio Frequency Identification (RFID) technology can be traced back for many years, it is only recently that RFID has experienced rapid growth. That growth is mainly due to the increasing application of this technology in various supply chains. The widening of the implementation of RFID technology in supply chains has posed many challenges and one of the biggest is the degradation of the RFID system performance when tagging metallic objects, or when the RFID system operates in a metallic environment. This thesis focuses on tackling the issue of having metallic objects in an Ultra High Frequency (UHF) RFID system. The work presented in this thesis contributes to the research on UHF RFID systems involving metallic objects in several ways: (a) the development of novel RFID tags that range from a simple tag for general applications to tags suitable for metallic object identification; (b) the tag designs target the criteria of minimal tag size and cost to embrace the vision of item level tagging; and (c) the analysis of the performance (through theoretical predictions and practical measurements) of an RFID tag near metallic structures of various shapes and sizes. The early part of this thesis provides a brief introduction to RFID and reviews the background information related to metallic object identification for UHF RFID systems. The process of designing a basic tag, and additional information and work done related to the process, are outlined in the early part of this thesis. As part of this fundamental research process, and before proceeding to the designing of tags specifically for metallic objects, a small and low cost RFID tag for general applications was developed. Details of the design of this tag, with the application of this tag for animal identification, are presented. In the later parts of the work, different tag design approaches were explored and this has generated three rather different RFID tags suitable for attaching to metallic objects. The aim of this research is not just to design tags for metallic objects but also to tackle the constraints of having tags that are small in size, cost effective and suited in size to some familiar objects. Hence, in the later part of this research, the work took a step further where one of the three tags designed for metallic objects addressed the challenge of identifying individual small metallic beverage cans. RFID involves tagging of different types of objects and a tag may be required to be located in a depression of a metallic object. In the final part of this research, the read range performance of one of the RFID tags designed for metallic objects was analysed when the tag was located in metallic depressions of various shapes and sizes. The analysis was performed from a combination of theoretical calculation and simulation perspectives, and also through practical real-life measurements. Metallic objects are very common around us. Their presence is unavoidable and so to identify them, having the appropriate RFID tags suitable for operation on metallic surfaces is essential. Frequently the tags must be small in size and low in cost to allow identification at item level of individual small metallic objects. Understanding and being aware of the potential effects of metallic structures of various shapes and sizes on the tag performance is thus important. The research in this thesis into all the above can bring the industry further towards full deployment of RFID down to item level tagging. / Thesis (Ph.D.) - University of Adelaide, School of Electrical and Electronic Engineering, 2008
389

Implementation and Applications of an Anti-Collision Differential-Offset Spread Spectrum RFID System

Rohatgi, Anil 11 August 2006 (has links)
This report documents the design, construction, and implementation of a differential-offset spread spectrum RFID system, to avoid the problem of anti-collision interference from multiple RFID tags. Currently in industry, this problem is handled by establishing a two way communication link between the tags and the interrogator. The proposed system eliminates the need for the excessive hardware use to create this link, and therefore drastically reduces the cost of each tag. Not only is this system cheaper to implement but it is faster, requires less power, and by the nature of the design contains an inherent encryption scheme for the data being transmitted. Specialized RFID tags were designed and fabricated in order to produce a pseudo random code unique to each tag. The design presented in this document allowed simultaneous interrogation of up to 255 tags within one sensing environment. Once queried, the tags then modulate the incoming signal from the interrogator with their own sequence, and reflect the signal back to the interrogator. What the interrogator then receives is a combination of backscatter from all of the tags within the sensing environment. Specialized software written in Matlab and LabView uses these unique sequences to isolate the data from a desired tag away from the sea of information being transmitted from every tag. Using this system, numerous applications for experiments and measurements can be devised. One such application this thesis focuses on is the use of this system to simultaneously measure signal strengths from multiple diversity antennas in order to optimize their position and orientation. Currently, the majority of antenna diversity measurements are taken by measuring the signal strength of a given configuration one antenna at a time. By using the anti-collision RFID system proposed above, the signal strength produced by both antennas can be measured and recorded simultaneously to provide a true representation of their combined performance. This measurement can be used to find the optimal configuration for multiple antennas. This thesis will fully explore the theories and procedures behind creating this system, and will provide the results and analysis of its performance.
390

Integration of passive RFID location tracking for real-time visualization in building information models (BIM)

Costin, Aaron M. 13 January 2014 (has links)
Navigation through large and unfamiliar facilities with labyrinths of corridors and rooms is difficult and often results in a person being lost. Additionally, locating a specific utility within a facility is often a tough task. The hypothesis tested in this research is that integrating real-time automated sensing technology and a Building Information Model will provide real time visualization that can assist in localization and navigation of a facility. The scope of this research is facility maintenance management during the Operation and Maintenance (O&M) phase of a facility. The thesis demonstrates how the integration of passive Radio Frequency Identification (RFID) tracking technology and Building Information Modeling (BIM) can assist in facilities maintenance management. The objectives of this research included 1) developing a framework that utilizes the integration of commercially-available RFID and a BIM model; 2) evaluating the framework for real-time resource location tracking within an indoor environment; and 3) developing an algorithm for real-time localization and visualization in a BIM model. A prototype application has been developed that simultaneously connects the RFID readers, a database, and a BIM model. The goal of this system is to have a real-time localization accuracy of 3 meters at 95% confidence. Testing was conducted in laboratory conditions, and the results show that the system error was within the 3 meters goal.

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