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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.
181

New directions in advanced RFID systems.

Ranasinghe, Damith Chinthana January 2007 (has links)
Title page, abstract and table of contents only. The complete thesis in print form is available from the University of Adelaide Library. / A combination of Radio Frequency Identification technology and ubiquitous computing are revolutionising the manner in which we look at simple objects. Radio Frequency Identification (RFID) allows RFID labeled objects to be identified at a distance without physical contact, and ubiquitous computing provides a virtually connected environment for the objects. RFID labels are frequently referred to as the next generation barcodes. RFID Systems provide increased productivity, efficiency, convenience and many advantages over bar codes for numerous applications, especially global supply chain management. RFID labeling has a number of advantages over conventional bar code systems. The optics based bar code systems could be rendered useless by common everyday environments containing dirt, dust, smoke, grease, condensation and by misorientation and misalignment. Furthermore bar codes are subject to fraudulent duplication and counterfeiting with minimal effort. However, there are limitations and constraints inherent to RFID technology: semiconductor thresholds, limits on transmitted power, costs, antenna and coupling inefficiencies. Thus it is important for RFID designers to understand these limitations and constraints in order to optimise system designs and overcome inefficiencies where possible. Therefore the work presented in this dissertation seeks to improve the performance of advanced RFID systems by overcoming a number of these limitations. Prior to a discussion of improving performance, the author's interpretation of a modem RFID system along its evolutionary path as a ubiquitous RFID network and its application to supply chain management is described. Performance improvements are achieved by: the development of electromagnetic theory for RFID system analysis and optimisation; design and development of interrogator antennas; analysis of electrically small and tiny antennas for RFID labels; and development and utilisation of a design methodology for creating high performance label antennas and antennas for tagging metallic objects. Implementations of RFID systems have raised concerns regarding information security and possible violations of end-user privacy. The most profound concerns are raised against low cost RFID technology because of its potential for mass scale deployment, its pervasive nature, and the resource limitations preventing the provision of strong cryptographic solutions. There is a growing need in the RFID community to discover and develop techniques and methods to overcome various hurdles posed by the above-mentioned concerns. Thus, the thesis also considers the vulnerabilities of low cost RFID systems and associated insecurities and privacy concerns resulting from the latter. Prior to addressing such concerns impeding the deployment of low cost RFID technology, a framework within which to provide security services is also detailed. It has become important to both defme and identity a framework based around low cost RFID systems since RFID has become a "catch all" phrase for various other forms of technology. Addressing security and privacy of low cost RFID systems requires novel thinking. The later parts of the thesis outline design considerations for security mechanisms and a number of practicable solutions for providing the features of: mutual authentication; confidentiality; message content security; product authentication; anonymity and untraceability, that are necessary for low cost RFID systems to overcome the weaknesses identified in this dissertation. Implementing these security mechanisms requires the generation of true random tag parameters and true random numbers. Achieving these objectives using a hardware based true random number generator is also described and analysed. A final part of the thesis focuses on active RFID labels and improving their performance. The primary concern with active labels is the life of the onboard battery. Turn-on circuits provide a method of turning "on" and "off" an active label remotely to conserve valuable battery power. Analysis, development and testing of a turn-on circuit concept, based on interrogator field sensing, have provided a means of remotely activating and deactivating active RFID labels and conserving battery power. The final chapter of this thesis provides a detailed analysis, based on coupling relations between electromechanical systems, for evaluating the feasibility of a theft detection sensor, based on a turn-on circuit for an active RFID label, for preventing the theft of high value items. While low cost RFID needs to overcome certain security and privacy related barriers, RFID technology does provide novel and valid approaches to such security related applications as product authentication, anti-counterfeiting and theft detection. It is believed that the contributions from this thesis will extend and elaborate on the existing knowledge base, paving the way forward to allow further significant deployment of advanced RFID techno logy. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1368084 / Thesis (Ph.D.) -- University of Adelaide, School of Electrical and Electronic Engineering, 2007
182

Inductors in high-performance silicon radio frequency integrated circuits : analysis, modeling, and design considerations

Lutz, Richard D. Jr 22 July 2005 (has links)
Spiral inductors are a key component of mixed-signal and analog integrated circuits (IC's). Such circuits are often fabricated using silicon-based technology, owing to the inherent low-cost and high volume production aspects. However, semiconducting substrate materials such as silicon can have adverse effects on spiral inductor performance due to the lossy nature of the material. Since the operating requirements of many high performance IC's demand reactive components that have high Quality Factor's (Q's), and are thus low loss devices, the need for accurate modeling of such structures over lossy substrate media is key to successful circuit design. The Q's of commonly available off-chip inductors are in the range of 50- 100 for frequencies ranging up to a few gigahertz. Since off-chip inductors must be connected through package pins, solder bumps, etc., which all contribute additional loss and thus lower the apparent Q of an external device, the typical on-chip Q requirement for a given RFIC design is generally lower than that for an off-chip spiral solution. However, a spiral inductor that was designed and fabricated originally in a low loss technology such as thin-film alumina may have substantially worse performance in regard to Q if it is used in a silicon-based technology, owing to the conductive substrate. For this reason, it is imperative that semiconducting substrate effects be accurately accounted for by any modeling effort for monolithic spirals in RFICs. This thesis presents a complete modeling solution for both single and multi-level spiral inductors over lossy silicon substrates, along with design considerations and methods for mitigation of the undesirable performance effects of semiconducting substrates. The modeling solution is based on Spectral Domain Approach (SDA) solutions for frequency dependent complex capacitive (i.e. both capacitance and conductance) parasitic elements combined with a quasi-magnetostatic field solution for calculation of the frequency dependent complex inductive (i.e. both inductance and resistance) terms. The effects of geometry and process variations are considered as well as the incorporation of Patterned Ground Shields (PGS) for the purpose of Q enhancement. Proposals for future extensions of this work are discussed in the concluding chapter. / Graduation date: 2006
183

Steady-state analysis techniques for coupled device and circuit simulation

Hu, Yutao 28 May 2004 (has links)
The focus of this work is on the steady-state analysis of RE circuits using a coupled device and circuit simulator. Efficient coupling algorithms for both the time-domain shooting method and the frequency-domain harmonic balance method have been developed. A modified Newton shooting method considerably improves the efficiency and reliability of the time-domain analysis. Three different implementation approaches of the harmonic balance method for coupled device and circuit simulation are investigated and implemented. These include the quasi-static, non-quasi-static, and modified-Volterra-series approaches. Comparisons of simulation and performance results identify the strengths and weakness of these approaches in terms of accuracy and efficiency. / Graduation date: 2005
184

Design and development of novel radio frequency identification (RFID) tag structures

Yang, Li 13 November 2009 (has links)
The objective of the proposed research is to design and develop a series of radio frequency identification (RFID) tag structures that exhibit good performance characteristics with cost optimization and can be realized on flexible substrates such as liquid crystal polymer (LCP), paper-based substrate and magnetic composite material for conformal applications. The demand for flexible RFID tags has recently increased tremendously due to the requirements of automatic identification in various areas. Several major challenges existing in today's RFID technologies need to be addressed before RFID can eventually march into everyone's daily life, such as how to design high performance tag antennas with effective impedance matching for passive RFID IC chips to optimize the power performance, how to fabricate ultra-low-cost RFID tags in order to facilitate mass production, how to integrate sensors with passive RFID tags for pervasive sensing applications, and how to realize battery-free active RFID tags in which changing battery is not longer needed. In this research, different RFID tag designs are realized on flexible substrates. The design techniques presented set the framework for answering these technical challenges for which, the focus will be on RFID tag structure design, characterization and optimization from the perspectives of both costs involved and technical constraints.
185

New directions in advanced RFID systems.

Ranasinghe, Damith Chinthana January 2007 (has links)
Title page, abstract and table of contents only. The complete thesis in print form is available from the University of Adelaide Library. / A combination of Radio Frequency Identification technology and ubiquitous computing are revolutionising the manner in which we look at simple objects. Radio Frequency Identification (RFID) allows RFID labeled objects to be identified at a distance without physical contact, and ubiquitous computing provides a virtually connected environment for the objects. RFID labels are frequently referred to as the next generation barcodes. RFID Systems provide increased productivity, efficiency, convenience and many advantages over bar codes for numerous applications, especially global supply chain management. RFID labeling has a number of advantages over conventional bar code systems. The optics based bar code systems could be rendered useless by common everyday environments containing dirt, dust, smoke, grease, condensation and by misorientation and misalignment. Furthermore bar codes are subject to fraudulent duplication and counterfeiting with minimal effort. However, there are limitations and constraints inherent to RFID technology: semiconductor thresholds, limits on transmitted power, costs, antenna and coupling inefficiencies. Thus it is important for RFID designers to understand these limitations and constraints in order to optimise system designs and overcome inefficiencies where possible. Therefore the work presented in this dissertation seeks to improve the performance of advanced RFID systems by overcoming a number of these limitations. Prior to a discussion of improving performance, the author's interpretation of a modem RFID system along its evolutionary path as a ubiquitous RFID network and its application to supply chain management is described. Performance improvements are achieved by: the development of electromagnetic theory for RFID system analysis and optimisation; design and development of interrogator antennas; analysis of electrically small and tiny antennas for RFID labels; and development and utilisation of a design methodology for creating high performance label antennas and antennas for tagging metallic objects. Implementations of RFID systems have raised concerns regarding information security and possible violations of end-user privacy. The most profound concerns are raised against low cost RFID technology because of its potential for mass scale deployment, its pervasive nature, and the resource limitations preventing the provision of strong cryptographic solutions. There is a growing need in the RFID community to discover and develop techniques and methods to overcome various hurdles posed by the above-mentioned concerns. Thus, the thesis also considers the vulnerabilities of low cost RFID systems and associated insecurities and privacy concerns resulting from the latter. Prior to addressing such concerns impeding the deployment of low cost RFID technology, a framework within which to provide security services is also detailed. It has become important to both defme and identity a framework based around low cost RFID systems since RFID has become a "catch all" phrase for various other forms of technology. Addressing security and privacy of low cost RFID systems requires novel thinking. The later parts of the thesis outline design considerations for security mechanisms and a number of practicable solutions for providing the features of: mutual authentication; confidentiality; message content security; product authentication; anonymity and untraceability, that are necessary for low cost RFID systems to overcome the weaknesses identified in this dissertation. Implementing these security mechanisms requires the generation of true random tag parameters and true random numbers. Achieving these objectives using a hardware based true random number generator is also described and analysed. A final part of the thesis focuses on active RFID labels and improving their performance. The primary concern with active labels is the life of the onboard battery. Turn-on circuits provide a method of turning "on" and "off" an active label remotely to conserve valuable battery power. Analysis, development and testing of a turn-on circuit concept, based on interrogator field sensing, have provided a means of remotely activating and deactivating active RFID labels and conserving battery power. The final chapter of this thesis provides a detailed analysis, based on coupling relations between electromechanical systems, for evaluating the feasibility of a theft detection sensor, based on a turn-on circuit for an active RFID label, for preventing the theft of high value items. While low cost RFID needs to overcome certain security and privacy related barriers, RFID technology does provide novel and valid approaches to such security related applications as product authentication, anti-counterfeiting and theft detection. It is believed that the contributions from this thesis will extend and elaborate on the existing knowledge base, paving the way forward to allow further significant deployment of advanced RFID techno logy. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1368084 / Thesis (Ph.D.) -- University of Adelaide, School of Electrical and Electronic Engineering, 2007
186

CMOS RF front-end design of a very narrowband transceiver with 0.18[micrometers]

Chen, Chih-Hung, January 2008 (has links)
Thesis (M.S.)--University of Texas at El Paso, 2008. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.
187

Adaptive digital polynomial predistortion linearisation for RF power amplifiers : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Engineering in Electrical and Computer Engineering at the University of Canterbury, Christchurch, New Zealand /

Giesbers, D. M. January 1900 (has links)
Thesis (M.E.)--University of Canterbury, 2008. / Typescript (photocopy). "August 2008." Includes bibliographical references (p. [123]-126). Also available via the World Wide Web.
188

The role of independent advocacy groups in RFID technology use the current status of RFID technology adoption in New Zealand : a thesis submitted to Auckland University of Technology in partial fulfilment of the requirements for the degree of Master of Computer and Information Sciences (MCIS), 2008 /

Zhang, Jiayu. January 2007 (has links)
Thesis (MCIS - Computer and Information Sciences)--AUT University, 2007. / Includes bibliographical references. Also held in print (vii, 94 leaves ; 30 cm.) in the Archive at the City Campus (T 658.514 ZHA).
189

Voltage controlled oscillators and high Q copper inductors.

Rogers, John W. M. January 1900 (has links)
Thesis (M. Eng.)--Carleton University, 1999. / Includes bibliographical references. Also available in electronic format on the Internet.
190

Aspects of dedicated (dormant) chip for intelligent part handling by industrial robots

Theron, Stephanus Andreas 12 September 2012 (has links)
M.Ing. / Intelligent object identification (the ability to find the identity, position and orientation of an remote object) in a Manufacturing environment plays an important role in the areas of Automation and Manufacturing. Radio frequency identification (RFID) systems have solve the problem of finding the identity of a remote object, but it fails to determine the position and orientation. The Global Positioning System (GPS) have a solution to find the position of a remote object in the global environment, but in a Manufacturing environment it fails. The main obstacle to overcome in finding a unique solution with radio frequency technology is reflections. This thesis investigates the idea of finding the identity, position (and orientation) of a (dormant) chip remotely. The chip transmits a binary signal at 244kHz. The string is Amplitude modulated. The receiver demodulates the signal to obtain the chip's identity. The receiver antenna is divided into four quadrants. First the quadrant in which the chip is located are determined. Three different voltages are then measured to obtain the position of the chip in the specific quadrant. Reflections can be ignored since the system works at a low frequency.

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