Nie, Jing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 73-77). / Abstracts in English and Chinese. / Abstract --- p.i / Abstract (Chinese Version) --- p.iii / Acknowledgement --- p.iv / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Technology Overview --- p.4 / Chapter 2.1 --- History --- p.5 / Chapter 2.2 --- RFID Systems --- p.7 / Chapter 2.2.1 --- Tag --- p.8 / Chapter 2.2.2 --- Reader --- p.10 / Chapter 2.2.3 --- Software system --- p.12 / Chapter 2.2.4 --- Communication infrastructure --- p.13 / Chapter 2.3 --- Frequency Regulations and Standards --- p.13 / Chapter 2.3.1 --- RFID frequency --- p.13 / Chapter 2.3.2 --- Standards --- p.14 / Chapter 2.4 --- Technology Comparison and RFID Applications --- p.16 / Chapter 2.4.1 --- Technology Comparison --- p.16 / Chapter 2.4.2 --- RFID Applications --- p.19 / Chapter 3 --- Research Background --- p.22 / Chapter 3.1 --- Tag-Collision Resolution Techniques for RFID systems --- p.23 / Chapter 3.1.1 --- Deterministic Collision-Resolution Technique --- p.25 / Chapter 3.1.2 --- Stochastic Collision-Resolution Technique --- p.27 / Chapter 4 --- Optimized Anti-Collision Protocol --- p.30 / Chapter 4.1 --- System Description --- p.31 / Chapter 4.2 --- Mathematical System Model --- p.35 / Chapter 4.3 --- Optimal Parameter --- p.40 / Chapter 4.3.1 --- Stochastic Shortest Path --- p.41 / Chapter 4.3.2 --- Optimal Parameter --- p.44 / Chapter 4.4 --- Performance Evaluation --- p.45 / Chapter 4.4.1 --- Initial and Optimal Policy --- p.45 / Chapter 4.4.2 --- Performance Comparison --- p.48 / Chapter 4.5 --- Summary --- p.53 / Chapter 5 --- Unknown Tag Set Anti-Collision Protocol --- p.54 / Chapter 5.1 --- Protocol Description --- p.55 / Chapter 5.1.1 --- System Model --- p.55 / Chapter 5.1.2 --- Tag Estimation --- p.57 / Chapter 5.2 --- Performance Evaluation --- p.62 / Chapter 5.3 --- Summary --- p.67 / Chapter 6 --- Conclusion and Future Work --- p.68 / Chapter 6.1 --- Conclusion --- p.68 / Chapter 6.2 --- Future Work --- p.70 / Bibliography --- p.73

Gao, Xin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 73-74). / Abstracts in English and Chinese. / Table of Contents --- p.vii / Table of Figures --- p.ix / List of Abbreviations --- p.xiii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Overview --- p.1 / Chapter 1.2 --- Original Contributions --- p.5 / Chapter 1.3 --- Chapter Outlines --- p.5 / Chapter Chapter 2 --- Fundamentals of Stepped-impedance Resonators --- p.7 / Chapter 2.1 --- Introduction --- p.7 / Chapter 2.2 --- Structures of Stepped-impedance Resonators --- p.8 / Chapter 2.3 --- Resonance Conditions Analysis --- p.10 / Chapter 2.4 --- Spurious Resonance Frequencies --- p.12 / Chapter 2.5 --- Applications of Stepped-impedance Resonator Techniques --- p.14 / Chapter Chapter 3 --- Coupled line and Partially Coupled Stepped-impedance Coupled Lines --- p.15 / Chapter 3.1 --- Introduction --- p.15 / Chapter 3.2 --- Coupled Line Model --- p.17 / Chapter 3.3 --- Analysis of Coupled Line --- p.20 / Chapter 3.4 --- Analysis of Partially Coupled Stepped-impedance Coupled Lines --- p.28 / Chapter 3.5 --- Dual Band Properties of Partially Coupled Stepped-impedance Coupled Lines --- p.29 / Chapter Chapter 4 --- A Novel Dual Band Balun Using Partially Coupled Stepped-impedance Coupled Lines --- p.30 / Chapter 4.1 --- Introduction --- p.30 / Chapter 4.2 --- Theory of Balun --- p.31 / Chapter 4.3 --- Analysis of the Proposed Dual Band Baluns --- p.37 / Chapter 4.4 --- Design Case Study for the Proposed Dual Band Balun --- p.43 / Chapter 4.5 --- Discussion --- p.50 / Chapter 4.6 --- Fabrication of a Balun Working at 900 MHz and 1.8 GHz --- p.56 / Chapter Chapter 5 --- Conclusion --- p.61 / Appendix 1 --- p.62 / Bibliography --- p.73

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The research background of this thesis is Radio Frequency Identification (RFID), where an object can be identified remotely using electromagnetic waves. The focus of this thesis is on the in-depth investigation of two major problems in the RFID deployment in supply chain applications, namely the reader collision problem in dense reader environments and the tag performance problem in hostile environments. To resolve the reader collision problem, the first part of this thesis offers a comprehensive path loss model for the analysis of the positioning of RFID reader antennas. Simulation software was developed to predict the signal strength at a certain distance from a reader antenna in a dense reader environment. This simulation software was also utilised to publish insights and research results in four major areas, which are: (i) Investigation on the sources of error in RFID simulation, to provide sensible and meaningful simulation results before actual deployment of RFID readers. (ii) The development of the idea of reader synchronisation, mainly to address the strict regulations imposed on the deployment of RFID readers in Europe. (iii) The determination of the threshold value for second carrier sensing in RFID, to enable the proper enforcement of second carrier sensing to avoid tag confusion in dense reader environments. (iv) The examination of Specific Absorption Rate (SAR) to ensure human safety in a dense RFID reader environment. The second part of this thesis addresses the RFID tag performance problem in hostile environments. The focus is on the development of HF and UHF tags, from the initial tag antenna design, tag antenna simulation, tag antenna prototyping and measurement, to the manufacturing of fully functional RFID tags at laboratory standards by combining RFID chips on to tag antennas. Though there are existing commercial grade HF and UHF RFID tags, they are mostly aimed at pallet level applications and are not suitable for deployment in hostile environments. The study cases presented in this thesis are mostly industrially driven, where there is a need to design specialty HF and UHF tag antennas. With a strong foundation in the development of HF and UHF RFID tags for various industrially driven applications, the research then concentrates on the development of a novel dual-frequency RFID antenna, which operates in both the HF and UHF regions. This dual-frequency RFID tag antenna embraces the benefits of both the HF and UHF tag antenna, which enable it to have a good read range while operating in environments that pose difficulties for RFID technology, for example applications in which ionised liquid is present, such as in cases of wine or bottled drinks. Several methodologies were used to develop a dual-frequency antenna, including the merging of HF and UHF antennas, and having a UHF resonance point on a typical HF antenna. With the successful development of an original dual-frequency antenna, the research was then expanded to miniaturise this dual-frequency antenna. The benefits of RFID deployment in supply chains are undoubtedly massive, though there are still issues and challenges to be resolved before a world-wide adoption is possible. This thesis contributes in recommending various reader antenna positioning and deployment techniques, and also contributes in developing HF tag antennas and UHF tag antennas for hostile environments, and a novel dual-frequency tag antenna to progress towards the aim of ubiquitous object identification. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1330885 / Thesis (Ph.D.) - University of Adelaide, School of Electrical and Electronic Engineering, 2008

The spatial frequency doubling illusion (FDI) occurs when the contrast of a low spatial frequency sinusoidal grating is modulated at high temporal frequencies – its apparent spatial frequency increases. Earlier suggestions were that the FDI is generated by a specific class of retinal ganglion cells, which are preferentially lost in the early stages of glaucoma. Based on this linking theory, frequency doubling perimetry (FDP) was developed and several clinical reports confirmed its high efficiency in diagnosing early glaucomatous vision loss. However, this linking theory is not universally accepted and newer suggestions posit that the illusion arises because of temporal frequency related difficulties in temporal phase encoding ability. This thesis psychophysically examines the spatiotemporal characteristics of both the FDI and temporal phase encoding ability with achromatic and equi-luminant (both red-green (RG) and blue-yellow (BY)) gratings at a range of spatiotemporal parameters including those eliciting the FDI. (For complete abstract open document)

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A new glucose affinity sensor based on a homogeneous fluorescence resonance energy transfer (FRET) assay system was developed to monitor the competitive binding between concanavalin A (ConA) and dextran. The FRET quenching kinetics of the donor were analyzed from frequency-domain (FD) measurements as functions of both glucose and acceptor-protein concentrations using a Förster-type decay kinetics model. The results showed that the FD measurements and donor decay kinetics can indicate quantitative changes in the presence of glucose at concentrations ranging from 0 to 224 mg/dL. The second set of experiments proved the feasibility of performing analyte sensing with FD lifetime spectroscopy using microsphere-based sensors in multiple scattering solutions. A well characterized pH-sensitive fluorophore was entrapped in poly(ethylene glycol) microspheres. The particles were then immersed in a buffered polystyrene solution of various pH. Measurements of phase shift and modulation of the generated and multiply scattered fluorescent light were acquired as the modulation frequency of the incident excitation light varied from 10 to 120 MHz. After the measured data were analyzed with the coupled diffusion equations, the obtained lifetimes from the scattering measurements matched values from non-scattering measurements. Lastly, a new two-speed Monte Carlo (MC) simulation was developed to predict light propagation through the sensors and thus was used to evaluate these sensors and to design these sensors for implantation. The model used random packing structure and considered geometric optics and two light propagation speeds. Experimental measurements of phase-shift and modulation of excitation light were made on a cubic phantom with non-fluorescent resin microspheres of 74 µm diameter, and compared to those computed from the MC simulation. The results showed that the mean phase shift (PS) deviation was 0.736° and the mean amplitude deviation was 42%. Quantitative changes in detected fluorescence phase-shift and modulation were investigated for microsphere diameter, volume fraction, refractive index, and fluorophore lifetime. We also found that even though the sensitivity of PS change in the presence of scattering was the same as the value without scattering, the values of PS were magnified due to the scattering effects.

The concrete maturity method can be utilized to determine in situ strength of concrete. It uses the temperature of concrete to determine a maturity index that can then be used to determine strength of concrete. However, monitoring the concrete temperature using thermocouples brings up a wiring issue, which is not advisable in an equipment and human intensive area like a construction site. One of the ways to get around this wiring issue is to use Radio Frequency Identification (RFID) technology, which is capable of transmitting information wirelessly. Previous research implemented using ultra high frequency RFID tags embedded in fresh concrete found that water could be the impediment for transmitting RFID signal from within concrete during early stages of curing. From literature it was found that lower the frequency, better the chances of the wave penetrating water. The objective of the research was to figure out whether the frequency of RFID tags has any relationship with the readability of RFID tags embedded in fresh concrete. For this investigation, low frequency, high frequency, and ultra high frequency RFID tags were tested within fresh concrete to see any difference between tags in terms of transmitting information. This experiment was carried out in a controlled space to reduce the number of variables affecting the experiment outcome. The low frequency, high frequency, and ultra high frequency RFID tags were placed within 2 in x 3 in x 2 in wooden formwork at a depth of 4 in, 8 in, and 12 in. Ready mix concrete was poured into the formwork and 3 concrete cubes were cast with the tags embedded within them. Readers that could be connected to a laptop were used to monitor and collect the time at which these RFID tags can be detected. The test showed that the RFID signals from the low frequency tags at all depths were detected as soon as concrete was poured. The Ultra High Frequency tags placed at the 4" level could be detected 15 minutes after concrete was poured. The UHF tags at the 8" level could be detected after 30 minutes. The UHF tags at the 12" level took on an average 2 hours to be detected from the vicinity of the formwork. The greater the depth at which the ultra high frequency tag was buried the longer it took for it to be detected. The high frequency tags could be detected only at the 4" level. The reason the performance of the HF card degraded in concrete could be because it uses an aluminum foil antenna which is more susceptible to the environment changing the relative permeability. A copper wire antenna could have fared better in this condition, increasing the chances of detecting the tag. Moreover a passive tag was used. The read range and chances of detection could have been increased had an active tag been used. The power of the reader that was used was also very less which might have contributed to the tag not being detected. Among the tags that were used in the experiment it was found that low frequency tags was the tag that could be detected the earliest after concrete was poured into the forms. However, the maximum read range of the tag observed in the experiment was 20" which is too small a distance to be used on an actual construction site.

Abstract Spread spectrum technique modifies the signal spectrum to spread it out and increase its bandwidth. There are two major methods in spread spectrum technique: direct sequence and frequency hopping. The resistance capability of jamming signal for frequency hopping system is better than that for direct sequence system. Two types of frequency hopping techniques can be distinguished. In ¡§fast frequency hopping¡¨ the period of a frequency-hop is smaller than a data symbol-period while in ¡§slow frequency hopping¡¨ the period of a frequency-hop is larger than a data symbol-period. Fast frequency hopping systems have the advantages that the error correction codes are not needed and diversity can be applied. The disadvantage of fast frequency hopping system is that coherent data detection is not possible because of phase discontinuities. Traveling wave tube amplifier is often used in satellite communications. It has nonlinear characteristics which can be classified as nonlinear amplitude and phase distortions toward the output signals. Certain backoff input power makes the amplifier work within the linear region. However, in order to have more output power, the amplifier usually operates in the saturation region and in consequence serious nonlinear signal distortion would be introduced. In this thesis, the effect of nonlinear amplifier on a frequency hopping multiple access (FHMA) system with binary frequency shift keying is discussed. In the simulation, two types of nonlinear amplifiers, traveling wave tube amplifier and solid state power amplifier, are applied to the FHMA system. Tradeoff between power efficiency and performance degradation is determined by the index of total performance degradation, which is obtained from simulation. With known single carrier output power, third-order intermodulation, and same input power, the bit error rate performance is also analyzed.