Field-cycled proton-electron double-resonance imaging (FC-PEDRI) is a technique developed to image the distribution of free radicals in biological samples. This technique is based on the Overhauser Effect that causes an enhancement in the NMR signal by saturating the ESR resonance of unpaired electrons in the sample. FC-PEDRI requires two sources of RF irradiations. To improve the sensitivity and to reduce power deposition in samples, new dual-tuned single coil designs were needed since existing dual-tuned single-coil designs known in the literature cannot operate at two widely separated frequencies. The theory of double-tuned circuits was examined and new circuit models were developed to identify the design requirements. Four new dual-tuned RF coils were developed, namely a dual-tuned split solenoidal coil (2.5 and 78 MHz), a combined saddle-birdcage (CS-B) coil (2.5 and 110 MHz), a 3-endring (3-ER) birdcage (2.5 and 56 MHz) and a 4-endring (4-ER) birdcage (2.5 and 74 MHz). A prototype coil for each design was built for performance evaluation studies and the parameters evaluated were: the Q factors, the signal-to-noise ratio, the transmit sensitivity and the field uniformity. The performance of the NMR-mode of the 3-ER and 4-ER designs was poor because the inherently low-inductance of the birdcage meant that high-value capacitors with high dissipation factors had to be used in the fabrication. A new construction method named as the multilayer self capacitance (MLSC) technique was developed to improve the efficiency of the 4-ER design by creating efficient capacitors within the conductors of the coil itself. The unloaded Q factor of the optimised 4-ER birdcage using the MLSC technique was 267 compared to 100 when commercial capacitors were used.

Magnetic Resonance Imaging (MRI) is a widely used soft-tissue imaging modality that has evolved over the past several years into a powerful and versatile medical diagnostic tool capable of providing in-vivo diagnostic images of human and animal anatomies. Current research efforts in MRI system design are driven by the need to obtain detailed high resolution images with improved image signal-to-noise ratio (SNR) at a given magnetic field strength. Invariably, this requirement demands the development of high performance MRI radio frequency (RF) coils. However, the complexities and stringent requirements of modern clinical MRI systems necessitate the development of new modeling methodologies for the design of high performance RF coils. This dissertation addresses this need by developing a distinct Method of Moments (MoM) modeling approach suitable for the simulation of RF coils loaded with biological tissues. The unique implementation utilizes two distinct basis functions in order to collectively describe the surface current density on the RF coil, and the sum of the volume current density and the displacement current density in the associated biological tissue. By selecting basis functions with similar properties to the actual physical quantities they describe, we avoided spurious solutions normally associated with MoM based implementations. The validity of our modeling method was confirmed by comparisons with analytical solutions as well as physical measurements, yielding good agreement. Furthermore, we applied the MoM based modeling method in the design and development of a novel 4-channel receive-only RF coil for breast imaging in a clinical 1.5T system. The new coil design was inspired by the multi-channel array concept, where multiple conducting strips were arranged in an anatomically conforming profile with the intention of improving sensitivity and SNR. In addition, the coil structure featured an open breast coil concept in order to facilitate MRI-guided biopsy and patient comfort. A comparison of simulation results and actual physical measurements from the prototype RF coil demonstrated good agreement with one another. Also, imaging tests were conducted on a pair of MRI phantoms as well as on a human patient after obtaining proper authorization. The tests revealed good magnetic field homogeneity and a high SNR in the region of interest. In addition, performance comparisons between the prototype 4-channel RF coil and existing high end clinical 4-channel RF breast coils indicated an achievement of superior SNR in conjunction with very good magnetic field homogeneity. Currently, the prototype 4-channel RF coil has outperformed all existing high end clinical 4-channel RF coils used in comparison studies.

La technologie RFID UHF, également appelée RAIN RFID, est une technologie passive permettant l’identification automatique des objets. Elle comble ainsi le fossé entre les mondes physique et numérique en permettant à un objet de devenir « vivant » sur l'internet des objets grâce à des étiquettes RFID (tags) peu coûteuses et sans batterie. La technologie RFID UHF passive témoigne d’un développement significatif en raison de la croissance accélérée de dispositifs technologiques sophistiqués. Ce développement est en grande partie poussé par la chaîne d'approvisionnement et la grande distribution. Dans ces domaines, la RFID UHF passive de deuxième génération (Gen2), parmi d'autres solutions de traçage et d'identification possibles, constitue un choix logique compte tenu du faible coût des tags lorsqu’ils sont produits en gros volumes, de leur facilité d'impression et de l’absence de batterie.La principale préoccupation des revendeurs détaillants est la disponibilité du produit. Celle-ci peut être affectée par l’existence d’erreurs liées à la visibilité (écarts de stockage, vol, perte) et d’erreurs humaines. Il est donc nécessaire d'améliorer la visibilité et d'automatiser le processus. Malgré ses avantages, le déploiement de la technologie RFID dans la grande distribution est toujours confronté à de nombreux obstacles et défis. Dans cette thèse, nous nous sommes attachés à répertorier toutes les technologies de composants et de lecteurs proposées sur le marché ou encore à l’état de prototype, puis, après avoir identifié et analysé les différents défis liés à ce domaine particulier d’application, à élaborer et à tester de nouvelles solutions.En premier lieu, les distances maximales de lecture des tags passifs sont évaluées dans différents environnement afin d’identifier les facteurs les impactant. A l’issue de cette étude, une méthode de caractérisation alternative est proposée pour contrôler les performances des tags et identifier les objets tagués ayant de faibles performances. Deuxièmement, nous nous appuyant sur cette méthode pour proposer une nouvelle solution d’amélioration de la détection. Les algorithmes conçus et réalisés pour traduire cette solution permettent aux lecteurs de négocier leurs configurations avec l’environnement et entre eux. Enfin, un nouvel algorithme de localisation est proposé afin d’améliorer la précision. Son élaboration et son implémentation sont basées sur l’exploitation de la réponse des tags identifiés comme les plus fiables du milieu. Les solutions proposées sont particulièrement avantageuses car universelles, compatibles avec les lecteurs du marché et n’ajoutant aucun coût au matériel utilisé pour la détection. / UHF RFID technology, also known as RAIN RFID, is a passive technology that enables the automatic identification of items. Thus, it bridges the gap between the physical and digital worlds by allowing an item to become alive on the Internet of things thanks to inexpensive and battery-free RFID tags. Passive UHF RFID technology has witnessed a significant development due to the accelerated growth of sophisticated technological devices. This development is largely driven by the supply chain and the retail industries. Passive UHF RFID Gen2, among other tracing and identification solutions, is the logical choice given the low costs of large-volume tags, ease of printing and being battery-free, the need for maintenance is completely eliminated.The main concern of resellers, the withdrawal of the product, is mainly affected by errors related to visibility (stock gap, theft, loss) and human errors. It is, therefore, necessary to improve visibility and automate the process. Despite its advantages, RFID deployment in supermarkets is still facing many obstacles and challenges. In this thesis, we focus on technological availability by defining and analyzing the different challenges and possibly proposing the appropriate solutions.First, the maximum reading distances of passive tags are evaluated in different environments in order to identify the factors impacting them. At the end of this study, an alternative characterization method is proposed to control tag performance and identify tagged objects with poor performance. Secondly, we will use this method to propose a new solution to improve detection. The algorithms behind this solution allow readers to negotiate their configurations with the environment and with each other. Finally, a new location algorithm is proposed to improve accuracy. This algorithm is based on the exploitation of the answers of the reliable tags of the medium. The proposed solutions are universal, compatible with market readers and add no cost to the hardware used for detection.

<p><p>This report shows a survey of sate of the art different large signal RF measurement systems. Such measurement systems are discussed in detail with respect to their architecture, method of measurement, calibration, accuracy, dynamic range and bandwidth. Finally, a RF measurement system for large signal was designed and implemented. This measurement system was based on a tuned receiver. Harmonic distortion type measurements were taken by this system and time domain waveforms were reconstructed using external software.</p></p>

<p>SAAB Aerotech division FGR in Arboga builds and develops equipment and components used in both military and civilian applications. To build a test system for a specific project that SAAB is responsible for requires a simple signal generator that can provide a pulse modulated signal. The need to buy a new advanced signal generator for example from Agilent is not as profitable as the instrument is expensive and contains features that SAAB does not require in their applications and test systems. That was the reason why SAAB offers two students a thesis where the goal is to construct a signal generator in accordance with what SAAB requests.</p><p>This thesis contains several different phases. The first step was a meeting with our supervisor Mats Bergman and by reading the data sheets for components to be used in the project, with these information and specifications that we have received from SAAB we started to construct the signal generator.</p><p>What we did during the construction work was to simulate and draw a schematic to be able to design the circuit board. Simulation was done both in software and on laboration board. The card is then ordered from a circuit board manufacturer in Bulgaria. On the finished card the components will be fitted. Then the card will plugged in into a rack and then presented finished as a signal generator that can be used in a test system.</p><p>The final results of all phases are satisfactory in the part of design and laboratory work. The finished mother board was tested and test results corresponded well with the theory. The final results will be presented with a spoken presentation at the University of Gävle and at SAAB Aerotech in Arboga division FGR</p> / <p>SAAB Aerotech avdelning FGR i Arboga bygger och utvecklar en hel del utrustningar och komponenter som används både i militära och civila applikationer.</p><p>För att bygga ett testsystem till ett specifikt projekt som SAAB ansvarar för krävs en enkel signalgenerator som kan ge en pulsmodulerad signal. Behovet av att köpa en ny och avancerad signalgenerator från till exempel Agilent är inte så lönsamt eftersom instrumentet kostar mycket och innehåller funktioner som SAAB inte alls behöver i sina applikationer och testsystem. Detta var orsaken till varför SAAB erbjuder två studenter ett examensarbete där målet är att konstruera en signalgenerator enligt SAABs önskemål .</p><p>Examensarbetet innehåller flera olika faser. Det som först gjordes är en faktainsamling genom ett möte med vår handledare Mats Bergman samt genom att läsa datablad för komponenterna som ska användas i projektet. Därefter har vi med den informationen samt kravspecifikationen som vi har fått från SAAB påbörjat arbetet med att konstruera signalgeneratorn.</p><p>Det som gjordes under konstruktionsarbetet var dels att simulera och rita schema för att kunna designa kretskortet. Simulering gjordes både i mjukvara och på laborationsplatta. Kortet beställdes från en kretskortstillverkare i Bulgarien. På det färdiga kortet ska komponenter monteras. Därefter monteras kortet in i en rack för att sedan presenteras som en färdig signalgenerator som kan användas i ett testsystem.</p><p>Det slutgiltiga resultatet av momenten för kortkonstruktionen och laborationer var tillfredställande. Det färdiga kortet testades och resultaten från dessa tester stämde bra överens med teorin. Den färdiga signalgeneratorn kommer att presenteras med en muntlig presentation dels på Högskolan i Gävle och SAAB Aerotech i Arboga avd FGR.</p>

Electronic article surveillance (EAS) is widely used in shops and libraries together with an RF-tag attached to the goods or books in order to prevent shoplifting. By implementing the addition of a moisture sensor to the RF-tag, other functions become possible, including the ability to use as an alarm with regards to frozen goods, which have been shipped but which have melted and have, subsequently, refrozen. In- relation to care for the elderly, one time-consuming step involves checking whether there is the necessity for a change of diaper and this can, instead, be based on an RF-tag with an EAS-system alarm. A preliminary investigation was made using the moisture sensors, which involved how the resistance changes when liquid and/or heat is applied. A simulation of the LCCR circuit (RF-tag with the sensor) was conducted in order to determine how the resonance frequency changes for different resistances levels. When the moisture sensors are applied to the RF-tag with the correct resistance no alarm will be triggered, but will be triggered when water is added to the moisture sensor. In order for the tag to be able to induce energy from the transmitter in the EAS-system the resistance must be less than ten ohms in relation to the entire tag. Results show that the implementation of the sensor on the RF-tag is possible and that it works in a satisfactory manner. / Elektroniska varularm EAS (Electronic article surveillance) är vida använt i butiker och bibliotek tillsammans med RF-tagg som är fäst på varor böcker för att förhindra snatteri. Genom att implementera fuktsensor till RF-taggen kan den få andra funktioner som då kan användas till larm om frysvaror fraktas har tinat men fryst igen, samt till äldrevården där ett tidsdödande moment är att hela tiden kontrollera om vårdtagaren behöver byta blöja. I stället kan RF-taggen med EAS-systemet larma. Förundersökning gjordes med fuktsensorn som är en sensor för hur resistansen ändras när vätska och värme förs på den. Simulering av LCCR krets (RF-tagg med sensor) gjordes för att se hur resonansfrekvensen ändras vid olika resistansnivåer. När fuktsensorn är applicerad på RF-tagg med rätt resistans triggas inte alarm, men däremot när vatten förs på fuktsensorn. För att taggen ska kunna inducera energin från sändaren i EAS-system måste resistansen vara lägre än tio ohm på hela RF-taggen. Resultatet visar att implementering av sensor på RF-tagg är möjlig och fungerar.

This work aims to demonstrate the design and simulation of a Radio Frequency (RF) energy-harvesting circuit, from receiving antenna to the point of charge collection. The circuit employs a custom-designed antenna based around Koch fractal loops, selected for their small physical size, good multiband behaviour and ease of size scalability, as well as a power-efficient seven-element Greinacher rectification section designed to charge a super-capacitor or rechargeable battery for later use. Multiple frequency bands are tapped for energy and this aspect of the implementation was one on the main focus points. The bands targeted for harvesting in this thesis will be those that are the most readily available to the general Canadian population. These include Wi-Fi hotspots (and other 2.4GHz sources), as well as cellular (850MHz band), Personal Communications Services (1900MHz band) and WiMax (2.3GHz) network transmitters.

This report shows a survey of sate of the art different large signal RF measurement systems. Such measurement systems are discussed in detail with respect to their architecture, method of measurement, calibration, accuracy, dynamic range and bandwidth. Finally, a RF measurement system for large signal was designed and implemented. This measurement system was based on a tuned receiver. Harmonic distortion type measurements were taken by this system and time domain waveforms were reconstructed using external software.

SAAB Aerotech division FGR in Arboga builds and develops equipment and components used in both military and civilian applications. To build a test system for a specific project that SAAB is responsible for requires a simple signal generator that can provide a pulse modulated signal. The need to buy a new advanced signal generator for example from Agilent is not as profitable as the instrument is expensive and contains features that SAAB does not require in their applications and test systems. That was the reason why SAAB offers two students a thesis where the goal is to construct a signal generator in accordance with what SAAB requests. This thesis contains several different phases. The first step was a meeting with our supervisor Mats Bergman and by reading the data sheets for components to be used in the project, with these information and specifications that we have received from SAAB we started to construct the signal generator. What we did during the construction work was to simulate and draw a schematic to be able to design the circuit board. Simulation was done both in software and on laboration board. The card is then ordered from a circuit board manufacturer in Bulgaria. On the finished card the components will be fitted. Then the card will plugged in into a rack and then presented finished as a signal generator that can be used in a test system. The final results of all phases are satisfactory in the part of design and laboratory work. The finished mother board was tested and test results corresponded well with the theory. The final results will be presented with a spoken presentation at the University of Gävle and at SAAB Aerotech in Arboga division FGR / SAAB Aerotech avdelning FGR i Arboga bygger och utvecklar en hel del utrustningar och komponenter som används både i militära och civila applikationer. För att bygga ett testsystem till ett specifikt projekt som SAAB ansvarar för krävs en enkel signalgenerator som kan ge en pulsmodulerad signal. Behovet av att köpa en ny och avancerad signalgenerator från till exempel Agilent är inte så lönsamt eftersom instrumentet kostar mycket och innehåller funktioner som SAAB inte alls behöver i sina applikationer och testsystem. Detta var orsaken till varför SAAB erbjuder två studenter ett examensarbete där målet är att konstruera en signalgenerator enligt SAABs önskemål . Examensarbetet innehåller flera olika faser. Det som först gjordes är en faktainsamling genom ett möte med vår handledare Mats Bergman samt genom att läsa datablad för komponenterna som ska användas i projektet. Därefter har vi med den informationen samt kravspecifikationen som vi har fått från SAAB påbörjat arbetet med att konstruera signalgeneratorn. Det som gjordes under konstruktionsarbetet var dels att simulera och rita schema för att kunna designa kretskortet. Simulering gjordes både i mjukvara och på laborationsplatta. Kortet beställdes från en kretskortstillverkare i Bulgarien. På det färdiga kortet ska komponenter monteras. Därefter monteras kortet in i en rack för att sedan presenteras som en färdig signalgenerator som kan användas i ett testsystem. Det slutgiltiga resultatet av momenten för kortkonstruktionen och laborationer var tillfredställande. Det färdiga kortet testades och resultaten från dessa tester stämde bra överens med teorin. Den färdiga signalgeneratorn kommer att presenteras med en muntlig presentation dels på Högskolan i Gävle och SAAB Aerotech i Arboga avd FGR.

This thesis investigated the microstructure and mechanical property of RRR( high purity) and RG (low purity) niobium (Nb) sheet material. RRR Nb is used in the fabrication RF cavities. Our method involves processing bulk niobium by equal channel angular extrusion (ECAE) and then cross rolling to obtain sheets. This work is a study of the effect different thermomechanical processing variables have on the microstructure niobium sheets. Recrystallization behaviors strongly depended on the purity levels. Tensile tests on sheets clearly indicated the anisotropy in the sheet material. The ductility of the sheet was found to be the largest at an angle of 45o to the rolling direction. There was no apparent relationship observed in the yielding behavior in the different samples. The formability of the sheet measured by the anisotropy ratio suggested a strong dependence of anisotropy on texture. Texture results obtained show that different routes of ECAE can lead to variety of textures in final sheet material. Correlations between the microstructure and the ECAE routes suggest that effective control of microstructure is possible by the thermomechanical steps followed in this study.