Tesi sul tema "Radiofrequency measurements"

An increasing number of power plants in Scandinavia are beginning to use biofuel instead of coal or oil. The material in the new fuel is a mixture of woodchips, mostly Pine, Spruce and Salix, bark, GROT (tops and branches from felling waste) and sawdust from sawmills. It is heterogeneous, having a moisture content varying from 15% up to 65%. The moisture content affects the combustion of the fuel and therefore its commercial value. The industry is now interested in obtaining a method for measuring the moisture content of biofuel, quickly and reliably; preferably on delivery at the power plant. The measuring technique presented in this thesis is the first reported in the literature capable of measuring the moisture content of a large sample of such an heterogeneous material as biofuel. The equipment is today calibrated for a sample volume of 0.1 m3. A radio frequent signal is supplied from an antenna and penetrates the biofuel. Its reflection is modeled using partial least squares. As part of the work presented in this thesis, a new type of measuring rig and an analysis method for measurement of the moisture content of large samples of heterogeneous material have been developed. A statistical model for moisture content measurements of five different biofuel materials using radio waves has been built, having a root mean square error of prediction of 2.7. The interactions between biofuels and radio frequent signals have been demonstrated, indicating a variation of the reflection with varying types of biofuel material and variation in the reflection and delay of the signal with varying moisture content.

Les propriétés des ondes térahertz (THz) offrent des perspectives pour relever les défis sociétaux du XXIᵉ siècle dans les domaines de la santé, de la sécurité et de l'énergie. Cette thèse examine l'utilisation de couches minces de La0.7Sr0.3MnO3 (LSMO) déposées sur silicium pour réaliser des détecteurs THz à température ambiante, en exploitant la variation de leur résistance électrique. Les détecteurs sont associés à des antennes planaires, exigeant une adaptation d’impédance optimale entre l’antenne et la couche mince. Dans ce but, les couches LSMO et leurs contacts électriques (Au/LSMO) ont été caractérisés en courant continu et dans le domaine radiofréquence (10 MHz à 325 GHz). En courant continu, l'étude révèle que de fortes résistances électriques de contact introduisent des comportements non-linéaires qui dégradent la lecture des détecteurs. Un recuit thermique associé à une géométrie adaptée du détecteur a permis de ramener les résistances de contact à un niveau négligeable, avec une résistance spécifique de 10⁻⁵ Ω·cm². L’analyse radiofréquence effectuée sur des lignes coplanaires chargées par du LSMO a montré que l’impédance du LSMO est réelle et que les résistances électriques de contact sont négligeables à ces fréquences. Ces résultats ont permis de concevoir des détecteurs couplés à une lentille diélectrique et de les tester à 640 GHz et 2.52 THz. Les performances mesurées se montrent prometteuses comparées à l’état de l’art, avec un NEP électrique de quelques pW/√Hz (limité par le bruit de phonons) et un temps de réponse de 0.1 ms. Le NEP optique, avoisinant 600 pW/√Hz dans la bande passante, pourrait être optimisé par une meilleure absorption du rayonnement
The properties of terahertz (THz) waves offer promising perspectives for addressing 21st-century societal challenges in the fields of health, security, and energy. This thesis investigates the use of La0.7Sr0.3MnO3 (LSMO) thin films deposited on silicon for the development of THz detectors operating at room temperature, by exploiting the variation in their electrical resistance. The films are coupled with planar antennas, requiring optimal impedance matching between the antenna and the thin film. In this context, the LSMO layers and their electrical contacts (Au/LSMO) were characterized in direct current and in the radiofrequency domain (10 MHz to 325 GHz). In direct current, the study reveals that high contact resistances introduce nonlinear behaviors that degrade detector reading. Thermal annealing combined with an optimized detector geometry allowed for contact resistances to be reduced to a negligible level, achieving a specific contact resistance of 10⁻⁵ Ω·cm². The radiofrequency analysis performed on coplanar lines loaded with LSMO showed that the LSMO impedance is real with no contact resistances. These findings enabled the design of detectors coupled with a dielectric lens, which were tested at 640 GHz and 2.52 THz. The performances are promising compared to the state of the art, with an electrical NEP of a few pW/√Hz (limited by phonons noise) and a response time of 0.1 ms. The optical NEP, around 600 pW/√Hz in the bandwidth, could be optimized through enhanced radiation absorption

Significant concern has been expressed regarding the potential link between various health problems (eg cancer) and exposure to radiofrequency (RF) electromagnetic energy (EME). In particular mobile phone base stations, commonly referred to as radio base stations (RBS) have attracted public attention. With the number of these RBS increasing around the world, questions have been raised about the fields generated by these types of equipment. In particular the public and the industry are interested in the strengths of these fields and how they compare to the regulatory standards of various countries. There are two approaches that can be used to determine the field strengths generated by the RF EME transmitting installations. They can be physically measured using expensive and sophisticated equipment, requiring a significant level of technical knowledge, or alternatively, they can be modelled theoretically using complex simulations. Due to the number of installations that already exist, and the rate at which their numbers are increasing, the physical measurement of these sites may be considered impractical and expensive. Therefore, simulation of the RF EME fields from these installations is often the preferred option. In Australia, the industry code C564:2011 – Mobile Phone Base Station Deployment (CA 2011) ‐ requires that site RF EME assessments for Mobile Phone Radiocommunications Infrastructure must be completed in accordance with the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) prediction methodology Technical Report – Radio Frequency EME Exposure Levels – Prediction Methodologies (Bangay 2002). The purpose of the assessments is to provide affected persons in the community with a reliable, objective and near worst case, line‐of‐sight estimate of the maximum levels of RF EME likely to be emitted by the proposed or upgraded mobile phone base station installation, for full‐power operation without producing a gross over‐estimate (CA 2011). The aim of this study is to test, using actual field measurements, whether the assumptions made in the ARPANSA prediction methodology result in achieving the stated purpose of the assessments as explained above. This study compares the calculated RF EME levels by a number of commercial software packages, for a number of service providers and technology types (i.e. WCDMA850, GSM900 and 1800 and UMTS2100), at a number of locations, to the measured levels for those same locations. As part of the measurement component of this study the applicability of a number of spatial averaging assessment techniques will also be considered. In particular the 3, 6 and 9 point spatial averaging techniques recommended in the IEC assessment standard and a 7 point spatial averaging technique, recommended by the Australian Radiation Protection Agency (ARPANSA) are compared and evaluated. The main findings of this study are: 1. Overall, the ARPANSA prediction methodology does achieve its stated purpose. 2. The largest overestimation of the RF EME levels by simulation was 20.92 dB (124 times). Whilst, this appears to be quite large the largest simulated level was 624 times below the general public limit. 3. The use of a single measurement point to determine RF EME levels for a given location could result in an under estimation of the levels beyond the ±3 dB uncertainity of the measurements (‐8.18 dB). If completing measurements to confirm compliance to the regulatory limits it would be better to use the 9 pt averaging technique when the 1pt measured level is greater than 30% of the applicable limit. 4. Comparisons between the measurement and simulation results revealed that they do not always closely align with each other. However, in all cases where this occurred, the simulated levels did not under estimate the measured levels by more than 0.82 dB beyond the combined uncertainty of the measurements and simulations.

Las exigentes tolerancias de alineación en los componentes de los futuros colisionadores lineales de partículas requieren el desarrollo de nuevas técnicas de alineación más precisas que las existentes. Este es el caso del Colisionador Lineal Compacto (Compact Linear Collider, CLIC), cuyos objetivos altamente restrictivos de alineamiento alcanzan los 10 um. Para poder lograr el máximo rendimiento del acelerador, es necesario que el posicionamiento de las estructuras que aceleran las partículas y de los campos que las guían cumplan las tolerancias de alineación para dirigir el haz a lo largo de la trayectoria diseñada. Dicho procedimiento consiste en relacionar la posición de los ejes de referencia de cada componente con respecto a objetos externos, o fiduciales, lo cual resulta muy tedioso y económicamente costoso. Los errores sistemáticos y aleatorios se van acumulando en cada paso del proceso y, en consecuencia, la precisión final de alineamiento es todo un desafío. En este contexto, nace el proyecto PACMAN (Particle Accelerator Components Metrology and Alignment to the Nanometre scale), subvencionado por la Unión Europea en el programa FP7 de financiación para la investigación e innovación. El objetivo principal de PACMAN es investigar, desarrollar e implementar una solución integrada alternativa que incorpore todos los pasos de alineación en una misma ubicación, con el objetivo de mejorar la precisión de alineación de los componentes de los aceleradores, en concreto: las estructuras aceleradoras, los cuadrupolos y los monitores de posición de haz. La viabilidad de las soluciones desarrolladas y la precisión de alineamiento alcanzada deben de demostrarse en un banco de pruebas utilizando componentes de CLIC. La estrategia de PACMAN para alcanzar el objetivo técnico se divide en tres pasos. El primero consiste en la fiducialización de los componentes y sus soportes. El segundo paso es el ensamblaje de los componentes en dos tipos de soporte, uno compuesto por un monitor de posición de haz y un cuadrupolo, y otro con cuatro estructuras aceleradoras, tomando como referencia su centro electromagnético. Finalmente, ambos soportes se transportan al túnel para su alineación final utilizando técnicas de hilos tensados. En esta tesis doctoral, se describe el desarrollo de una nueva técnica no destructiva para localizar los ejes electromagnéticos de estructuras aceleradoras y su validación experimental. Para ello, se ha utilizado una estructura aceleradora de CLIC conocida como TD24. Debido a la complejidad mecánica de la TD24, su difícil acceso y su diámetro medio de iris de 5.5 mm, se desarrolla una nueva técnica denominada en esta tesis como 'el método perturbativo' y se realiza una propuesta experimental de validación. El estudio de viabilidad de este método, cumpliendo con los requisitos impuestos de precisión en la medida de 10 um, ha sido realizado con una campaña extensa de simulaciones de campos electromagnéticos en tres dimensiones utilizando la herramienta de software conocida como HFSS. Los resultados de simulación han permitido el desarrollo de un algoritmo muy completo de medidas y han proporcionado las especificaciones técnicas para el diseño conceptual de un banco de pruebas para la medida de los ejes electromagnéticos de la TD24. El preciso ensamblaje del banco de pruebas y sus correspondientes calibraciones, la incorporación de nuevos tratamientos de las medidas en el algoritmo final y la caracterización de fuentes de error en la medida, favorecieron la localización del centro electromagnético en la TD24 con una precisión menor a 1 um con un error estimado menor que 8.5 um, cumplimiendo con los objetivos de precisión establecidos.
In the next generation of linear particle accelerators, challenging alignment tolerances are required in the positioning of the components focusing, accelerating and detecting the beam over the accelerator length in order to achieve the maximum machine performance. In the case of the Compact Linear Collider (CLIC), accelerating structures, beam position monitors and quadrupole magnets need to be aligned in their support with respect to their reference axes with an accuracy of 10 um. To reach such objective, the PACMAN (Particle Accelerator Components Metrology and Alignment to the Nanometer Scale) project strives for the improvement of the current alignment accuracy by developing new methods and tools, whose feasibility should be validated using the major CLIC components. This Ph.D. thesis concerns the investigation, development and implementation of a new non-destructive intracavity technique, referenced here as 'the perturbative method', to determine the electromagnetic axes of accelerating structures by means of a stretched wire, acting as a reference of alignment. Of particular importance is the experimental validation of the method through the 5.5 mm iris-mean aperture CLIC prototype known as TD24, with complex mechanical features and difficult accessibility, in a dedicated test bench. In the first chapter of this thesis, the alignment techniques in particle accelerators and the novel proposals to be implemented in the future linear colliders are introduced, and a detailed description of the PACMAN project is provided. The feasibility study of the method, carried out with extensive electromagnetic fields simulations, is described in chapter 2, giving as a result, the knowledge of the theoretical accuracy expected in the measurement of the electromagnetic axes and facilitating the development of a measurement algorithm. The conceptual design, manufacturing and calibration of the automated experimental set-up, integrating the solution developed to measure the electromagnetic axes of the TD24, are covered in chapter 3. The future lines of research and developments of the perturbative method are also explored. In chapter 4, the most significant results obtained from an extensive experimental work are presented, analysed and compared with simulations. The proof-of-principle is completed, the measurement algorithm is optimised and the electromagnetic centre is measured in the TD24 with a precision less than 1 um and an estimated error less than 8.5 um. Finally, in chapter 5, the developments undertaken along this research work are summarised, the innovative achievements accomplished within the PACMAN project are listed and its impact is analysed.
En la generació pròxima d'acceleradors de partícules lineals, desafiant toleràncies d'alineament és requerit en el posicionament dels components que enfoquen, accelerant i detectant la biga sobre la longitud d'accelerador per tal d'aconseguir l'actuació de màquina màxima. En el cas del Colisionador Compacte Lineal (CLIC), accelerant estructures, monitors de posició de fes i imants necessiten ser alineats en el seu suport amb respectar a les seves destrals de referència amb una precisió de 10 um. Per assolir tal objectiu, el PACMAN (Metrologia de Components de l'Accelerador de partícules i Alineament al Nanometer Escala) projecte s'esforça per la millora de l'actual precisió d'alineament per mètodes nous en desenvolupament i eines, la viabilitat dels quals hauria de ser validada utilitzant els components de CLIC importants. Aquesta tesi concerneix la investigació, desenvolupament i implementació d'un nou no-destructiu tècnica interna, va referenciar ací mentre 'el mètode de pertorbació' per determinar les destrals electromagnètiques d'accelerar estructures mitjançant un cable estès, actuant com a referència d'alineament. De la importància particular és la validació experimental del mètode a través del 5.5 mm iris-roí obertura prototipus de CLIC sabut com TD24, amb característiques mecàniques complexes i accessibilitat difícil, en un banc de prova dedicat. En el primer capítol d'aquesta tesi, les tècniques d'alineament en acceleradors de partícules i les propostes novelles per ser implementades en el futur colisionador lineal és introduït, i una descripció detallada del projecte PACMAN és proporcionat. L'estudi de viabilitat el mètode de pertorbació, va dur a terme amb simulacres de camps electromagnètics extensos, és descrit dins capitol 2, donant com a resultat, el coneixement de la precisió teòrica esperada en la mida de les destrals electromagnètiques i facilitant el desenvolupament d'un algoritme de mida. El disseny conceptual, fabricació i calibratge del conjunt experimental automatitzat-amunt, integrant la solució desenvolupada per mesurar les destrals electromagnètiques del TD24, és cobert dins capitol 3. Les línies futures de recerca i desenvolupaments del mètode és també va explorar. Dins capitol 4, la majoria de resultats significatius van obtenir d'una faena experimental extensa és presentada, analitzat i comparat amb simulacres. La prova-de-el principi és completat, l'algoritme de mida és optimitzat i el centre electromagnètic és mesurat en el TD24 amb una precisió menys d'1 um i un error calculat menys de 8.5 um. Finalment, dins capitol 5, els desenvolupaments empresos al llarg d'aquesta faena de recerca és resumit, les consecucions innovadores van acomplir dins del projecte PACMAN és llistat i el seu impacte és analitzat.
Galindo Muñoz, N. (2018). Development of direct measurement techniques for the in-situ internal alignment of accelerating structures [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/100488
TESIS

Cette thèse s’inscrit dans le cadre d’un projet visant à développer un robot mobile autonome capable de réaliser des tâches spécifiques dans une zone préalablement définie par l’utilisateur. Afin de faciliter la mise en œuvre du système, des balises radiofréquences fournissant des mesures de distance par rapport au robot sont disposées au préalable autour du terrain. Le déploiement du robot s’effectue en deux phases, une première d’apprentissage du terrain, puis une seconde, où le robot effectue ses tâches de façon autonome. Ces deux étapes nécessitent de résoudre les problèmes de localisation et de localisation et cartographie simultanées pour lesquels différentes solutions sont proposées et testées en simulation et sur des jeux de données réelles. De plus, afin de faciliter l’installation et d’améliorer les performances du système, un algorithme de placement des balises est présenté puis testé en simulation afin de valider notamment l’amélioration des performances de localisation
This thesis is part of a project which aims at developing an autonomous mobile robot able to perform specific tasks in a preset area. To ease the setup of the system, radio-frequency beacons providing range measurements with respect to the robot are set up beforehand on the borders of the robot’s workspace. The system deployment consists in two steps, one for learning the environment, then a second, where the robot executes its tasks autonomously. These two steps require to solve the localization and simultaneous localization and mapping problems for which several solutions are proposed and tested in simulation and on real datasets. Moreover, to ease the setup and improve the system performances, a beacon placement algorithm is presented and tested in simulation in order to validate in particular the improvement of the localization performances

Human detection and identification has been constituting a fundamental application in everyday life, and it is assuming an increasing importance both within the commercial world and the scientific community. The applications cover a variety of different areas, such as security and surveillance, rescue/recovery of troubled people, medicine and gait analysis. Among the plenty of employed technologies, over the last few years, radar and ultrasound systems are gaining an increasing interest in human detection/identification scenario. They can effectively work in particular environments and situations where other systems may fail, like in the darkness, in smoky or foggy areas, or through not transparent obstacles. Many radar and ultrasound systems for human detection exploit Doppler and micro-Doppler effects to analyse the target motion. The micro-Doppler effect is a variant of the Doppler phenomenon which accounts also for micro-motions of the target superimposed to the bulk motion. Hence, it can be deployed to record the micro-Doppler characteristics of different moving targets, commonly referred as micro-Doppler signature. Human moving targets exhibit very distinctive and unique micro-Doppler signatures, which, if properly analysed, may be used to carry out human target recognition and classification tasks. Aim of this dissertation is to provide a general and technology independent measurement approach suitable for human identification purposes. The approach is a list of elementary blocks covering the measurement device definition and setup, the micro-Doppler signature acquisition and the algorithm for signatures analysis. In order to test the procedure, several experimental trials to collect micro-Doppler signatures have been performed, both in the ultrasonic and radio frequency domain. A novel algorithm has been also designed and developed to extract some particular features from the acquired signatures, to be used for target classification. Recognition performance has been assessed as a function of some key algorithm parameters to investigate the level of robustness of the proposed features. Results show that high level recognition performance can be achieved for different human activities and subjects, both employing ultrasounds and radio-frequency waves.
Il rilevamento e l'identificazione di persone rappresenta un'applicazione fondamentale nella vita di ogni giorno, e per questo sta assumendo un'importanza ed un interesse crescente all'interno del mondo commerciale e della comunità scientifica. Tra le innumerevoli applicazioni pratiche, si annoverano la sicurezza e la sorveglianza, il recupero ed il soccorso di persone in situazioni di emergenza, ed in medicina per la diagnosi di patologie posturali e non. Tra la vastità di tecnologie impiegate, negli ultimi anni i sistemi ad ultrasuoni e radar stanno catturando un interesse sempre maggiore nello scenario dell'identificazione ed il rilevamento umano. Tali tecnologie infatti possono operare in particolari situazioni ambientali non adatte ad altre sistemi, come ad esempio, in presenza di fumo e nebbia, o in aree buie, oppure attraverso barriere non trasparenti come muri e vegetazione. Molti sistemi radar sono progettati per sfruttare gli effetti Doppler e micro-Doppler per analizzare il movimento del target da rilevare. In termine micro-Doppler rappresenta una variante dell'effetto Doppler che considera ulteriori micro-movimenti del target, che possono essere sovrapposti al moto principale. Può essere quindi impiegato per rilevare le caratteristiche micro-Doppler, di diversi target in movimento. Tali caratteristiche, dette anche signatures micro-Doppler, si dimostrano essere una peculiarità unica e distintiva per quanto riguarda il movimento umano. Lo scopo della tesi è quello di fornire un approccio di misura che sia generale ed indipendente dalla particolare tecnologia, da usarsi per applicazioni riguardanti l'identificazione di umani. L'approccio prevede una lista di blocchi elementari, riguardanti la scelta del dispositivo e dell'ambiente di misura, l'acquisizione di signatures micro-Doppler e lo sviluppo di un algoritmo per l'analisi e la classificazione delle signatures. La procedura è stata quindi testata sia nel caso si impieghi una tecnologia ad ultrasuoni, che una tecnologia radar. È stato inoltre sviluppato un algoritmo innovativo per estrarre un insieme di parametri dalle signatures acquisite, per poi essere usati con lo scopo di classificare i target umani analizzati. Le prestazioni della procedura di riconoscimento sono state valutate in funzione di alcuni parametri chiave dell'algoritmo sviluppato, al fine di valutarne robustezza ed affidabilità. I risultati ottenuti mostrano un alto livello di riconoscimento positivo, per diversi target umani ed attività analizzate, e sia nel caso si impieghino onde ultrasonore che a radiofrequenza.

La supraconductivité induite par effet de proximité dans du graphène CVD macroscopique décoré de nanoparticules d'étain (G/Sn) est le thème central de cette thèse. Dans ce manuscrit, deux projets expérimentaux sont présentés. Le premier de ces projets a consisté à développer et étudier un nouveau matériau manipulable et flexible au sein duquel les corrélations supraconductrices s'étendent à des échelles macroscopiques. Ce matériau est un film composite qui résulte de l'empilement de trois ingrédients originaux: un film fin de parylène d'une épaisseur de quelques micromètres, une monocouche de graphène de plusieurs centimètres carrés et un film discontinu métallique obtenu par démouillage naturel de l'étain en surface du graphène.Des mesures de transport à basses températures ont permis de mettre en évidence l'émergence d'un effet de supraconductivité induite à l'échelle macroscopique. Le courant critique de la transition supraconductrice des films composites a pu être contrôlé par une tension de grille avec une sensibilité de cent nanoampères par volt. Le comportement sous champ magnétique transverse des films composites est similaire à celui des supraconducteurs comportant des joints de grains et est caractérisé, en particulier sous faible champ magnétique, par une forte sensibilité de la transition supraconductrice. Une étude approfondie a enfin montré que le matériau hybride G/Sn est un système percolant bidimensionnel qui se comporte, à l'approche de la transition supraconductrice, comme une jonction unique de taille micrométrique.Dans le cadre du second projet, des cavités supraconductrices radiofréquences (RF) ont été développées. Des pistes G/Sn ont été intégrées à ces circuits supraconducteurs dans l'optique de créer des résonateurs dont la fréquence de résonance est contrôlable par une tension de grille. Un procédé d'intégration de pistes G/Sn conjointement à plusieurs cavités à partir d'un seul transfert (pleine plaque) de graphène a été mis au point. Des mesures en transmission dans des conditions cryogéniques ont été effectuées pour caractériser ces dispositifs hybrides et étudier leur comportement dans le domaine RF
Superconducting proximity effect in macroscopic CVD-grown graphene decorated by tin nanoparticles is the central topic of this thesis. In this manuscript, two experimental projects are presented.The first of these projects consisted in developing and studying a new easy to handle and flexible material in which superconducting correlations extend over macroscopic scales. This material is a composite film made from the stacking of three original components: a few micrometers thin plastic film in parylene, a several centimeters squares layer of graphene, and a cluster of nanoparticles achieved by natural dewetting of tin on the graphene surface.Cryogenic transport measurements highlighted an induced superconductivity on the scale of the studied composite films pieces dimensions, of the order of the centimetre square. The superconducting critical current of the composite films showed gate tunability of about one hundred nanoamperes by volt. The behaviour of the composite films under a transverse magnetic field is similar to the one of granular superconductors and is characterised, especially under weak transverse magnetic field, by a high sensitivity of the superconducting transition. An in-depth study showed that the G/Sn hybrid material is a bidimensional percolating system that, when approaching the superconducting transition, behaves like a single mesoscopic Josephson junction.Within the framework of the second project, superconducting radiofrequency (RF) cavities have been developed. G/Sn patches have been integrated into these superconducting circuits in order to build gate tunable resonators. A process allowing to integrate G/Sn patches jointly to a series of several cavities from a single graphene transfer have been developed. Transmission measurements in cryogenic conditions have been performed to characterise these hybrid devices and to study their radiofrequency response

Disertační práce je zaměřena na metody a systémy pro měření vzdálenosti a lokalizaci RFID tagů pracujících v pásmu UHF. Úvod je věnován popisu současného stavu vědeckého poznání v oblasti RFID prostorové identifikace a stručnému shrnutí problematiky modelování a návrhu prototypů těchto systémů. Po specifikaci cílů disertace pokračuje práce popisem teorie modelování degenerovaného kanálu pro RFID komunikaci. Detailně jsou rozebrány metody měření vzdálenosti a odhadu směru příchodu signálu založené na zpracování fázové informace. Pro účely lokalizace je navrženo několik scénářů rozmístění antén. Modely degenerovaného kanálu jsou simulovány v systému MATLAB. Významná část této práce je věnována konceptu softwarově definovaného rádia (SDR) a specifikům jeho adaptace na UHF RFID, která využití běžných SDR systémů značně omezují. Diskutována je zejména problematika průniku nosné vysílače do přijímací cesty a požadavky na signál lokálního oscilátoru používaný pro směšování. Prezentovány jsou tři vyvinuté prototypy: experimentální dotazovač EXIN-1, měřicí systém založený na platformě Ettus USRP a anténní přepínací matice pro emulaci SIMO systému. Závěrečná část je zaměřena na testování a zhodnocení popisovaných lokalizačních technik, založených na měření komplexní přenosové funkce RFID kanálu. Popisuje úzkopásmové/širokopásmové měření vzdálenosti a metody odhadu směru signálu. Oba navržené scénáře rozmístění antén jsou v závěru ověřeny lokalizačním měřením v reálných podmínkách.

Cette thèse porte sur la caractérisation non destructive de structures 2D magnéto-diélectriques inhomogènes complexes. L’ensemble des étapes allant de l’expérience au traitement du problème inverse est traité. Dans un premier temps, un modèle direct reliant le champ diffusé aux propriétés électromagnétiques du matériau a été mis en place. Ce modèle requiert des calculs par éléments finis de la propagation de l’onde électromagnétique, en présence de l’objet observé lorsque celui-ci est positionné sur un support métallique. Une validation expérimentale a été réalisée via la mise en place d'un banc de mesure multi statique. Différentes étapes d'ajustements et d'étalonnages ont permis la réduction du bruit de mesure ainsi que des biais. L’inversion est traitée principalement par une approche linéaire, avec un choix attentif de la valeur des hyper paramètres qui y sont associés. Une fois les outils mis en place, six études ont été réalisées pour la validation de notre système d’imagerie 2D des propriétés électromagnétiques de matériaux magnéto-diélectriques inhomogènes. Cela comprend l’évaluation des incertitudes de mesure, de la résolution spatiale, la mesure de différents matériaux magnétiques et l’utilisation de différents supports à géométries variées. L’ensemble des résultats expérimentaux réalisés se place dans une hypothèse de géométrie 2D. C’est pourquoi, nous avons ensuite orienté nos travaux vers la recherche d’un design innovant permettant de faire évoluer le banc de mesure en un dispositif d’imagerie 3D. Dans cette perspective, une source secondaire vient se déplacer proche de la cible pour acquérir de l’information selon la troisième dimension
The subject of this thesis is the non-destructive characterization of complex inhomogeneous magneto-dielectric structures. Successively, the experimental developments, the modelling and the data treatments stages are addressed. A forward model that links the scattered field to the electromagnetic properties is established. This model requires some finite element computations in order to estimate the propagation of the electromagnetic wave in presence of the magneto-dielectric object which is glued on a metallic support. A multistatic bench has been designed and constructed in order to collect measured scattered fields. Several adjustments and calibration procedures have been carried out to reduce the measurement noise and biases. Next, the inverse problem has been dealt with, in order to retrieve the electromagnetic properties of the samples, from the measured scattered field. The inverse problem is mainly solved with a linear approach, with a careful selection of the hyperparameters. Once the system has been fine tuned, six studies have been realized to validate our 2D imaging system. The assessment of the measurement uncertainty, the evaluation of the spatial resolution, the characterization of various magnetics materials and the use of different supports with variable geometries have been performed. So far, all the developments were done under a 2D hypothesis. That is why, we have then focused our research on the design of a 3D innovative imaging setup. To this end, a secondary source moving close to the target has been added in order to gain information in the third direction. A numerical study has been performed to assess the expected performances of this new setup

Avec l'ouverture de la bande 57-66 GHz en Europe, de nouvelles technologies de communication sans fil à haut débit sont en cours de développement. De nombreux avantages liés à cette bande de fréquence ont notamment conduit à envisager la transposition du principe de l'identification par radiofréquence (RFID) en bande millimétrique : la MMID. Les réglementations internationales font notamment apparaître une bande passante commune de 5 GHz qui permettrait la mise en place de solutions universelles. De plus la sécurisation des communications point-à-point et la directivité des réseaux d'antennes offrent des perspectives intéressantes.Les travaux présentés dans cette thèse visent à contribuer au développement de la MMID. Ils soulignent les principaux verrous de cette technologie et présentent les différentes solutions proposées qui couvrent de multiples aspects : conception d'antennes et de réseaux d'antennes, conception de prototypes de tags MMID passifs, caractérisation et méthodologie de mesure dont la conception intégrale d'un banc de mesure en bande V, amélioration des performances des tags, et étude de fonctionnalités de capteur intégrées aux tags. Les différents prototypes de tags MMID fabriqués ont permis de réaliser des communications passives de type rétro-modulation jusqu'à 20 cm. De plus, des fonctions de capteur d'humidité et capteur de pression intégrées aux tags MMID ont été montrées expérimentalement. L'ensemble de ces résultats ouvre la voie à de nouvelles perspectives pour les domaines des télécommunications et des réseaux de capteurs en bande millimétrique
With the opening of the 57-66 GHz band in Europe, new high data-rate wireless communication technologies are currently under development. Numerous advantages linked to the frequency band conducted to consider the transposition of the radiofrequency identificaion (RFID) principle to the millimeter frequency band: the MMID. The international regulations provide a common bandwidth of 5 GHz allowing universal solutions. Moreover, the communication security of point-to-point networks and the directivities of the antennas present interesting perspectives.The presented work in this thesis looks for contributing to the development of MMID. The work underlines the principal locks of this technology and it presents the different proposed solutions covering multiple aspects: conception of antennas and antennas arrays, conception of MMID tags prototypes, characterization and measurement methodology including the complete conception of a measurement bench in V-band, improvement of the tags performances and study of sensing functionalities integrated in the tags. Different prototypes of MMID tags are fabricated and passive communications based on the backscattering of the tags were demonstrated up to 20 cm. In addition, humidity and pressure sensing functionalities were proved by experimentations. The overall of these results pave the way for new perspectives for the wireless communication domain and sensors networks in the millimeter-wave band

No
A loop feed meander-line Antenna (LFMLA) RFID tag on a relatively low dielectric constant substrate operates on the European UHF band 865-868 MHz is presented. The tag modeling is analyzed using two different electromagnetic simulator HFSS and CST. A prototype tag antenna is constructed and measured for validation. The input impedance of the proposed antenna is verified against the simulated data results, the measured and simulated results are found to be in good agreement. The compact size tag antenna shows excellent impedance matching to the typical input impedance of a RFID integrated circuit chip and a significant improvement in reading range up to 5 meters.

Τις τελευταίες δεκαετίες, οι διεργασίες πλάσματος με τάση διέγερσης ραδιοσυχνότητας χρησιμοποιούνται ολοένα και περισσότερο και απαντώνται σε διάφορες εφαρμογές όπως στην εναπόθεση υλικών, στην επεξεργασία επιφανειών κα. Αυτό έχει ως αποτέλεσμα οι εκκενώσεις αίγλης ραδιοσυχνότητας να προσελκύσουν έντονο επιστημονικό ενδιαφέρον. Μπορεί τα τελευταία χρόνια να έχει σημειωθεί σημαντική πρόοδος στον τομέα αυτό ωστόσο υπάρχει ακόμα και σήμερα ενδιαφέρον που αφορά το σχεδιασμό των συστημάτων αυτών καθώς και την ανάπτυξη μεθόδων που αφορούν την επαναληψιμότητα των διεργασιών καθώς και τον έλεγχο των ιδιοτήτων του πλάσματος. Ένας από αυτούς τους τομείς είναι ο ηλεκτρικός χαρακτηρισμός ηλεκτροδίων ραδιοσυχνότητας πηγών πλάσματος και η εύρεση της κατανεμημένης εμπέδησής τους και ακολούθως ο υπολογισμός της καταναλισκόμενης ισχύος σε εκκενώσεις αίγλης. Αυτές οι τεχνικές μπορούν να μας προσφέρουν σημαντικές πληροφορίες για τους μηχανισμούς και τα φαινόμενα που λαμβάνουν χώρα σε εκκενώσεις ραδιοσυχνότητας, οι οποίες αν στη συνεχεία αξιοποιηθούν να μας οδηγήσουν στον ακριβή προσδιορισμό και έλεγχο των συνθηκών. Στην εργασία αυτή αναλύονται μέθοδοι από τις οποίες προκύπτουν αποτελέσματα που αφορούν παραμέτρους του πλάσματος μέσω μετρήσεων τάσης, ρεύματος και διαφοράς φάσης σε κάποιο σημείο εξωτερικά του αντιδραστήρα. Παρουσιάζονται τα αποτελέσματα ηλεκτρικών μετρήσεων σε εκκενώσεις αργού που πραγματοποιήθηκαν σε μια χωρητικά συζευγμένη πηγή πλάσματος. Αρχικά παρουσιάζεται ο ηλεκτρικός χαρακτηρισμός της πηγής και αναλύονται τρεις μέθοδοι για τη μέτρηση και τον υπολογισμό της καταναλισκόμενης ισχύος της εκκένωσης. Στην πρώτη μέθοδο οι ηλεκτρικές μετρήσεις χρησιμοποιούνται για το προσδιορισμό ενός ισοδύναμου ηλεκτρικού κυκλώματος με κατανεμημένα στοιχεία (πυκνωτές, πηνία αντιστάσεις) το οποίο μπορεί να περιγράψει την εμπέδηση ανάμεσα στο σημείο μέτρησης εξωτερικά του αντιδραστήρα και την επιφάνεια του ηλεκτροδίου ραδιοσυχνότητας. Το ισοδύναμο αυτό κύκλωμα επιλύεται με βάση τους κανόνες του Kirchhoff και προκύπτουν οι τιμές της μιγαδικής τάσης και ρεύματος της εκκένωσης. Στη δεύτερη μέθοδο, η τάση καθώς και το ρεύμα της εκκένωσης υπολογίζονται μέσω ενός πίνακα ABCD, τα στοιχεία του οποίου έχουν υπολογιστεί από μετρήσεις σε ανοικτό και βραχυκυκλωμένο κύκλωμα. Η τρίτη μέθοδος, μοιάζει αρκετά με τη δεύτερη μόνο που έχει το πλεονέκτημα να είναι πιο απλή λόγω του ότι δεν απαιτεί τη μέτρηση της φάσης της εμπέδησης (της φάσης της τάσης σε σχέση με την τάση του ρεύματος).
Over the last decades, plasma processing has been widely used in various applications such as the deposition of thin films, surface modification, dry etching etc. As a result, radio-frequency discharges have attracted particular scientific interest. Despite the steps forward, there are still open issues especially concerning the design of plasma systems and the effective control of plasma parameters. A part of these issues is related to the electrical characterization of the stray impedance of the plasma electrode and the subsequent measurement and calculation of the real power consumption during the process. These techniques can lead to better understanding of the plasma processes and can also lead to more stable, reliable and almost ideal performing plasma systems. The aim of this study is to point out externally measured non-intrusive plasma parameters that could ease design, control and transferability of plasma conditions. In this work we demonstrate results of electrical characteristics of argon discharges carried out in a high vacuum capacitively coupled parallel plate reactor. Initially, the electrical characterization of the plasma reactor is presented and three methods for measuring and calculating the real power consumed in the discharge are analyzed.. At the first method, the electrical measurements are used to determine a simple equivalent circuit that can describe the parasitic impedances that interfere between the point of measurement and the RF electrode’s surface. The equivalent circuit model is then solved through Kirchhoff’s laws and values of the complex electrode’s voltage and current are obtained from the measured voltage and current at some point located outside the reactor. At the second method, the reactor is treated as a two-port network. The electrode’s voltage and current are calculated through the ABCD matrix of the reactor whose values a, b, c, d are extracted from open and short circuit measurements. The third method is a simplification of the second method as it does not require the phase of the impedance (the phase of the voltage relative to the current) for the calculations.