Ultra high frequency (UHF) radio frequency identification (RFID) systems suffer from issues that limit their widespread deployment and limit the number of applications where they can be used. These limitations are: lack of a well defined read zone, interference, and environment sensitivity. To overcome these limitations a novel receiver device is introduced into the system. The use of such device or devices mitigates the issues by enabling more "anchor points" in the system. Two such devices exist in industry and academia: the Astraion Sensatag and the Gen2 Listener. The drawbacks of the Sensatag is that it offers poor performance in capturing tag signals. The Gen2 Listener is based on the expensive software defined radio hardware. The purpose of the thesis was to develop a receiver that will enable several new RFID applications that are not available with current RFID systems. The receiver, named ARR (Augmented RFID Receiver), receives tag and reader signals, which are decoded by an FPGA and the results are reported through Ethernet. This device is central to the augmented RFID system. To show the suitability of such an approach, the performance of the implementation was compared to the other two outlined solutions. A comparison of the read rate and range of the implementations were the defining factors. The analysis showed that the ARR is capable of receiving tag signals with a read rate of 50% for passive and 66% for semi-passive tags at a one meter distance and is capable of receiving tag signals at a maximum of 3.25 meters for passive and 5.5 meters for semi- passive tags, with the reader being within 8 meters of the ARR. Two applications were implemented to showcase the ARR: an RFID portal and protocol analyzer.

Indoor localization with proximity information in ultra-high-frequency (UHF) radio-frequency-identification (RFID) is widely considered as a potential candidate of locating items in Internet-of-Things (IoT) paradigm. First, the proximity-based methods are less affected by multi-path distortion and dynamic changes of the indoor environment compared to the traditional range-based localization methods. The objective of this dissertation is to use tag-to-tag backscattering communication link in augmented UHF RFID system (AURIS) for proximity-based indoor localization solution. Tag-to-tag backscattering communication in AURIS has an obvious advantage over the conventional reader-to-tag link for proximity-based indoor localization by keeping both landmark and mobile tags simple and inexpensive. This work is the very first thesis evaluating proximity-based localization solution using tag-to-tag backscattering communication.Our research makes the contributions in terms of phase cancellation effect, the improved mathematical models and localization algorithm. First, we investigate the phase cancellation effect in the tag-to-tag backscattering communication, which has a significant effect on proximity-based localization. We then present a solution to counter such destructive effect by exploiting the spatial diversity of dual antennas. Second, a novel and realistic detection probability model of ST-to-tag detection is proposed. In AURIS, a large set of passive tags are placed at known locations as landmarks, and STs are attached mobile targets of interest. We identify two technical roadblocks of AURIS and existing localization algorithms as false synchronous detection assumption and state evolution model constraints. With the new and more realistic detection probability model we explore the use of particle filtering methodology for localizing ST, which overcomes the aforementioned roadblocks. Last, we propose a landmark-based sequential localization and mapping framework (SQLAM) for AURIS to locate STs and passive tags with unknown locations, which leverages a set of passive landmark tags to localize ST, and sequentially constructs a geographical map of passive tags with unknown locations while ST is moving in the environment. Mapping passive tags with unknown locations accurately leads to practical advantages. First, the localization capability of AURIS is not confined to the objects carrying STs. Second, the problem of failed landmark tags is addressed by including passive tags with resolved locations into landmark set. Each of the contributions is supported by extensive computer simulation to demonstrate the performance of enhancements.

This master thesis deals with the problem of the origin and expression of partial discharges in dielectric materials. In the thesis the theoretical foundations, types and parameters of partial discharges are described. In particular, it deals with UHF (ultra high freqeuncy) electromagnetic radiation using UHF method of partial discharge detection. It also deals with the partial discharge UHF signal simulation. The development of UHF sensor systems for partial discharges requires a dive that can simulate them as accurately as possible. Furthermore, a workplace was designed for simulation and detection of partial discharges and processing of their time and frequency characteristics.

This thesis deals with RFID tags design. It comprises an overview of the RDIF technology while focusing upon the passive tags in UHF band. The CST Microwave studio software has been used for draft simulations. The resulting tags have been subjected to parameter measuring – the reflection coefficient, the minimum capacity needed to switch on the tag, the maximum reading distance. The influence of the proximity of metal objects and other materials has also been examined.

No description available.

No / Abstract: Radio Frequency Identification (RFID) systems has gained increasing popularity with multiple deployments to existing wireless sensors in a view to achieve energy and overall operational efficiency at a much lower cost. This paper presents the design and analysis of a UHF (860-868MHZ) passive tag using HFSS (High Frequency Structural Simulator) platform. It explores specific tag geometry characteristics that affect overall tag antenna performance and presents the optimised result. The simulation results and parametric analysis are compared. Further simulations on HFSS platform is carried out to theoretically demonstrate the reflections of the tag when deployed as sensors to multiple levels of a cistern.

Les étiquettes d'identification radiofréquence passifs (RFID) sont des systèmes télé-communiquant dont l'approvisionnement en énergie se fait via les ondes électromagnétiques. De plus en plus présents dans notre environnement (passeport, badge d'accès, gestion de stock), ils ont l'avantage d'avoir une durée de vie presque infinie, et ne consomment de l'énergie que lorsqu'ils sont sollicités. Par ailleurs, leur moyen de communiquer, sans fil, permet de les utiliser dans des endroits difficiles d'accès pour des lecteurs optiques type code à barre. Toutefois, la portée de tels systèmes est limitée par l'efficacité de la récupération de l'énergie provenant des ondes. Dans ce cadre, l'augmentation de la portée des étiquettes RFID, notamment pour les applications de logistique est un élément primordial.Sont présentés dans cette thèse différents moyens d'augmenter cette portée notamment grâce à l'amélioration des blocs de récupération d'énergie ou l'adaptation d'impédance, tout en respectant des contraintes liées au coût du système. La première partie se focalise sur la réduction des pertes du bloc de récupération d'énergie par l'optimisation du layout. Une architecture à haut rendement à transistor polarisé est ensuite proposée. Pour finir, l'impact de la rétro-modulation et de l'adaptation d'impédance en fréquence sur la récupération d'énergie sont étudiés et améliorés. / The passive radio frequency identification tags (RFID) systems communicate with a remote power supply thanks to electromagnetic waves. Increasingly present in our environment (biometric passport, inventory management), they present the advantage to have an almost infinite lifetime, and consume energy only when they are solicited. Moreover, because it is a wireless way to communicate, it is possible to use these systems places inaccessible to optical drives type bar code. However, the range of such systems is limited by the efficiency of the recovery of energy from waves. In this context, increasing the range of RFID tags, especially for logistics applications is essential.In this these, different ways to increase the range are studied. The first part focuses on the reduction of losses on the rectifying circuitry thanks to layout optimization. An high performances architecture with transistor biased is then proposed. Finally, the impact of backscattering and impedance matching on the energy recovery are studied and improved.

[pt] Com o advento da TV digital no Brasil, a necessidade de reuso dos canais para diferentes entidades, e a importância das emissoras oferecerem a melhor qualidade de serviço para seus usuários, dentre outros fatores, criam um ambiente propício para o estudo de modelos de predição de cobertura para que tanto as emissoras possam dimensionar corretamente suas estações, como os órgãos reguladores possam distribuir os canais de forma harmoniosa. Este trabalho apresenta medidas de campo realizadas nas cidades do Rio de Janeiro, Belo Horizonte e São Paulo e as compara com valores calculados usando os modelos de Deygout-Assis, CRC-Predict, ITU-R P.526 e ITU-R P.1546. / [en] Since the beginning of Digital TV in Brazil, the need of channel reuse for different broadcasters, the importance to offer a service with good quality, among other issues, created a good environment for studying prediction methods for RF coverage, so that broadcasters can correctly specify its stations and also the government regulators can allocate channels without interference. This work presents field measurements made in Rio de Janeiro, Belo Horizonte and São Paulo and compare them with predicted values using the methods of Deygout- Assis, CRC-Predict, ITU-R P.526 e ITU-R P.1546.

[pt] Esta tese tem como objetivo a caracterização experimental do canal de propagação na faixa de UHF para as aplicações em sistemas de TV Digital. Através de campanhas de medições de campo em condições que aproximam a operação real destes sistemas foi levantado um conjunto de dados que permitiu: a avaliação de métodos de previsão da perda média de propagação em regiões urbanas densas; a determinação do retardo médio e banda de coerência do canal nestas regiões, em condições de recepção externa e interna; a caracterização estatística do espalhamento de retardos do canal; e a simulação do canal em diferentes condições de recepção para obtenção de seu perfil de retardos. São apresentadas as três campanhas de medidas realizadas, incluindo a descrição das regiões e configurações de medição, técnicas de medição e processamento de dados utilizados. A seguir é apresentada uma análise da perda média de propagação nas medições realizadas e a comparação com as previsões fornecidas para os mesmos percursos pela implementação do modelo do ITU-R. A caracterização em banda larga do canal é realizada pela modelagem estatística do perfil de retardos de multipercurso do canal. Finalmente, são apresentados os resultados de simulações para obtenção do perfil de retardos do canal com base nos resultados experimentais obtidos e a modelagem estatística desenvolvida nesta tese. / [en] This thesis aims the experimental characterization of propagation channel of UHF band for applications in Digital TV systems. Through of measurements in the field conditions as close to actual operation of these systems was raised a set of data that allowed: the evaluation of methods for prediction of propagation mean loss in dense urban areas, determining the mean power delay and the coherence bandwidth of the channel in these regions, in two types of reception conditions, indoor and outdoor, the statistical characterization of the delay spread, and the simulation of channel for different conditions for obtain a power delay profile. Three measures campaigns are reported, including the description of regions and setup of measurement; measurement techniques and data processing methodology. It is presented a review of the average loss for the measurements developed and compared with data provided for same pathways, for the implementation of the ITU-R model. The characterization of the broadband channel is carried out by the statistical modeling of power delay profile of channel. Finally, it is presents the simulation´s results of power delay based on experimental results and statistical modeling developed in this thesis.

Les dimensions d’une antenne sont inversement proportionnelles à leurs fréquences de fonctionnement. De plus, la miniaturisation d’une antenne entraîne la dégradation de ses performances électriques et de rayonnement. Par conséquent, il est important pour le concepteur de trouver un bon compromis entre le taux de miniaturisation et les performances souhaitées. L’objet de cette thèse est de proposer une antenne miniature possédant les meilleures caractéristiques possibles dans la bande UHF de la RFID (860MHz – 960MHz), facile à réaliser et à moindre coût d’industrialisation. Les travaux de cette thèse ont montré qu’un couplage magnétique d’une cellule de métamatériaux avec une demi-boucle permet d’obtenir des structures antennaires intéressantes de par leurs dimensions de l’ordre de λ0/10, leur efficacité et leur fonctionnement en multibande. Différentes techniques sont appliquées pour améliorer les performances des antennes développées à savoir le gain, la directivité et la polarisation circulaire et/ou elliptique. / Antenna dimensions are inversely proportional to their operating frequencies. Besides, the antenna miniaturization degrades its electrical and radiation performances. Therefore it is important for the antenna designer to find a good compromise between the miniaturization rate and the desired performances. The purpose of this thesis is to obtain a miniature antenna which has good characteristics in the UHF band of RFID (860MHz - 960MHz), easy to implement and with low industrialization cost. The works described in this thesis showed that a magnetic coupling of a metamaterial cell with a half loop provides interesting antennas in terms of dimensions of about λ0/10, efficiency and multiband behavior. Different techniques are applied to improve the performances of realized antennas as gain, directivity and circular and/or elliptical polarization.