76 research outputs found

    Magneto-inductive HF RFID system

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    Efforts to increase read range in passive HF RFID systems are hampered by the poor range scaling law of inductive coupling. An alternative approach to enlarging capture volume—increasing the lateral extent of the antenna—is proposed, using a magneto-inductive (MI) travelling wave arrangement to allow larger antenna sizes. A theory of load modulation in MI systems is first presented, together with field simulations in the capture volume. A 2.3 metre-long MI antenna is then constructed, and an active tag emulator is used to demonstrate load modulation. RFID is then demonstrated, with the antenna in both reflection and transmission modes, using a custom reader constructed from laboratory equipment. A transverse read range of 0.5 m is obtained using commercial off-the-shelf RFID cards with 12 W RF power, with high uniformity along the length of the antenna

    TechNews digests: Jan - Nov 2008

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    TechNews is a technology, news and analysis service aimed at anyone in the education sector keen to stay informed about technology developments, trends and issues. TechNews focuses on emerging technologies and other technology news. TechNews service : digests september 2004 till May 2010 Analysis pieces and News combined publish every 2 to 3 month

    Sensor-based management systems based on RFID technology

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    Παρατηρήσεις έκδοσης: λείπουν οι σελίδες 78, 102 από το φυσικό τεκμήριο.In this diploma thesis, the RFID technology is analyzed (operating principles, readers' and tags hardware, coding, modulation, anticollision procedures, frequencies, standards, applications). Moreover, a protocol to synchronize readers working in a multi-reader multi-tag environment is proposed. The protocol is applied to the store shelf scanning application and further refined to meet the requirements of this specific application

    Electronic identification systems for asset management

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    Electronic identification is an increasingly pervasive technology that permits rapid data recovery from low-power transponders whenever they are placed within the vicinity of an interrogator device. Fundamental benefits include proximity detection not requiring line-of-sight, multiple transponder access and data security. In this document, electronic identification methods for asset management are devised for the new target application of electrical appliance testing. In this application mains-powered apparatus are periodically subjected a prescribed series of electrical tests performed by a Portable Appliance Tester (PAT). The intention is to enhance the process of appliance identification and management, and to automate the test process as far as possible. Three principal methods of electronic identification were designed and analysed for this application: proximity Radio Frequency Identification (RFID), cable RFID and power- line signalling. Each method relies on an inductively coupled mechanism that utilities a signalling technique called direct-load modulation. This is particularly suited to low- cost passive transponder designs. Physical limitations to proximity RFID are identified including coil size, orientation and susceptibility to nearby conducting surfaces. A novel inductive signalling method called cable RFID is then described that permits automatic appliance identification. This method uses the appliance power cable and inlet filter to establish a communication channel between interrogator and transponder. Prior to commencing the test phase, an appliance is plugged into the PAT and identified automatically via cable RFID. An attempt is made to extend the scope of cable RFID by developing a novel mains power-line signalling method that uses direct-load modulation and passive transponders. Finally, two different implementations of RFID interrogator are described. The first takes the form of an embeddable module intended for incorporation into electronic identification products such as RFID enabled PAT units. Software Defined Radio (SDR) principles are applied to the second interrogator design in an effort to render the device reconfigurable

    Analysis of Wireless Body-Centric Medical Sensors for Remote Healthcare

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    Aquesta tesi aborda el problema de trobar solucions confortables, de baixa potència i sense fils per aplicacions mèdiques. La tesi tracta els avantatges i les limitacions de tres tecnologies de comunicació diferents per la mesura de paràmetres del cos i mètodes per redissenyar sensors per avaluacions òptimes centrades en el cos. La tecnologia RFID es considera una de les solucions més influents per superar el problema del consum d'energia limitat, a causa de la presència de molts sensors connectats. També s'ha estudiat la tecnologia Bluetooth de baixa energia per resoldre els problemes de seguretat i la distància de lectura que, en general, representen el coll d'ampolla de RFID pels sensors de cos. Els dispositius analògics poden reduir dràsticament les necessitats d'energia a causa dels sensors i les comunicacions, considerant pocs elements i un mètode de transmissió simple. S'estudia un mètode de comunicació completament passiu, basat en FSS, que permet una distància de lectura raonable amb capacitats de detecció precises i confiables, que s'ha discutit en aquesta tesi. L'objectiu d'aquesta tesi és investigar múltiples tecnologies sense fils per dispositius portàtils per identificar solucions adequades per aplicacions particulars en el camp mèdic. El primer objectiu és demostrar la facilitat d'ús de les tecnologies econòmiques sense bateria com un indicador útil de paràmetres fisiopatològics mitjançant la investigació de les propietats de les etiquetes RFID. A més a més, s'ha abordat un aspecte més complex respecte a l'ús de petits components passius com sensors sense fils per trastorns del son. Per últim, un altre objectiu de la tesi és el desenvolupament d'un sistema completament autònom que utilitzi tecnologia BLE per obtenir propietats avançades mantenint baix tant el consum com el preuEsta tesis aborda el problema de encontrar soluciones confortables, inalámbricas y de baja potencia para aplicaciones médicas. La tesis discute las ventajas y limitaciones de tres tecnologías de comunicación diferentes para la medición en el cuerpo y los métodos para elegir y remodelar los sensores para evaluaciones óptimas centradas en el cuerpo. La tecnología RFID se considera una de las soluciones más influyentes para superar el consumo de energía limitado debido a la presencia de muchos sensores conectados. Además, la baja energía de Bluetooth se ha estudiado se ha estudiado la tecnologia Bluetooth de baja energia para resolver los problemas de seguridad y la distancia de lectura que, en general, representan el cuello de botella de la RFID para los sensores de cuerpo. Los dispositivos analógicos pueden reducir drásticamente las necesidades de energía debido a los sensores y las comunicaciones, considerando pocos elementos y un método de transmisión simple. Se estudia un método de comunicación completamente pasivo, basado en FSS, que permite una distancia de lectura razonable con capacidades de detección precisas y confiables, que se ha discutido en esta tesis. El objetivo de esta tesis es investigar múltiples tecnologías inalámbricas para dispositivos portátiles para identificar soluciones adecuadas para aplicaciones particulares en campos médicos. El primer objetivo es demostrar la facilidad de uso de las tecnologías económicas sin batería como un indicador útil de dichos parámetros fisiopatológicos mediante la investigación de las propiedades de las etiquetas RFID. Además, se ha abordado un aspecto más complejo con respecto al uso de pequeños componentes pasivos como sensores inalámbricos para enfermedades del sueño. Por último, un resultado de la tesis es desarrollar un sistema completamente autónomo que utilice la tecnología BLE para obtener propiedades avanzadas que mantengan la baja potencia y un precio bajo.This thesis addresses the problem of comfortable, low powered and, wireless solutions for specific body-worn sensing. The thesis discusses advantages and limitations of three different communication technologies for on body measurement and investigate methods to reshape sensors for optimum body-centric assessments. The RFID technology is considered one of the most influential solutions to overcome the limitated power consumption due to the presence of many sensors connected. Further, the Bluetooth low energy has been studied to solve security problems and reading distance that overall represent the bottleneck of the RFID for the body-worn sensors. Analog devices can drastically reduce the energy needs due to the sensors and the communications, considering few elements and a simple transmitting method. An entirely passive communication method, based on FSS is studied, enabling a reasonable reading distance with precise and reliable sensing capabilities, which has been discussed in this thesis. The objective of this thesis is to investigate multiple wireless technologies for wearable devices to identify suitable solutions for particular applications in medical fields. The first objective is to demonstrate the usability of the inexpensive battery-less technologies as a useful indicator of such a physio-pathological parameters by investigating the properties of the RFID tags. Furthermore, a more complex aspect regards the use of small passive components as wireless sensors for sleep diseases has been addressed. Lastly, an outcome of the thesis is to develop an entirely autonomous system using the BLE technology to obtain advanced properties keeping low power and a low price

    Analyse et exploitation des non linéarités dans les systèmes RFID UHF passifs

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    Powered by the exploding popularity of the Internet-of-Things (IoT), the demand for tagged devices with labels capable to ensure a reliable communication with added functions beyond the identification, such as sensing, location, health-care, among others, is growing rapidly. Certainly this growing is headed by the well-established Radio Frequency Identification (RFID) technology, and the use of wireless low-cost self-powered tags, in other words passive RFID tags, is the most widespread used alternative. In the constant evolution on this field, usually new software treatments are offered at the application layer with the objective to processing data to produce some new information. Further works aimed at improving the physical layer around the tag antenna miniaturization and matching techniques. So far, little or no work had been done on the exploitation of the communication channel, and certainly none has been done on the exploitation of the non-linear behavior of RFID chips.After presenting the RFID technology and phenomena produced by Radio Frequency (RF) non-linear devices, and leaning in some nearby works on the field, the core of this thesis starts by exposing two characterization platforms for the evaluation of non-linear phenomena presented during the reader-tag communication. One is specialized in radiating measurements considering the whole tag (antenna and chip) under test. The other is specialized in conducted measurements directly over RFID chips, allowing performing different parametric studies (power dependency, impedance, harmonic production, sensitivity). The characterization results show that harmonic signals generated from the passive RFID chip carry information.By exploiting the characterization results and to verify the hypothesis of exploitation of non-linearities in RFID, i.e. the use of harmonic signals, the research is pursued by designing, fabricating, and measuring four different configurations of RFID tags. The new RFID tags operate at the fundamental frequency in the UHF band and at its 3^{rd} harmonic in the microwave band. Antenna design policies, fabrication details, and parametric studies on the performance of the new prototypes are presented. The parametric study takes special care in the antenna structure, kind of chip used, received power, and read range.Finally, some alternatives approaches for the exploitation of non-linear effects generated by rectifying devices are presented. Some theoretical aspects and experimental results are discussed linking the passive RFID technology to the theories of Wireless Power Transfer (WPT) and Electromagnetic Energy Harvesting (EEH). The solution takes advantage of the non-linear nature of rectifying elements in order to maximize the RF-to-DC conversion efficiency of EEH devices and increase the read range of passive RFID tags. The solution triggers on the design of a RF multi-device system. The design procedure and tests consider three non-linear phenomena: (1) the impedance power dependency, (2) the harmonic production, and (3) the rectifying dependence on the RF waveform.Avec l'explosion de l'Internet des Objets (IoT), de nouveaux dispositifs permettant de tagguer les objets sont nécessaires afin de permettre non seulement leur identification mais aussi d'assurer des communications fiables et de nouvelles fonctionnalités comme la détection, la localisation ou la capture d'informations. Cette tendance s'appuie sur la technologie bien établie qu'est la radiofréquence par identification (RFID) et donc l'utilisation d'étiquettes (ou tags) faibles coûts et télé-alimentés. Dans ce contexte, de nombreux travaux au niveau de la couche d'application se tournent vers la mise au point de traitements logiciels complémentaires visant à produire de nouveaux types d'information. D'autres travaux visent à améliorer la couche physique avec l'objectif de miniaturiser encore le tag mais aussi de le doter de nouvelles capacités. Jusqu'à présent, il n'existe quasiment pas de travaux concernant la transmission du signal et aucun sur l'exploitation du comportement non-linéaire des puces RFID. Cette thèse vise à étudier les phénomènes non-linéaires produits lors d'une communication RFID.Dans la première partie, deux plateformes de mesure et de caractérisation spécifiques ont été développées : la première vise à observer les signaux au cours d'une communication RFID, et alors caractériser et analyser les effets liés aux phénomènes non linéaires ; la seconde permet d'effectuer différentes mesures directement sur les puces et les caractériser en termes d'impédance, production d'harmoniques et sensibilité. Ces plateformes ont permis : 1) de mettre en évidence que les fréquences harmoniques sont porteuses d'informations qui peuvent être exploitées et même offrir de nouvelles fonctionnalités ; 2) d'obtenir de nombreuses informations sur les propriétés des puces et d'en établir un modèle électrique précis ; 3) de déterminer des critères permettant d'évaluer la performance des tags dans le contexte étudié.Dans la deuxième partie, plusieurs nouveaux tags RFID ont été conçus, fabriqués, mesurés et évalués. Ces nouveaux tags fonctionnent non seulement dans la bande UHF mais aussi sont adaptés à la troisième harmonique dans la bande des microondes. Une méthodologie et des lignes directives d'aide à la conception de ce type de tags ont été établies et s'appuient sur les deux plateformes développées afin de caractériser les différents éléments. Dans un même temps, les effets liés à la fabrication ont aussi été étudiés et des études paramétriques ont permis de mettre en évidence l'effet sur les performances de la géométrie de l'antenne et du type de puce utilisée.Dans une troisième partie, les études se sont focalisées à exploiter les effets non-linéaires des dispositifs de redressement. L'idée générale est de coupler la RFID passive avec les dispositifs de transferts de puissance et de récupération d'énergie avec pour objectifs 1) de maximiser l'efficacité de conversion RF – continu 2) et d'augmenter la distance de lecture des tags passifs. Plusieurs prototypes ont été réalisés et leurs performances ont été démontrées.L'ensemble de ces travaux a mis en évidence un nouveau concept de communication RFID exploitant les non-linéarités générées par les puces RFID. Ce concept ouvre la voie à de nouvelles applications. et a fait l'objet d'une demande de brevet international

    The design and use of a digital radio telemetry system for measuring internal combustion engine piston parameters.

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    During the course of this project, a digital radio telemetry system has been designed and shown to be capable of measuring parameters from the piston of an internal combustion engine, under load. The impetus for the work stems from the need to sample the appropriate data required for oil degradation analysis and the unavailability of system to perform such sampling. The prototype system was designed for installation within a small Norton Villiers C-30 industrial engine. This choice of engine presented significant design challenges due to the small size of the engine (components and construction) and the crankcase environment. These challenges were manifest in the choice of carrier frequency, antenna size and location, modulation scheme, data encoding scheme, signal attenuation, error checking and correction, choice of components, manufacturing techniques and physical mounting to reciprocating parts. In order to overcome these challenges detailed analysis of the radio frequency spectrum was undertaken in order to minimise attenuation from mechanisms such as, absorption, reflection, motion, spatial arrangement and noise. Another aspect of the project concerned the development of a flexible modus operandi in order to facilitate a number of sampling regimes. In order to achieve such flexibility a two-way communication protocol was implemented enabling the sampling system to be programmed into a particular mode of operation, while in use. Additionally the system was designed to accommodate the range of signals output from most transducer devices. The sampling capabilities of the prototype system were extended by enabling the system to support multiple transducers providing a mixture of output signals; for example both analogue and digital signals have been sampled. Additionally, a facility to sample data in response to triggering stimuli has been tested; specifically a sampling trigger may be derived from the motion of the piston via an accelerometer. Ancillary components, such as interface hardware and software, have been developed which are suitable for the recording of data accessed by the system. This work has demonstrated that multi-transducer, mixed signal monitoring of piston parameters, (such as temperature, acceleration etc.) using a two-way, programmable, digital radio frequency telemetry system is not only possible but provides a means for more advanced instrumentation

    Wireless colorimetric readout to enable resource-limited point-of-care

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    Patientennahe Diagnostik in Entwicklungsländer birgt spezielle Herausforderungen, die ihren Erfolg bisher begrenzen. Diese Arbeit widmet sich daher der Entwicklung eines in seiner Herstellung skalierbaren und vielseitig einsetzbaren funkbasierten Auslesegerätes für Laborteststreifen. Durch die Kombination einer wachsenden Auswahl an papierbasierten Teststreifendiagnostiken mit gedruckter Elektronik und unter Berücksichtigung des diagnostischen Alltags im südlichen Afrika wurde ein Gerät entwickelt, das Teststreifen zuverlässig ausliest und die Daten per Funk an eine Datenbank übertragen kann. Die Technik basiert auf RFID-Tags (radio frequency identification devices), welche auf verschiedene flexible Substrate gedruckt wurden, um die technische Umsetzbarkeit und Funktionalität zu evaluieren. Um den Preis für die geplante Anwendung niedrig zu halten, wurden unter anderem Papier und Karton als Substrate genutzt. Das Ergebnis dieser Studie sind passive RFID-Tags auf unterschiedlichen, meist günstigen Substraten, die über eine Distanz von über 75 mm betrieben und ausgelesen werden können. Basierend auf der über RFID bereitgestellten Energie und Datenübertragung wurde eine Ausleseeinheit für Standardpapierstreifentests entwickelt und integriert. Durch das Auslesen verschiedener Teststreifen wurde das Gerät evaluiert und in seiner Aussagekraft mit einer scanner-basierten Aufnahme und anschließender Bildanalyse (ImageJ), einem kommerziellen Auslesegerät sowie einer manuellen Auslesung mit Hilfe von Farbtabellen verglichen. Das Gerät kann die Streifen zuverlässig auslesen und die Daten über die RFID-Schnittstelle übertragen. Die funkbasierte Ausleseeinheit ist mit verschiedenen kommerziellen Teststreifen sowohl im biodiagnostischen (lateral flow tests) wie auch im chemischen Bereich (pH-Wert) kompatibel. Die modulare Lösung erlaubt ein breites Einsatzgebiet und führt dadurch zu reduzierten Trainingszeiten der Anwender und einer zuverlässigen Handhabung. Die vorgestellte Lösung ist äußerst kostengünstig und bedarf keiner Wartung, wodurch sie sich sehr gut für den Einsatz in abgelegenen Feldkrankenhäusern eignet. Es wurde ein skalierbarer Prototyp entwickelt, der auf konventionellen Herstellungsverfahren der Verpackungsindustrie aufbaut. Aktuell handelt es sich noch um einen bogenbasierten Prozess, der sich aber prinzipiell auch auf Rolle-zu-Rolle Maschinen übertragen lässt. Bei der Entwicklung des Geräts spielte die Möglichkeit der lokalen Herstellung in den Einsatzländern eine große Rolle. Diese hätte neben der Generierung von Arbeitsplätzen auch den Vorteil einer einfacheren Verteilung der Geräte in ländliche Regionen, in denen sie den größten Nutzen für die Diagnostik erzielen würden
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