Orientador: Leonardo Lorenzo Bravo Roger / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Tecnologia / Made available in DSpace on 2018-08-26T21:14:03Z (GMT). No. of bitstreams: 1 SantosSouza_GilbertodeTadeu_M.pdf: 4051949 bytes, checksum: 3271a81290629f1d51c661d022a0cbd7 (MD5) Previous issue date: 2015 / Resumo: O projeto e a análise teórico-experimental de uma nova etiqueta sem chip para RFID com comunicação redundante é apresentado. Esta nova etiqueta poderá ser capaz de operar em duas bandas de frequências diferentes para a transmissão da informação binária, aproveitando a utilização em sua concepção de antenas dual-band. A técnica aqui mencionada é clássica, conhecida como diversidade de frequência, mas é utilizada neste trabalho pela primeira vez aplicada em etiquetas chipless de RFID visando aumentar a confiabilidade da comunicação com as leitoras de RFID. Simulações realizadas do novo dispositivo proposto com o software HFSS (High Frequency Structural Simulator) mostraram o seu desempenho adequado. A metodologia do projeto é apresentada passo a passo e os resultados são analisados e discutidos no texto / Abstract: The project and the theoretical-experimental analysis of a new chipless RFID tag with redundant communication is presented. This new tag may be capable to operate in two different frequencies bands for the transmission of binary information, taking advantage of the use in its design of dual-band antennas. The technique mentioned here is classic, known as frequency diversity, but it is used in this work for the first time applied in chipless RFID tags to increase the reliability of the communication with the RFID readers. Simulations of the proposed new device with HFSS (High Frequency Structural Simulator) software showed an adequate performance. The project methodology is presented step by step and the results are analyzed and discussed in the text / Mestrado / Tecnologia e Inovação / Mestre em Tecnologia

An ID generating circuit is unquestionably the core of a chipless RFID tag. For convenience of printing process and cost consideration, the circuit should be kept as simple as possible. Based on the cognition, an 8-bit time-domain based ID generating circuit that merely consists of a ML and eight capacitors was offered, and implemented on photo-paper substrates via inkjet printing process. In addition to the experimental measurements, the circuit was also input into circuit simulators for cross-validation. The good agreement between simulations and measurements is observed, exhibiting the tag technical feasibility. Besides of low cost, the tag has wide compatibility with current licensed RFID spectrum, which will facilitate the future deployment in real applications. Compared   to  time-domain   based  chipless   tags,  frequency   signatures   based chipless RFID tags are expected to offer a larger coding capacity. As a response, we presented a 10-bit frequency-domain based chipless RFID tag. The tag composed of ten configurable LC resonators was implemented on flexible polyimide substrate by using  fast  toner-transferring  process.  Field  measurements  revealed  not  only  the practicability  of  the  tag,  but  also  the  high  signal  to  noise  ratio  (SNR).  Another frequency domain tag consists of a configurable coplanar LC resonator. With the use of all printing process, the tag was for the first time realized on common packaging papers.  The tag feasibility was confirmed by subsequent measurements. Owing to the ultra-low cost potential and large SNR, The tag may find wide applications in typical RFID solutions such as management of paper tickets for social events and governing of smart documents. Ultra wide band (UWB) technology possesses a number of inherent merits such as high speed communication and large capacity, multi-path immunity, accurate ranging and positioning, penetration through obstacles, as well as extremely low-cost and low- power transmitters. Thus, passive UWB RFIDs are expected to play an important pole in  the future identification applications for IoT. We explained the feature difference between  UWB  chipless  tags  and  chip  based  tags,  and  forecasted  the  applications respectively  based on the comparison  between the two technologies.  It is expected that the two technologies will coexist and compensate each other in the applications of IoT. Lastly, the thesis ends up with brief summary of the author’s contributions, and technical prospect for the future development of printable chipless RFID tags. / <p>QC 20140304</p>

Radio frequency identification (RFID) and sensing are two key technologies enabling the Internet of Things (IoT). Development of RFID tags augmented with sensing capabilities (RFID sensor tags) would allow a variety of new applications, leading to a new paradigm of the IoT. Chipless RFID sensor technology offers a low-cost solution by eliminating the need of an integrated circuit (IC) chip, and is hence highly desired for many applications. On the other hand, printing technologies have revolutionized the world of electronics, enabling cost-effective manufacturing of large-area and flexible electronics. By means of printing technologies, chipless RFID sensor tags could be made flexible and lightweight at a very low cost, lending themselves to the realization of ubiquitous intelligence in the IoT era. This thesis investigated three construction methods of printable chipless RFID humidity sensor tags, with focus on the incorporation of the sensing function. In the first method, wireless sensing based on backscatter modulation was separately realized by loading an antenna with a humidity-sensing resistor. An RFID sensor tag could then be constructed by combining the wireless sensor with a chipless RFID tag. In the second method, a chipless RFID sensor tag was built up by introducing a delay line between the antenna and the resistor. Based on time-domain reflectometry (TDR), the tag encoded ID in the delay time between its structural-mode and antenna-mode scattering pulse, and performed the sensing function by modulating the amplitude of the antenna-mode pulse. In both of the above methods, a resistive-type humidity-sensing material was required. Multi-walled carbon nanotubes (MWCNTs) presented themselves as promising candidate due to their outstanding electrical, structural and mechanical properties. MWCNTs functionalized (f-MWCNTs) by acid treatment demonstrated high sensitivity and fast response to relative humidity (RH), owing to the presence of carboxylic acid groups. The f-MWCNTs also exhibited superior mechanical flexibility, as their resistance and sensitivity remained almost stable under either tensile or compressive stress. Moreover, an inkjet printing process was developed for the f-MWCNTs starting from ink formulation to device fabrication. By applying the f-MWCNTs, a flexible humidity sensor based on backscatter modulation was thereby presented. The operating frequency range of the sensor was significantly enhanced by adjusting the parasitic capacitance in the f-MWCNTs resistor. A fully-printed time-coded chipless RFID humidity sensor tag was also demonstrated. In addition, a multi-parameter sensor based on TDR was proposed.The sensor concept was verified by theoretical analysis and circuit simulation. In the third method, frequency-spectrum signature was utilized considering its advantages such as coding capacity, miniaturization, and immunity to noise. As signal collision problem is inherently challenging in chipless RFID sensor systems, short-range identification and sensing applications are believed to embody the core values of the chipless RFID sensor technology. Therefore a chipless RFID humidity sensor tag based on near-field inductive coupling was proposed. The tag was composed of two planar inductor-capacitor (LC) resonators, one for identification, and the other one for sensing. Moreover, paper was proposed to serve as humidity-sensing substrate for the sensor resonator on accounts of its porous and absorptive features. Both inkjet paper and ordinary packaging paper were studied. A commercial UV-coated packaging paper was proven to be a viable and more robust alternative to expensive inkjet paper as substrate for inkjet-printed metal conductors. The LC resonators printed on paper substrates showed excellent sensitivity and reasonable response time to humidity in terms of resonant frequency. Particularly, the resonator printed on the UV-coated packaging paper exhibited the largest sensitivity from 20% to 70% RH, demonstrating the possibilities of directly printing the sensor tag on traditional packages to realize intelligent packaging at an ultra-low cost. / <p>QC 20150326</p>

L’essor considérable de la RFID s’accompagne actuellement par le développement de nombreuses technologies qui viennent compléter l’offre déjà présente tout en cherchant à répondre à de nouvelles problématiques. La RFID sans puce (ou chipless) en est un exemple ; l’objectif affiché est de réduire considérablement le prix du tag ainsi que d’augmenter significativement la quantité d’information qu’il contient de manière à pouvoir concurrencer le code à barres tout en conservant les bénéfices d’une approche de lecture flexible basée sur une communication par ondes radio. Pour répondre à la problématique de la quantité d’information d’un tag, ce travail de thèse propose une nouvelle méthode de codage basée sur la forme globale du RCS du tag. Pour ce faire, il faut être capable de réaliser des tags dont le RCS est donné, ce qui consiste à résoudre un problème inverse. Une méthode de conception basée sur l’assemblage de motifs résonants est proposée. Les principales caractéristiques de ces éléments de base (amplitude, fréquence, coefficient de qualités) sont contrôlées par des paramètres géométriques. / The important growth of RFID goes along with the development of many technologies which complement the current offer by adding new possibilities. The chipless RFID is a perfect example of such technology. The purpose of the approach is to considerably reduce the price of the tag while increasing the data encoding capacity in order to compete with the barcode. The RF link between the tag and the reader also permit a flexible reading. In order to increase the coding capacity of a chipless tag, this PHD work proposes a new coding method based on the overall shape of the electromagnetic signature. To do this, we must be able design tags for which the RCS is given in advance, which amounts to the resolution of an inverse problem. A method based on the decomposition of the RCS on a base of resonators is proposed. The main characteristics of these base elements (amplitude, frequency, quality factor) are controlled by geometric parameters.

Dans cette thèse, le concept d'identification par radiofréquence sans puce (chipless RFID) est étendu à l'authentification où chaque étiquette doit présenter une signature unique qui ne peut jamais être reproduite même si quelqu'un tente de copier l'étiquette. À cette fin, le caractère aléatoire naturel (c’est-à-dire inhérent au processus de fabrication) ainsi que les paramètres de dimension des résonateurs sont utilisés. Un tel caractère aléatoire naturel peut produire des signatures électromagnétiques (EM) uniques, éventuellement utilisées pour l'authentification. Initialement, nous avons prouvé l’idée proposée en appliquant intentionnellement les variations dimensionnelles le long des résonateurs. Différentes valeurs des variations dimensionnelles appliquées sont utilisées pour trouver la variation minimale détectable par l'approche radar sans puce RFID. De plus, une analyse statistique a été réalisée pour calculer les taux d'erreur. Par la suite, une approche par spectrogramme est proposée pour extraire des paramètres indépendants de l’aspect (c’est-à-dire la fréquence de résonance et le facteur de qualité) des étiquettes RFID sans puce. Enfin, nous avons fabriqué plusieurs résonateurs présentant un caractère aléatoire naturel (sans aucune variation dimensionnelle appliquée) afin de caractériser la performance des étiquettes sans puce pour les applications d'authentification. Des technologies de réalisation à faible coût basées sur des circuits imprimés avec un procédé de gravure chimique et l’impression à jet d’encre par une imprimante de bureau ordinaire sont utilisées. Le caractère aléatoire naturel selon les dimensions des résonateurs est également confirmé par l'analyse microscopique à l'aide d'un microscope numérique. / In this thesis, the concept of chipless radio frequency identification (RFID) is extended to the chipless authentication where each tag has to present a unique signature that can never be reproduced even if someone tries to copy the tag. For this purpose, natural randomness (i.e., inherent in the fabrication process) along dimension parameters of resonators is utilized. Such natural randomness can produce unique electromagnetic (EM) signatures that are possibly employed for authentication. Initially, we proved the proposed idea by purposely applying the dimensional variations along the resonators. Different values of the purposely applied dimensional variations are used to find the minimum detectable variation by the chipless RFID radar approach. Additionally, a statistical analysis has been performed to calculate the error rates. Subsequently, a spectrogram approach is proposed to extract aspect-independent parameters (i.e., the frequency of resonance and quality factor) of chipless RFID tags. Finally, we fabricated numerous resonators exhibiting natural randomness (without any purposely applied dimensional variations) to characterize the potential of the chipless tags for authentication applications. Low-cost realization technologies such as printed circuit board (PCB) using chemical etching process and inkjet printing using ordinary office printer are utilized. The natural randomness along the dimensions of resonators is also confirmed by the microscopic analysis using a digital microscope.

As prominent components of the Internet-of-Things (IoT) front-end, sensors capable of intelligently collecting sensing information from the surrounding environment with increasingly lower prices are required. Planar microwave chipless sensors could be a valid solution and will be the focus of this PhD research proposal. With a completely passive solution, that in its basic configuration is composed by only microstrip resonant structures and sensitive materials, this frequency-domain sensing technology results particularly adapt for the integration in smart devices. The objectives of the PhD activity will be to contribute with a further investigation of sensitive materials in the context of environmental monitoring and to test their reliability as sensitive components in controlled wired condition. The purpose is, then, to move from a wired controlled measurement to a wireless reading acquisition of the microwave sensing node response. Finally, the sensor potentialities will be further enriched by adopting fabrication techniques typical of the flexible electronics field. An inkjet printing strategy is investigated for the purpose trying to ensure good detection properties as in the case of standard fabricated tags.

Modern smartphone technology has created a myriad of opportunities in the field of RF and Microwave. Specifically, Chipless RFID sensor, compact microwave filter, antenna based on a microstrip structure, and many more. In this thesis, innovative ideas for the industrial and biomedical device has been explored. The work presents the reconfigurable filter design, Switch-beam antenna, Microwave interferometer, X-band Rotman Lens antenna, Ultra-wideband antenna based on SIW resonator, L-band Stepped Frequency Continuous Wave antenna, development of a wireless sensor system for environmental monitoring, Indoor Air Quality monitoring, and Wildfire Monitoring based on the modulated scattering technique (MST). The MST sensor probes are based on the scattering properties of small passive antennas and radiate part of the impinging electromagnetic field generated by an interrogating antenna, which also acquires the backscattered signal as information. The MST probes are able to deliver data without a radio frequency front end. They use a simple circuit that alternatively terminates the antenna probe on suitable loads to generate a low modulation signal on the backscattered electromagnetic wave. The antenna presented in this work has been designed in ADS Software by Keysight Technologies. The designed antenna has been assessed numerically and experimentally. The experimental measurement data demonstrate the effectiveness of the individual system. Simultaneously, the MST sensor system has been proposed to obtain the best performance in communication range, load efficiency, and power harvesting. The MST sensor has been fabricated and assessed in practical scenarios. The proposed prototype, able to provide a communication range of about 15 m, serves as a proof-of-concept. The acquired measurements of MST demonstrate the accuracy of the data without radio frequency front end or bulky wired connection with the same efficiency of standard wireless sensors such as radio frequency identifier (RFID) or wireless sensor networks (WSN).

Recently, Radio Frequency Identification (RFID) technology has become commonplace in many applications. It is based on storing and remotely retrieving the data embedded on the tags. The tag structure can be chipped or chipless. In chipped tags, an integrated IC attached to the antenna is biased by an onboard battery or interrogating signal. Compared to barcodes, the chipped tags are expensive because of the existence of the chip. That was why chipless RFID tags are demanded as a cheap candidate for chipped RFID tags and barcodes. As its name expresses, the geometry of the tag acts as both modulator and scatterer. As a modulator, it incorporates data into the received electric field launched from the reader antenna and reflects it back to the receiving antenna. The scattered signal from the tag is captured by the antenna and transferred to the reader for the detection process. By employing the singularity expansion method (SEM) and the characteristic mode theory (CMT), a systematic design process is introduced by which the resonant and radiation characteristics of the tag are monitored in the pole diagram versus structural parameters. The antenna is another component of the system. Taking advantage of ultra-wideband (UWB) technology, it is possible to study the time and frequency domain characteristics of the antenna used in chipless RFID system. A new omni-directional antenna element useful in wideband and UWB systems is presented. Then, a new time-frequency technique, called short-time matrix pencil method (STMPM), is introduced as an efficient approach for analyzing various scattering mechanisms in chipless RFID tags. By studying the performance of STMPM in early-time and late-time responses of the scatterers, the detection process is improved in cases of multiple tags located close to each other. A space-time-frequency algorithm is introduced based on STMPM to detect, identify, and localize multiple multi-bit chipless RFID tags in the reader area. The proposed technique has applications in electromagnetic and acoustic-based detection of targets. / Ph. D.

[pt] Estruturas baseadas em grafeno como óxido de grafeno (OG) e óxido de grafeno reduzido (OGr) vêm sendo amplamente utilizadas em aplicações de sensoriamento resistivo de gás. Entretanto, poucos projetos são efetuados utilizando métodos pervasivos e não intrusivos, que são importantes para aplicações onde intervenções podem ser problemáticas. Este trabalho apresenta a implementação de protótipos de sensores sem fio de baixo custo baseados na tecnologia de RFID sem chip, para sensoriamento de vapor de álcool, utilizando uma topologia de antena miniaturizada baseada em Metamateriais (MTMs) carregada com OGr. Simulações utilizando o método dos elementos finitos são efetuadas de forma a encontrar o melhor local para deposição das estruturas sensíveis ao vapor de álcool. É observado que a estrutura responde a variações de resistividade de OGr apenas para uma determinada faixa de valores. O tempo de redução térmica de OG necessário para atingir este espectro de valores é experimentalmente determinado, estando entre 60 e 90 min à 200 Graus Celsius. Amostras de GO são fabricadas utilizando o método de Hummer modificado, e são depositadas nos gaps das antenas. Posteriormente, são reduzidas por 60, 75 e 90 minutos. O setup de medição consistiu em medições do coeficiente de reflexão em banda X. Após um determinado tempo para estabilização, álcool isopropílico e também etanol são colocados em contato com a amostra em um recipiente fechado por 1h30, e a resposta foi observada. Resultados com sensibilidade de até 11,5 por cento foram obtidos. / [en] Graphene oxide (GO) and reduced graphene oxide (rGO) based structures have been widely applied for resistive gas sensing applications. However, few projects are developed using pervasive and non-intrusive methods, which are important for applications where intervention can be an issue. This work presents the implementation of low-cost wireless sensor prototypes based on chipless RFID technology, for alcohol vapor sensing, by using a metamaterial (MTM) based miniaturized antenna loaded with rGO. Simulations are performed using finite element method in order to find the best place to deposit the alcohol vapor sensitive structures. It is observed that the structure responds to resistivity variations only for a determined range of values. The GO reduction time necessary to reach this spectrum of values is experimentally determined, and it is found to be between 60 and 90 min at 200 Celsius degrees. GO samples are synthesized using a modified Hummer s method, and deposited in the gaps of the antenna structures. Later, they are reduced for 60, 75 and 90 min. The measurement setup consists in reflection coefficient characterization at X band frequencies. After a stabilization time, isopropyl alcohol and ethanol are put in contact with the samples in a closed container for 1h30, and the response is observed. Sensitivities up to 11,5 percent are obtained.