Normalization-Free Chipless RFIDs by Using Dual-Polarized Interrogation

A reliable encoding/detection scheme for chipless radio frequency identification (RFID) tags, free from any normalization procedure, is presented. The key strategy of the present approach consists in storing the information in the difference between vertically and horizontally polarized reflection coefficients of a completely passive tag. The measured reflection coefficients are preemptively filtered in the time domain to remove most of harmful effects due to the antenna coupling and environment multipath, and finally they are subtracted to obtain the differential response. A couple of chipless tag configurations suitable for providing the desired spectral response are presented. The resonators consist of an artificial impedance surface comprising either concentric rectangular loop resonators or square loop resonators loaded with stubs. The presented approach is experimentally verified in a non-anechoic environment, and its robustness is proved. This calibration-free approach could pave the way to practical applicability of chipless RFID tags in realistic scenarios with unknown response

Design de circuitos RFID multi-ressonantes sem chip como substitutos dos códigos de barras

The chipless RFID technology , appears from an e ort to design low-cost RFID tags without the use of traditional silicone Application Specific Integrated Circuits (ASICs) that are the price bottleneck of the typicall RFID technology. In this way, tags become fully passive and without any active processing unit, thus the Chipless RFID system have more similarities with the Radio Detection And Ranging (RADAR) systems than with the common RFID systems. This dissertation sheds light on the problems and challenges that the RFID technology has as replacement of the optical barcode labels, discuss the state of the art of the chipless RFID technology and presents a model to describe the relationship between the multi-resonant circuit resonant frequency and the resonant spirals length. Finally, a chipless RFID system is simulated making use of the fractional Fourier Transform as means to separate linear frequency modulated signals that collide in both time and frequency domain. The results achieved with dissertation not only aid designers with the synthesis of multi-resonant circuits but also prove the reliability of the use of the fractional Fourier Transform as a means of manipulating the time-frequency domain and successfully recovering individual tags' ID from a signal containing more than one collided backscattered signal.A tecnologia de RFID sem chip, surgiu de um esforço para obter etiquetas RFID de baixo custo sem o uso de circuitos integrados de aplicação especifica (ASICs) que são a restrição à diminuição dos preço dos tipicos sistemas RFID. Desta forma, as tags tornam-se totalmente passivas e sem nenhuma unidade de processamento ativa, passando, os sistemas RFID sem chip a ter mais semelhanças com os sistemas de Radio Detection And Ranging (RADAR) do que com os sistemas RFID comuns. Esta dissertação esclarece os problemas e desafios que a tecnologia RFID enfrenta enquanto substituta das etiquetas de código de barras apresentando também o estado da arte da tecnologia RFID sem chip. Também apresenta e propõe um modelo para descrever a relação entre a frequência de ressonância do circuito multi-ressonante e o comprimento das espirais ressonantes. Finalmente, um sistema RFID sem chip é simulado usando a transformada fracionária de Fourier como meio de separar sinais modulados linearmente em frequência que colidem simultaneamente no domínio do tempo e da frequência. Os resultados alcançados com esta dissertação por um lado ajudam os projetistas com a síntese de circuitos multi-ressonantes e por outro provam a confiabilidade do uso da transformada fracionária de Fourier como um meio de manipular o domínio tempo-frequência para recuperar com sucesso informa ção individual de ID a partir de um sinal que contém mais de um sinal transmistido de uma etiqueta sem chip.Mestrado em Engenharia Eletrónica e Telecomunicaçõe

Chipless RFID sensor tag system with microstrip transmissionline based ID generation schemes

This dissertation presents a chipless radio frequency identification (RFID) sensor tag system consisting of passive chipless RFID sensor tags and specialized reader. The chipless sensor tags are fabricated on a flexible substrate and contain an ID generation circuit, a sensor, and a microstrip antenna. The ID generation circuit consists of meandered microstrip transmission lines and uses a novel reflection and delay based ID generation scheme. The scheme, using an input RF pulse, constructs an on-off keying (OOK) or pulse position modulated (PPM) signal pattern representing a unique ID code. Two transmission lines and OOK representation are used and the generation of ten different ID codes are demonstrated. The integrated ID generation circuit, sensor, and antenna use a single transmission line and PPM representation, and demonstrate the generation of eight different ID codes. However, the presented schemes allow the generation of higher combinations of bits. A practical method to measure radar cross section (RCS) parameters of antennas that provides complete and more accurate information on scattering properties of antennas, essential for chipless sensor tag design, is presented. The new method uses minimum mean square error estimation solution of a derived received backscattered signal power equation and provides load independent structural-mode RCS, antenna-mode RCS, and relative phase factor of the measured antenna. Two configurations of the chipless sensor tags configuration-I (conf-I) and configuration-II (conf-II) are presented. In conf-I tags, sensors are connected as a load to the antenna and the sensor information is amplitude modulated in the backscattered signal. The testing with conf-I temperature sensor tag resulted in a 28% amplitude change when the temperature at the tag changes from 27°C to 140°C. In conf-II tags, sensors are connected as load to the ID generation circuit and the sensor information is phase modulated in the antenna-mode scattered signal. With the conf-II ethylene sensor tag, a phase change of 33° is observed when the ethylene concentration at the tag changes from 0 to 100 ppm. The specialized reader system is comprised of an analog reader that wirelessly communicates with the sensor tags and a single board computer that computes the sensor information from the received signal. The reader system constructs a 96 bit serialized global trade item number (SGTIN-96) electronic product code (EPC) format unique RFID tag data frame, including 16 bit sensor information, and makes the information available on a secure web interface accessible from cyberspace. The presented sensor tag system has the advantages of passive and chipless sensor tag operation, while offering a wide range of sensors types for integration. Moreover, it offers a viable alternative solution to existing active as well as passive RFID sensor tag systems (eg. SAW based RFID sensor tag systems)

Design of an Ultra-wideband Radio Frequency Identification System with Chipless Transponders

The state-of-the-art commercially available radio-frequency identification (RFID) transponders are usually composed of an antenna and an application specific integrated circuit chip, which still makes them very costly compared to the well-established barcode technology. Therefore, a novel low-cost RFID system solution based on passive chipless RFID transponders manufactured using conductive strips on flexible substrates is proposed in this work. The chipless RFID transponders follow a specific structure design, which aim is to modify the shape of the impinged electromagnetic wave to embed anidentification code in it and then backscatter the encoded signal to the reader. This dissertation comprises a multidisciplinary research encompassing the design of low-cost chipless RFID transponders with a novel frequency coding technique, unlike usually disregarded in literature, this approach considers the communication channel effects and assigns a unique frequency response to each transponder. Hence, the identification codes are different enough, to reduce the detection error and improve their automatic recognition by the reader while working under normal conditions. The chipless RFID transponders are manufactured using different materials and state-of-the-art mass production fabrication processes, like printed electronics. Moreover, two different reader front-ends working in the ultra-wideband (UWB) frequency range are used to interrogate the chipless RFID transponders. The first one is built using high-performance off-theshelf components following the stepped frequency modulation (SFM) radar principle, and the second one is a commercially available impulse radio (IR) radar. Finally, the two readers are programmed with algorithms based on the conventional minimum distance and maximum likelihood detection techniques, considering the whole transponder radio frequency (RF) response, instead of following the commonly used approach of focusing on specific parts of the spectrum to detect dips or peaks. The programmed readers automatically identify when a chipless RFID transponder is placed within their interrogation zones and proceed to the successful recognition of its embedded identification code. Accomplishing in this way, two novel fully automatic SFM- and IRRFID readers for chipless transponders. The SFM-RFID system is capable to successfully decode up to eight different chipless RFID transponders placed sequentially at a maximum reading range of 36 cm. The IR-RFID system up to four sequentially and two simultaneously placed different chipless RFID transponders within a 50 cm range.:Acknowledgments Abstract Kurzfassung Table of Contents Index of Figures Index of Tables Index of Abbreviations Index of Symbols 1 Introduction 1.1 Motivation 1.2 Scope of Application 1.3 Objectives and Structure Fundamentals of the RFID Technology 2.1 Automatic Identification Systems Background 2.1.1 Barcode Technology 2.1.2 Optical Character Recognition 2.1.3 Biometric Procedures 2.1.4 Smart Cards 2.1.5 RFID Systems 2.2 RFID System Principle 2.2.1 RFID Features 2.3 RFID with Chipless Transponders 2.3.1 Time Domain Encoding 2.3.2 Frequency Domain Encoding 2.4 Summary Manufacturing Technologies 3.1 Organic and Printed Electronics 3.1.1 Substrates 3.1.2 Organic Inks 3.1.3 Screen Printing 3.1.4 Flexography 3.2 The Printing Process 3.3 A Fabrication Alternative with Aluminum or Copper Strips 3.4 Fabrication Technologies for Chipless RFID Transponders 3.5 Summary UWB Chipless RFID Transponder Design 4.1 Scattering Theory 4.1.1 Radar Cross-Section Definition 4.1.2 Radar Absorbing Material’s Principle 4.1.3 Dielectric Multilayers Wave Matrix Analysis 4.1.4 Frequency Selective Surfaces 4.2 Double-Dipoles UWB Chipless RFID Transponder 4.2.1 An Infinite Double-Dipole Array 4.2.2 Double-Dipoles UWB Chipless Transponder Design 4.2.3 Prototype Fabrication 4.3 UWB Chipless RFID Transponder with Concentric Circles 4.3.1 Concentric Circles UWB Chipless Transponder 4.3.2 Concentric Rings UWB Chipless RFID Transponder 4.4 Concentric Octagons UWB Chipless Transponders 4.4.1 Concentric Octagons UWB Chipless Transponder Design 1 4.4.2 Concentric Octagons UWB Chipless Transponder Design 2 4.5 Summary 5. RFID Readers for Chipless Transponders 5.1 Background 5.1.1 The Radar Range Equation 5.1.2 Range Resolution 5.1.3 Frequency Band Selection 5.2 Frequency Domain Reader Test System 5.2.1 Stepped Frequency Waveforms 5.2.2 Reader Architecture 5.2.3 Test System Results 5.3 Time Domain Reader 5.3.1 Novelda Radar 5.3.2 Test System Results 5.4 Summary Detection of UWB Chipless RFID Transponders 6.1 Background 6.2 The Communication Channel 6.2.1 AWGN Channel Modeling and Detection 6.2.2 Free-Space Path Loss Modeling and Normalization 6.3 Detection and Decoding of Chipless RFID Transponders 6.3.1 Minimum Distance Detector 6.3.2 Maximum Likelihood Detector 6.3.3 Correlator Detector 6.3.4 Test Results 6.4 Simultaneous Detection of Multiple UWB Chipless Transponders 6.5 Summary System Implementation 7.1 SFM-UWB RFID System with CR-Chipless Transponders 7.2 IR-UWB RFID System with COD1-Chipless Transponders 7.3 Summary Conclusion and Outlook References Publications Appendix A RCS Calculation Measurement Setups Appendix B Resistance and Skin Depth Calculation Appendix C List of Videos Test Videos Consortium Videos Curriculum Vita

Advanced Radio Frequency Identification Design and Applications

Radio Frequency Identification (RFID) is a modern wireless data transmission and reception technique for applications including automatic identification, asset tracking and security surveillance. This book focuses on the advances in RFID tag antenna and ASIC design, novel chipless RFID tag design, security protocol enhancements along with some novel applications of RFID

Realistic chipless RFID: protocol, encoding and system latency

Chiplose Identifikation über Funkfrequenzen, RFID (engl., Radio Frequency IDentification) ist eine vielversprechende Technology, der man die Fähigkeit zuschreibt, in naher Zukunft den optischen Barcode zu ersetzen. Letztgenannter hat Einschränkungen durch i) RFID Tags sind bei nicht vorhandener Sichtverbindung (engl. Non-Line-Of-Sight, NLOS) auch nicht lesbar; ii) das Scannen der Barcodes benötigt in den meisten Fällen manuelles Eingreifen; iii) es ist unmöglich mehrere Barcodes gleichzeitig auszulesen; iv) und als Folge davon entsprechende Verzögerungen beim Auslesen größerer Mengen von Barcodes, da alle einzeln gescannt werden müssen. Die Beiträge der vorliegenden Dissertation konzentrieren sich auf drei Schwerpunkte von frequenzcodierten (engl. frequency coded, FC) chiplosen RFID Systemen. Der erste Schwerpunkt ist die gleichzeitige Identifikation von mehreren RFID Tags und kümmert sich um den Fall, dass sich mehrere RFID Tags in der Lesezone des RFID Lesegerätes befinden. Der zweite Aspekt betrifft die Verzögerung des Systems, die Zeit, das Lesegerät zum Identifizieren der RFID Tags benötigt. Und drittens die Coding Kapazität des Systems, sie ist verantwortlich für die zu erreichende Bittiefe des RFID Systems. Ein real umsetzbares RFID System erfordert Lösungen in allen drei Aspekten. Da chiplose RFID Tags keine integrierten Schaltungen (ICs) und somit auch keine Speicherbausteine besitzen, ist die Anzahl der auf dem RFID Tag speicherbaren Bits begrenzt. Und als Folge davon sind die Standards und Protokolle, die für die herkömmlichen chipbehafteten RFID Systeme entwickelt worden, nicht auf chiplose RFID Systeme übertragbar. Das wesentliche Ziel des ersten Beitrages ist die Einführung eines neuen Multi-Tag Antikollisionsprotokolls, das auf der Modulation der Notchposition (engl. Notch Position Modulation, NPM) und Tabellen (engl. Look-Up-Table, LUT) zur Bestimmung der Netzwerk- und MAC- Layer des chiplosen RFID Systems basiert. Die erste Generation der vorgeschlagenen Protokolls (Gen-1) baut auf einer Zweiteilung des zur Verfügung stehenden Spektrums auf. Im unteren Frequenzbereich, als Präambel Bandbreite bezeichnet, wird jedem RFID Tag seine individuelle Frequenzverschiebung übermittelt und im zweiten Bereich, der sogenannten Frame Bandbreite, ist die Identifikationsnummer (ID) des RFID Tags hinterlegt. Mit dieser Anordnung lässt sich jegliche Interferenz zwischen den verschiedenen RFID Tags unterbinden, da sich die Antworten der RFID Tags nicht gegenseitig überlagern. Die zweite Generation dieses Protokolls bringt eine Verbesserung sowohl bei der Coding Kapazität als auch bei der Nutzung des zur Verfügung stehenden Frequenzspektrums. Dies wird dadurch erreicht, dass die ID des RFID in einer Tabelle im Lesegerät gespeichert wird. Die individuelle Frequenzverschiebung dient dabei als Adresse für die gespeicherten IDs. Dieser Schritt vereinfacht die Komplexität der Struktur des RFID Tags signifikant, während gleichzeitig die Erkennungswahrscheinlichkeit erhöht wird. Des Weiteren werden die Key Performance Indikatoren untersucht um die Leistungsfähigkeit der Protokolle zu beweisen. Beide Protokollversionen werden modelliert und in einer Umgebung mit 10 chiplosen RFID Tags simuliert, um die Randbedingungen für die Entwicklung der RFID Tags und des RFID Lesegerätes zu ermitteln. Außerdem wird eine neuartige Testumgebung für ein MultiTag Ultra Breitband (engl. ultra wideband UWB) RFID System unter realen Testbedingungen basierend auf einem Software Defined Radio (SDR) Ansatz entwickelt. In dieser Testumgebung werden sowohl die gesendeten Signal als auch Detektierungstechniken, Leerraum Kalibrierung zur Reduzierung der Streustrahlung und die Identifikationsprotokolle untersucht. Als zweiter Schwerpunkt dieser Arbeit werden neue Techniken zur Reduzierung der Systemlaufzeit (engl. System Latency) eingeführt. Das Ziel dabei ist, die Zeit, die das RFID Lesegerät zum Erkennen aller in Lesereichweite befindlichen chiplosen FC RFID Tags braucht, zu verkürzen. Der Großteil der Systemlaufzeit wird durch das gewählte Frequenzscanverfahren, durch die Anzahl der Mittelungen zur Eliminierung der umgebenden Streustrahlung und durch die Dauer eines Frequenzsprungs bestimmt. In dieser werden dazu ein adaptives Frequenzsprungverfahren (engl. adaptive frequency hopping, AFH) sowie ein Verfahren Mittels adaptiver gleitender Fensterung (engl. adaptive sliding window, ASW) eingeführt. Das ASW Verfahren ist dabei im Hinblick auf die Identifizierung der RFID Tags nach dem Gen-1 Protokoll entwickelt, da es ein gleitendes Fenster zur Detektierung der Notches mit einer variablen Breite zum Auslesen der ID erfordert. Im Gegensatz dazu wird das Auffinden der im Gen-2 Protokoll verwendeten Notchpattern durch das AFH Verfahren verbessert. Dies wird über variable Frequenzsprünge, die auf die jeweiligen Notchpattern optimiert werden, erreicht. Beide Verfahren haben sich als effektiv sowohl im Hinblick auf die Systemlaufzeit als auch auf die Genauigkeit erwiesen. Das ASW und das AFH Verfahren wurden dazu in der oben erwähnten Testumgebung implementiert und mit dem klassischen Frequenzsprungverfahren, feste feingraduierte Frequenzschritte, verglichen. Die Experimente haben gezeigt, dass das vorgeschlagene AFH Verfahren in Kombination mit ASW zu einer beachtlichen Reduzierung der Systemlaufzeit von 58% führen. Das Ziel des dritten Schwerpunkts dieser Arbeit ist die Einführung einer neuartigen Technik zur Erhöhung der Informationsdichte (engl. Coding capacity) in einem chiplosen FC RFID Systems. Die hierfür vorgeschlagene Modulation der Notchbreite (engl. notch width modulation, NWM) ermöglicht die Kodierung von 4 Bits (16 Zuständen) pro Resonator in dem die Notchbreite und die dazugehörige Frequenzlage ausgenutzt werden. Für jeden Notch werden 150MHz Bandbreite reserviert, innerhalb derer das Codebit durch eine bestimmte Bandbreiten an unterschiedlichen Frequenzen bestimmt wird Cj ( fk,Bl). Das bedeutet, bei einer Arbeitsfrequenz im Bereich von 2–5 GHz können so 80 Bits realisiert werden. Des Weiteren wurde eine smarte Singulärwertzerlegung (engl. smart singular value decomposition, SSVD) Technik entwickelt, um die Notchbreite zu ermitteln und eine geringe Fehlerwahrscheinlichkeit zu garantieren. Die Nutzung von Blockcodes zur Behebung von Fehlern wurde untersucht, um den größtmöglichen Nutzen aus der so gewonnene Bittiefe zu erzielen. Als Folge konnte eine große Bittiefe mit einer hohen Lesegenauigkeit bei vereinfachtem Aufbau des Lesegeräts erzielt werden. Außerdem wurde eine neuartige RFID Tag Struktur entworfen, die bei einer Größe von 4× 5 cm2 eine Codedichte von 4 Bits/cm2 erreicht. Verschiedene RFID Tag Konfigurationen wurden erstellt und das neu eingeführte Codierungsverfahren mit Hilfe von elektromagnetischen (EM) Simulation und der bereits erwähnten Testplattform überprüft. Die erzielten Ergebnisse ermöglichen ein widerstandsfähiges RFID System in einer realen Umgebung. Alle vorgeschlagenen Beiträge sind durch analytische Modelle, Simulationen und Messungen auf mögliche Probleme und die Grenzen einer Realisierung unter realistischen Bedingungen geprüft worden.Chipless Radio Frequency IDentification (RFID) is a promising technology predicted to replace the optical barcode in the near future. This is due to several problematic issues i) the barcode cannot read Non-Line-Of-Sight (NLOS) tags; ii) each barcode needs human assistance to be read; iii) it is impossible to identify multiple tags at the same time; and iv) the considerable time delay in case of massive queues because different types of objects need to be serially scanned. The contributions included in this dissertation concentrate on three main aspects of the Frequency Coded (FC) chipless RFID system. The first one is the multi-tag identification, which deals with the existence of multiple tags in the reader’s interrogation region. The second aspect is the system latency that describes the time the reader needs to identify the tags. Finally, there is the coding capacity that is responsible for designing a chipless tag with larger information bits. The aim of these aspects is to realize a chipless RFID system. Since the chipless tags are memoryless as they do not include Integrated Circuits (ICs), the number of bits to be stored in the chipless tag is limited. Consequently, the current RFID standards and protocols designed for the chipped RFID systems are not applicable to the chipless systems. The main objective of the first contribution is to introduce novel multi-tag anti-collision protocols based on Notch Position Modulation (NPM) and Look-Up-Table (LUT) schemes determining the network and MAC layers of the chipless RFID systems. The first generation of the proposed protocol (Gen-1) relies on dividing the spectrum into two parts; the first one is the preamble bandwidth that includes a unique frequency shift for each tag. The second part is the frame bandwidth which represents the tag ID. The tag ID is obtained based on the predefined frequency positions, making use of the unique frequency shift. Consequently, the interference is avoided as there will not be any overlap between the tags’ responses. The second generation of the protocol (Gen-2) introduces an improvement in the spectrum utilization and coding capacity. This is realized by transferring the tag-ID to be stored in a table in the main memory of the reader (look-up-table). The unique shift of each tag represents the address of the tag’s ID. Therefore, the complexity of the tag structure will be significantly reduced with an enhanced probability of detection. Furthermore, the key performance indicators for the chipless RFID system are explored to validate the protocol’s performance. Both protocols are modeled and simulated to identify 10-chipless tags in order to set the regulations of the tag and reader design. Moreover, a novel real-world testbed for a multi-tag Ultra Wideband (UWB) chipless RFID system based on Software Defined Radio (SDR) is introduced. In this testbed, all the signaling schemes related to the transmitted signal, the detection techniques, the empty room calibration for the clutter removal process, and the identification protocols are applied. The aim of the second aspect is to introduce novel techniques that reduce the time required by the reader to identify the FC chipless RFID tags existent in the reader’s interrogation region. This time delay is called system latency. The main parameters that significantly affect the overall system latency are the frequency scanning methodology, the number of spectrum scanning iterations for the clutter removal process, and the hop duration. Therefore, the Adaptive Frequency Hopping (AFH) and the Adaptive Sliding Window (ASW) methodologies are proposed to meet the requirements of the FC chipless RFID tags. Regarding the ASW technique, it is suitable to identify the tags using the Gen-1 protocol which utilizes a sliding window (for detecting the notch) with an adaptive size to extract the tag’s-ID. The second adaptive methodology, AFH, can identify the tags with the Gen-2 protocol by using a variable frequency step that fits the corresponding notch patterns. These techniques are proven to be efficient for the chipless RFID systems with regard to latency and accuracy. Likewise, the designed AFH and ASW technique’s performance is compared to the classical Fixed Frequency Hopping (FFH) methodology with a fine frequency step to validate the accuracy of the proposed techniques. A real-world SDR based testbed is designed and the proposed adaptive algorithms as well as the classical FFH methodology are implemented. The experiments show that the proposed AFH combined with the ASW algorithms significantly reduce the system latency by 58%. The goal of the third aspect is to introduce a novel technique that increases the coding capacity of the FC chipless RFID system. The proposed Notch Width Modulation (NWM) scheme encodes 4 bits (16-combinations) per single resonator exploiting the notch bandwidth and its corresponding frequency position. Furthermore, each notch can reserve a window with a bandwidth of 150 MHz and inside this window the notch can obtain a certain bandwidth with a specific resonant frequency constructing the coding pairs Cj ( fk,Bl). Hence, 80-bits could be achieved at the operating frequency 2–5 GHz, preserving the operating frequency bandwidth. Also, a Smart Singular Value Decomposition (SSVD) technique is designed to estimate the notch bandwidth and to ensure a low probability of error. In addition, the utilization of a linear block code as an error correcting code is explored to make the best use of the obtained coding gain. Consequently, a high encoding efficiency and an accurate detection can be achieved in addition to a simplified reader design. Moreover, a novel 4× 5 cm2 tag structure is designed to meet the requirements of the NWM coding technique achieving a coding density of 4 bits/cm2. Different tag configurations are manufactured and validated by measurements using the SDR platform. The introduced coding methodology is conclusively validated using Electromagnetic (EM) simulations and real-world testbed measurements. The considered achievements for the proposed aspects offer a robust chipless RFID system that can be considered in real scenarios. Furthermore, all the proposed contributions are validated using analytical modeling, simulation and measurements in order to list their difficulties and limitations

Applications of Antenna Technology in Sensors

During the past few decades, information technologies have been evolving at a tremendous rate, causing profound changes to our world and to our ways of living. Emerging applications have opened u[ new routes and set new trends for antenna sensors. With the advent of the Internet of Things (IoT), the adaptation of antenna technologies for sensor and sensing applications has become more important. Now, the antennas must be reconfigurable, flexible, low profile, and low-cost, for applications from airborne and vehicles, to machine-to-machine, IoT, 5G, etc. This reprint aims to introduce and treat a series of advanced and emerging topics in the field of antenna sensors

Desenvolvimento de sistema de radiofrequência para identificação de cédulas monetárias e documentos

Orientador: Hugo Enrique Hernández-FigueroaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de ComputaçãoResumo: Este trabalho descreve o desenvolvimento de um sistema de radiofrequência, eficaz e de baixo custo, para identificação de cédulas monetárias e documentos com a intenção de evitar falsificações. O sistema proposto é baseado nas tecnologias de linha de microfita e RFID sem chip, porém, a identificação é feita através do contato do objeto com a leitora. Para que essa identificação ocorra, na leitora, ressoadores em formato espiral são dispostos próximos a uma linha de transmissão, cada ressoador representando um bit de dado, e ressoam livremente até que uma cédula ou documento seja colocada em contato e devidamente alinhada. Cada cédula ou documento deve possuir uma marca metálica impressa em camada interna, pois dificulta falsificações e as ondas eletromagnéticas conseguem atravessar o papel, de forma que cada marca defina o código binário de cada objeto, uma vez que essas marcas metálicas suprimem as ressonâncias dos ressoadores situados na leitora. Em outras palavras, as marcas metálicas transformam o estado do bit de dado, bit 0 ou 1, correspondendo aos estados de presença e ausência de ressonância, respectivamente. O sistema também tem potencial para aumento do volume de codificação de dados com a possibilidade do sistema ternário, quando as ressonâncias possuem três estados. Resultados de simulações e resultados de medições também são apresentados neste trabalhoAbstract: This work describes the development of a low-cost and efficient radiofrequency system for banknotes and documents identification intending to avoid counterfeiting. The proposed system is based on the microstrip and chipless RFID technologies; however, the identification is carried out through the contact of the object with the reader. In order to make this possible, the spiral resonators in the reader are placed next to a transmission line, each resonator represents a data bit, they resonate freely until a banknote or a document is placed and aligned properly. Each banknote or document must have a metallic mark printed on its inner layer, because it makes falsification difficult and the electromagnetic waves can cross the paper, in such a way that each metallic mark establishes a binary code. The metallic marks suppress the resonances of the resonators located in the reader. In other words, the marks can change the bits state, 0 or 1, corresponding to the presence and absence of resonance, respectively. The system also has the potential to increase the volume of data encoding with the possibility of the ternary system, when the resonances have three states. Simulation and measurement results are also presented in this workMestradoTelecomunicações e TelemáticaMestre em Engenharia ElétricaCAPE

Applications of Machine Learning Strategy for Wireless Power Transfer and Identification

The objective of my research is to propose and demonstrate Machine Learning (ML) applications of wireless power transfer and identification technology. Several works describe the implementation of a ML strategy based on 1) the use of Neural Networks (NN) for real-time range-adaptive automatic impedance matching of Wireless Power Transfer (WPT) applications, 2) the Naive Bayes algorithm for the prediction of the drone’s position, thus enhancing the WPT efficiency, and 3) the Support Vector Machine (SVM) classification strategy for read/interrogation enhancement in chipless RFID applications. The ML approach for the effective prediction of the optimal parameters of the tunable matching network, and classification range-adaptive transmitter coils (Tx) is introduced, aiming to achieve an effective automatic impedance matching over a wide range of relative distances. A novel WPT system consisting of a tunable matching circuit and 3 Tx coils which have different radius controlled by trained NN models is characterized. A proof-ofconcept WPT platform which allows the accurate prediction of the drone’s position based on the flight data utilizing ML classification using the Naive Bayes algorithm is also given. A ML-based approach for classification and of detection tag IDs has been presented, which can perform effective transponder readings for a wide variety of ranges and contexts, while providing high tag-ID detection accuracy. A SVM algorithm was trained using measurement data, and its accuracy was tested and characterized as a function of the included training data. In summary, this research sets a precedent, opening the door to a rich and wide area of research for the implementation of ML methods for the enhancement of WPT and chipless RFID applications.Ph.D