The Multitag Microwave RFID System with Extended Operation Range

The problems of radio frequency identification are discussed. It was shown that the use of passive transponders is preferable, but weak energy of system in this case reduces the operation distance and decreases the noise-immunity of the system. The problems of traditional radio-frequency identification systems are discussed. In this chapter the use of homodyne method of useful signal selecting was proposed. The augmentation signal of transponder was obtained by means of frequency shift with the help of controlled phase shifter. This solution allows to increase the energy and the noise-immunity of the system (the operation distance is increased). Furthermore, the interrogator can treat several transponders simultaneously in this case. Additionally the use of one-port transistor amplifier for increasing of operation range was proposed. The energy consumption of such amplifier and its cost are very low, but the gain of amplifier can reach 20 dB and more.

Differential Integrated Circuit Package Antenna for RFID Reader

The emphasis of this chapter is to introduce the design of the integrated circuit package antenna (ICPA), which is a compact and cost-effective antenna design method for RFID reader. The concept, the architecture, and the characterizations of the ICPA will be discussed in details. As differential circuitry dominates in RF transceiver integrated circuit design due to its good performance, microstrip antennas can be seen for use in radio systems with differential signal operation. In this chapter, the improved theory of single-ended microstrip antennas based on the cavity model is expanded to analyze the input impedance and radiation characteristics of the differentially-driven microstrip antennas and ICPA. The occurrence of the resonance for the differentially-driven microstrip antennas, which can be tuned by adjusting the ratio of the separation of the dual feeds to the free space wavelength, will be analysed. Furthermore, the frequency band selection capability of the differential ICPA will be presented.

Analysis and Design of Meander Line Dipole Antennas

A simple analytic formula, found in the literature for calculating the resonant frequency of a meander line dipole antenna (MDA) in free space from its physical parameters is described. The formula is modified to calculate the resonant frequency of an MDA on a dielectric substrate and for use as an RFID tag antenna by taking two factors into account: (i) the effects of dielectric material underneath the MDA, (ii) the special needs of an impedance matching condition in RFID tag antenna design. The parameter of relative effective permittivity for an MDA on a dielectric board, and the method for deriving this parameter, are introduced. Experiments to verify the modified formula are reported. Test results such as input impedance and reading range of an RFID tag antenna design based on an MDA on a dielectric board are provided. Following that, the radiation pattern and efficiency of an MDA either in free space or on a board are investigated.

Introduction to Chipless and Conventional Radio Frequency Identification System

The book provides a comprehensive coverage on most recent developments in chipless and conventional RFID. It covers a wide range of topics from component level design, analysis, and development, to system integration, middleware, anti-collision, and security protocols. The chipless RFID will bring revolutionary impacts on low-cost item tagging in this millennium. The RFID based sensors and RF sensors play a vital role in real time condition monitoring of objects. The designs of various chipless RFID tags and printing techniques to achieve a goal toward less than a cent tag are presented. The reading methods of RFID tags of various types, system perspective design, and analyses, detection techniques, sensor nodes for RFID system, security risk and vulnerability of the RFID technology and their remedies, anti-collision protocols, middleware and enterprise software implementation, and innovative applications of RFIDs in various fields are all presented in the book. The book will make a valuable reference in the RFID field, which has been growing exponentially.

Object Analysis with Visual Sensors and RFID

Object analysis using visual sensors is one of the most important and challenging issues in computer vision research due principally to difficulties in object representation, segmentation, and recognition within a general framework. This has motivated researchers to investigate exploiting the potential identification capability of RFID (radio frequency identification) technology for object analysis. RFID however, has a number of fundamental limitations including a short sensing range, missing tag detection, not working for all objects, and some items being just too small to be tagged. This has meant applying RFID alone has not been entirely effective in computer vision applications. To address these restrictions, object analysis approaches based on a combination of visual sensors and RFID have recently been successfully introduced. This chapter presents a contemporary review on these object analysis techniques for localisation, tracking, and object and activity recognition, together with some future research directions in this burgeoning field.

A Novel Approach in the Detection of Chipless RFID

This chapter presents a different perspective on the chipless RFID system where the chipless RFID detection problem is viewed in terms of a digital communication point of view. A novel mathematical model is presented, and a novel approach to detection is formulated based on the model. The chipless RFID tag frequency signatures are visualized as points in a signal space. Although data bits are stored in the tags using unconventional techniques, the proposed model enables the detection of these data bits through conventional robust detection methods. Through simulations it is shown that the proposed detection method has better performance compared to contemporary detection approaches.

Design of High Efficiency Power Amplifier for RFID Readers

In RFID reader systems, power amplifier plays a critical rule for efficiency enhancement. A high efficiency power amplifier may not only increase the life expectancy of portable RFID devices but also reduce the reliance on heat sinks. Heat sinks usually occupy plenty of space and lead to packing difficulties. A well-designed power amplifier with high efficiency and output power may also increase the reading range of RFID and system reliability, especially for the applications requiring long reading range (e.g. vehicle tagging in complicated traffics) or in a lossy environment (e.g. in sensing in rainy weather). This chapter systematically introduces the typical power amplifiers classified as Class A, AB, B, E, and F. The principles of Class F are emphasized due to its outstanding performance in efficiency enhancement. A practical design example is also presented, and also some recent typical techniques for improving the performances of Class F power amplifier are summarized.

Printing Techniques and Performance of Chipless Tag Design on Flexible Low-Cost Thin-Film Substrates

Radio Frequency Identification (RFID) is an emerging technology playing a vital role in modern automatic identification system. Chipless RFID is a new dimension in the field of radio-frequency application systems with immense potential to manufacture low-cost, multi-bit RFID tags for potential barcode replacement on polymer, paper, and other flexible substrates. In this chapter, the authors present a detailed overview of the printing methods, substrates, and materials used for printing chipless RFID tags. Based on the available literature, an attempt is made to review the printing and performance related issues of printed RF devices that are currently published. The basic aspects of printing of chipless tags with conductive inks are discussed in brief.

Multi-Input-Multi-Output Antennas for Radio Frequency Identification Systems

In this chapter the authors discuss the physical insight of the role of wireless communication in RFID systems. In this respect, this chapter gives a brief introduction on the wireless communication model followed by various communication schemes. The chapter also discusses various channel impairments and the statistical modeling of fading channels based on the environment in which the RFID tag and reader may be present. The chapter deals with the fact that the signal attenuations can be dealt with up to some level by using multiple antennas at the reader transmitter and receiver to improve the performance. Thus, this chapter discusses the use of transmit diversity at the reader transmitter to transmit multiple copies of the signal. Following the above, the use of receiver combining techniques are discussed, which shows how the multiple copies of the signal arriving at the reader receiver from the tag are combined to reduce the effects of fading. The chapter then discusses various modulation techniques required to modulate the signal before transmitting over the channel. It then presents a few channel estimation algorithms, according to which, by estimating the channel state information of the channel paths through which transmission takes place, performance of the wireless system can be further increased. Finally, the Antenna selection techniques are presented, which further helps in improving the system performance.

UHF RFID Reader Antenna

This chapter addresses the various design issues, requirements, and specifications in designing reader antennas for UHF RFID applications. In a typical UHF system, the RFID reader antennas are geography specific; that is, there are different antennas for different geography, namely North America, Europe, et cetera. The discussion on the design challenges and performance expectations lead to a new form of compact and broad band antenna, which will be applicable for the global UHF RFID band of 860MHz to 960 MHz. In addition, this chapter also provides potential future trends in RFID reader antenna design. The issues and challenges discussed in this chapter are envisioned to provide a roadmap to the potential challenges to be faced by a chipless RFID system.