42 research outputs found
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
Second year technical report on-board processing for future satellite communications systems
Advanced baseband and microwave switching techniques for large domestic communications satellites operating in the 30/20 GHz frequency bands are discussed. The nominal baseband processor throughput is one million packets per second (1.6 Gb/s) from one thousand T1 carrier rate customer premises terminals. A frequency reuse factor of sixteen is assumed by using 16 spot antenna beams with the same 100 MHz bandwidth per beam and a modulation with a one b/s per Hz bandwidth efficiency. Eight of the beams are fixed on major metropolitan areas and eight are scanning beams which periodically cover the remainder of the U.S. under dynamic control. User signals are regenerated (demodulated/remodulated) and message packages are reformatted on board. Frequency division multiple access and time division multiplex are employed on the uplinks and downlinks, respectively, for terminals within the coverage area and dwell interval of a scanning beam. Link establishment and packet routing protocols are defined. Also described is a detailed design of a separate 100 x 100 microwave switch capable of handling nonregenerated signals occupying the remaining 2.4 GHz bandwidth with 60 dB of isolation, at an estimated weight and power consumption of approximately 400 kg and 100 W, respectively
The temperature wave method of measuring thermal diffusivity and thermal contact conductance
Call number: LD2668 .T4 1969 T65Master of Scienc
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Convolutional encoding-sequential decoding technique for coherent deep space telemetry link and near earth space mission
Literature review of the remote sensing of natural resources
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NASA Tech Briefs, June 1995
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Proceedings from symposia of the Technology 2002 Conference and Exposition, December 1-3, 1992, Baltimore, MD. Volume 2 features 60 papers presented during 30 concurrent sessions
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From Introduction: "This report is the first of a series intended to provide a selective overview of research and development efforts and requirements in the somewhat overlapping fields of the computer and information sciences and technologies. The projected series of reports will attempt to outline the probable range of R & D activities in the computer and information sciences and technologies through selective reviews of the literature and to develop a reasonable consensus with respect to the opinions of workers in these and potentially related fields as to areas of continuing R & D concern for research program planning or review in these areas.
Application of bit-slice microprocessors to digital correlation in spread spectrum communication systems
This thesis describes the application of commercially available microprocessors and other VLSI devices to high-speed real-time digital correlation in spread spectrum and related communication applications. Spread spectrum communications are a wide-band secure communication system that generate a very broad spectral bandwidth signal that is therefore hard to detect in noise. They are capable of rejecting intentional or unintentional jamming, and are insensitive to the multipath and fading that affects conventional high frequency systems. The bandwidth of spread spectrum systems must be large to obtain a significant performance improvement. This means that the sequence rate must be fast and therefore very fast microprocessors will be required when they are used to perform spread spectrum correlation. Since multiplication cannot be performed efficiently by microprocessors considerable work, since 1974, has been published in the literature which is devoted to minimising the requirement of multiplications in digital correlation and other signal processing algorithms. These fast techniques are investigated and implemented using general-purpose microprocessors. The restricted-bandwidth problem in microprocessor-based digital correlator has been discussed. A new implementation is suggested which uses bit-slice devices to maintain the flexibility of microprocessor-based digital correlation without sacrificing speed. This microprocessor-based system has been found to be efficient in implementing the correlation process at the baseband in the digital domain as well as the post-correlation signal processing- demodulation, detection and tracking, especiaJIy for low rate signals. A charge coupled-device is used to obtain spectral density function. An all-digital technique which is programmable for any binary waveform and can be used for achieving initial acquisition and maintaining synchronisation in spread spectrum communications is described. Many of the practical implementation problems are discussed. The receiver performance, which is measured in terms of the acquisition time and the bit-error rate, is also presented and results are obtained which are close to those predicted in the system simulations