33 research outputs found
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A Novel Long-Range Passive UHF RFID System over Twisted-pair Cable
Radio Frequency Identification (RFID) is one of the most representative, rapidly growing, and highly extendable technologies, which uses electromagnetic waves in accordance with specific communications standards and regulations to identify, track, or even localise desired objects. However, due to its high cost, limited read range, and uncertain reliability, its adoption still lags, especially in large-scale organisations. Even though an RFID distributed antenna system (DAS) can greatly improve the detection range and read rate of a single reader when system uses different combinations of antenna states with frequency and phase hopping, the lossy and heavy coaxial cables between reader and antennas still limits the system coverage and design flexibility for wide-area passive UHF RFID applications.
In order to develop a cost-efficient and flexibly-installed passive RFID DAS, a novel large-range passive UHF RFID system over twisted-pair cable is proposed in this dissertation. This new system consists of one baseband central controller and one antenna subsystem, connected by a commonly used twisted-pair cable. It is shown that transmitting/receiving low frequency baseband signals over a twisted-pair cable can significantly reduce cable attenuation and extend the communication distance. A simulation is conducted to demonstrate that frequency and phase hopping can also be remotely controlled to fit this system structure by slightly varying the frequency or phase of the input reference signal of the frequency synthesis system. The features of twisted-pair cable in terms of its low cost, light weight, and bend radius greatly improve the design and installation flexibility of an RFID system.
The implemented system is designed based on the ISO 18000-6C and EPC Class 1 Generation 2 standards, and can operate according to FCC (902-928 MHz) and ETSI (865-868MHz) regulations. The results of the measurement show the reader can achieve a sensitivity of - 94.5 dBm over 30 m Cat5e cable, and its sensitivity can still remain at around -94.2 dBm over 150 m Cat5e cable. The experimental results of tag detection show that the passive tags can be successfully detected over a 6 m wireless range following a 300 m of twisted-pair cable between the central controller and antenna. This detection range cannot be achieved by existing commercial RFID systems.
Since the transmission and reception in a RFID system are simultaneous, finite isolation of the circulator/directional coupler and environmentally dependent reflection ratio of the antenna lead to serious leakage problems. Leakage can directly cause sensitivity degradation due to saturation of the RF components. A fast leakage suppression block is developed in efforts to solve this problem. Measurements show that this new canceller can deliver an average suppression of 36.9 dB, and this excellent performance remains when the system uses frequency hopping. With help of an improved scanning algorithm, this canceller can find its optimal status within 38 ms, and this settling time is short enough for most commercial RFID readers. By reducing the number of voltage samples taken, the convergence time can be further improved.
To fully investigate this new passive UHF RFID system value, a comparison study between the new system and a commercial system is conducted. This new automatic passive UHF RFID system is confirmed to deliver high performance long-range passive tag detection. Particular advantages are shown in the fast tag read rate and capability of uplink SNR improvement. This novel system is also superior to conventional RFID systems in terms of link distance, link cost, and installation flexibility
Wireless Network Communications Overview for Space Mission Operations
The mission of the On-Board Wireless Working Group (WWG) is to serve as a general CCSDS focus group for intra-vehicle wireless technologies. The WWG investigates and makes recommendations pursuant to standardization of applicable wireless network protocols, ensuring the interoperability of independently developed wireless communication assets. This document presents technical background information concerning uses and applicability of wireless networking technologies for space missions. Agency-relevant driving scenarios, for which wireless network communications will provide a significant return-on-investment benefiting the participating international agencies, are used to focus the scope of the enclosed technical information
Surface treatments for inkjet printing onto a PTFE-based substrate for high frequency applications
Inkjet printing onto laminates for use in high frequency applications (high frequency laminates)
is challenging, due to the substrate surface roughness present after etching away the copper
layer(s). This has a detrimental effect on interconnect losses as the frequency increases. In this
paper, different surface treatments to reduce the surface roughness of a typical high frequency
laminate (RO3006) are investigated. In particular, the importance of matching the substrate
surface energy to the ink to achieve a smooth coated layer for the case of a UV cured insulator is
demonstrated. This is achievable within the parameters of heating the platen, which is a more
flexible approach compared to modifying the ink to improve the ink-substrate interaction. In
printing onto the surface modified substrates, the substrate roughness was observed to affect the
printed line width significantly. A surface roughness factor was introduced to take into account
the phenomenon by modifying the original formula of Smith et al. Lastly, the authors show that
the printed line widths are also influenced by the surface tension arising from charges present on
the surface modified substrates
Printable RF Antennas for Power Harvesting in Paper Electronics: Optimisation of Printable Materials and Substrates
This work documents the optimisation and fabrication of Radio Frequency Identification (RFID)
antennas on paper substrates to be adapted and used at 13.56 MHz. The optimisation of the antenna
layout was made by inkjet printing and after that compared with two other printing techniques:
flexography and screen printing. Commercial silver (Ag) nanoparticles (NPs) based inks were used
to obtain conductive paths. The inkjet ink was characterised by Thermogravimetric Analysis and
Differential Scanning Calorimetry (TGA-DSC) and Viscometer to know the effect of temperature
on the ink components. Absorbance measurements were also done from 200 to 800 nm to know at
which wavelength more energy is absorbed by the ink, which had a maximum peak at 320 nm.
Three different types of paper were studied (Office, INCM Coated and INCM Uncoated) and
morphologically characterised by TGA-DSC, Scanning Electron Microscopy with Energy
Dispersive Spectroscopy for surface element detection and profilometry for surface roughness
study. From the studied papers, INCM Coated paper presented an average roughness of 1015 nm
and hydrophilic behaviour with a 68.8Âş contact angle. It also showed better resistance to the
temperature when compared with Office and INCM Uncoated paper. The layout suffered different
modifications over time to ease the inkjet fabrication and reduce the pad-to-pad resistance. The
final design was used in the three printing techniques. Inkjet printing showed higher resolution and
printing quality, although the printing process and the sintering time were slower. For inkjet, INCM
Coated was the paper that better exhibited the least resistive conductive paths, reaching 106 Ί.
Office and INCM Uncoated lowest resistance values reached 140 Ί for that technique. Interesting
results were obtained by screen printing, in which all the selected substrates presented low values
between 17 Ί and 35 Ί. With this, the objective was achieved, since RFID antennas were
successfully produced, and a proof of concept was done
A Review on Antenna Technologies for Ambient RF Energy Harvesting and Wireless Power Transfer: Designs, Challenges and Applications
Radio frequency energy harvesting (RFEH) and wireless power transmission (WPT) are two emerging alternative energy technologies that have the potential to offer wireless energy delivery in the future. One of the key components of RFEH or WPT system is the receiving antenna. The receiving antenna's performance has a considerable impact on the power delivery capability of an RFEH or WPT system. This paper provides a well-rounded review of recent advancements of receiving antennas for RFEH and WPT. Antennas discussed in this paper are categorized as low-profile antennas, multi-band antennas, circularly polarized antennas, and array antennas. A number of contemporary antennas from each category are presented, compared, and discussed with particular emphasis on design approach and performance. Current design and fabrication challenges, future development, open research issues of the antennas and visions for RFEH and WPT are also discussed in this review
Cooperative Radio Communications for Green Smart Environments
The demand for mobile connectivity is continuously increasing, and by 2020 Mobile and Wireless Communications will serve not only very dense populations of mobile phones and nomadic computers, but also the expected multiplicity of devices and sensors located in machines, vehicles, health systems and city infrastructures. Future Mobile Networks are then faced with many new scenarios and use cases, which will load the networks with different data traffic patterns, in new or shared spectrum bands, creating new specific requirements. This book addresses both the techniques to model, analyse and optimise the radio links and transmission systems in such scenarios, together with the most advanced radio access, resource management and mobile networking technologies. This text summarises the work performed by more than 500 researchers from more than 120 institutions in Europe, America and Asia, from both academia and industries, within the framework of the COST IC1004 Action on "Cooperative Radio Communications for Green and Smart Environments". The book will have appeal to graduates and researchers in the Radio Communications area, and also to engineers working in the Wireless industry. Topics discussed in this book include: ⢠Radio waves propagation phenomena in diverse urban, indoor, vehicular and body environments⢠Measurements, characterization, and modelling of radio channels beyond 4G networks⢠Key issues in Vehicle (V2X) communication⢠Wireless Body Area Networks, including specific Radio Channel Models for WBANs⢠Energy efficiency and resource management enhancements in Radio Access Networks⢠Definitions and models for the virtualised and cloud RAN architectures⢠Advances on feasible indoor localization and tracking techniques⢠Recent findings and innovations in antenna systems for communications⢠Physical Layer Network Coding for next generation wireless systems⢠Methods and techniques for MIMO Over the Air (OTA) testin
Cooperative Radio Communications for Green Smart Environments
The demand for mobile connectivity is continuously increasing, and by 2020 Mobile and Wireless Communications will serve not only very dense populations of mobile phones and nomadic computers, but also the expected multiplicity of devices and sensors located in machines, vehicles, health systems and city infrastructures. Future Mobile Networks are then faced with many new scenarios and use cases, which will load the networks with different data traffic patterns, in new or shared spectrum bands, creating new specific requirements. This book addresses both the techniques to model, analyse and optimise the radio links and transmission systems in such scenarios, together with the most advanced radio access, resource management and mobile networking technologies. This text summarises the work performed by more than 500 researchers from more than 120 institutions in Europe, America and Asia, from both academia and industries, within the framework of the COST IC1004 Action on "Cooperative Radio Communications for Green and Smart Environments". The book will have appeal to graduates and researchers in the Radio Communications area, and also to engineers working in the Wireless industry. Topics discussed in this book include: ⢠Radio waves propagation phenomena in diverse urban, indoor, vehicular and body environments⢠Measurements, characterization, and modelling of radio channels beyond 4G networks⢠Key issues in Vehicle (V2X) communication⢠Wireless Body Area Networks, including specific Radio Channel Models for WBANs⢠Energy efficiency and resource management enhancements in Radio Access Networks⢠Definitions and models for the virtualised and cloud RAN architectures⢠Advances on feasible indoor localization and tracking techniques⢠Recent findings and innovations in antenna systems for communications⢠Physical Layer Network Coding for next generation wireless systems⢠Methods and techniques for MIMO Over the Air (OTA) testin