Passive Radio Frequency Identification Transponder Research Articles

Dielectric Waveguide Filled With Particulate Media for Ultrahigh Frequency (UHF) Radio Frequency Identification (RFID) Applications

Radio frequency identification (RFID) is a wireless communication technique that has a wide variety of applications in many fields. In some cases, the read range of the RFID transponder is a limiting factor to the application; thus, it is desired that the read range of a given RFID system be maximized. This paper presents a method to extend the read range of UHF RFID signal (860-960 MHz) by using cost-effective dielectric particulate materials (e.g., dry sand) as filler in dielectric waveguides, which is useful for applications that employ UHF RFID as a sensing or communication tool that need long read ranges, e.g., underground pipeline corrosion monitoring or leak detection. Reading tests conducted in both laboratory (air) and underground showed that the transmission of the UHF RFID signal through dielectric particulate media can considerably extend the read range of passive RFID transponders, which makes it a good material choice for the manufacturing of wireless monitoring systems for underground infrastructures. Classic waveguide theories developed by Marcatili and Emslie et al. were modified to analyze the transmission of the UHF RFID signal in the waveguide filled with dielectric particulate media. Reasonably good agreement was observed between the measured and calculated power values.

A Blind Calibration Method for Phase-of-Arrival-Based Localization of Passive UHF RFID Transponders

Phase-of-arrival-based localization systems for passive ultrahigh frequency (UHF) radio-frequency identification (RFID) transponders must typically be calibrated to account for unknown phase offset values. Usually, reference measurements are performed using known tag positions. However, if the measurement scenario changes or other types of transponders are used, the system must be recalibrated. This paper introduces an automatic blind calibration method based on a Viterbi algorithm that requires no reference measurements. With this approach, the phase offset values are determined autonomously based on the measurement data set without any prior knowledge of the transponder positions, which are also estimated. To prove the calibration approach, a multichannel system demonstrator was used comprising a commercial off-the-shelf RFID reader, conventional passive UHF RFID tags, eight transceiver front ends, baseband hardware, and signal processing. Measurements were carried out in a 2-D indoor office environment, which was defined to be 3.5 m $\times2.5$ m. Compared with the common exhaustive calibration method using reference measurements at known tag positions, the automatic blind Viterbi-based approach offers similar results with a root-mean-square deviation of the phase offset values of 0.33 rad, which corresponds to an electrical length of 18 mm. Regarding the localization, the experiments showed accurate results with a root-mean-square error of 56 mm and a median absolute error of 21 mm.

Uncertainties in assessing tillage erosion – How appropriate are our measuring techniques?

Tillage erosion on arable land is a very important process leading to a net downslope movement of soil and soil constitutes. Tillage erosion rates are commonly in the same order of magnitude as water erosion rates and can be even higher, especially under highly mechanized agricultural soil management. Despite its prevalence and magnitude, tillage erosion is still understudied compared to water erosion. The goal of this study was to bring together experts using different techniques to determine tillage erosion and use the different results to discuss and quantify uncertainties associated with tillage erosion measurements. The study was performed in northeastern Germany on a 10m by 50m plot with a mean slope of 8%. Tillage erosion was determined after two sequences of seven tillage operations. Two different micro-tracers (magnetic iron oxide mixed with soil and fluorescent sand) and one macro-tracer (passive radio-frequency identification transponders (RFIDs), size: 4×22mm) were used to directly determine soil fluxes. Moreover, tillage induced changes in topography were measured for the entire plot with two different terrestrial laser scanners and an unmanned aerial system for structure from motion topography analysis. Based on these elevation differences, corresponding soil fluxes were calculated. The mean translocation distance of all techniques was 0.57m per tillage pass, with a relatively wide range of mean soil translocation distances ranging from 0.39 to 0.72m per pass. A benchmark technique could not be identified as all used techniques have individual error sources, which could not be quantified. However, the translocation distances of the macro-tracers used were consistently smaller than the translocation distances of the micro-tracers (mean difference=−26±12%), which questions the widely used assumption of non-selective soil transport via tillage operations. This study points out that tillage erosion measurements, carried out under almost optimal conditions, are subject to major uncertainties that are far from negligible.

RFID applied to the cataloguing of a collection of historical plaster moulds

Abstract This research work arises from the issue of the total absence of a catalogue of the historical moulds belonging to the Richard-Ginori porcelain factory located in Sesto Fiorentino (Italy). A methodology for the cataloguing of the moulds was developed and a system to support such a process was designed. This system exploits radio frequency identification (RFID) technologies for the identification of the historical moulds stored on shelves of a huge warehouse at the factory. These moulds, made of plaster, are frail and need to be handled with care: therefore, the identification of their content has to be carried out without moving or opening them. The use of passive RFID transponders (RFID tags) has allowed to solve the problem in a simple and low cost way through a hand-held RFID reader, which is able to communicate with a data system where the information about each mould is stored. Besides that, since the shelves where the historical moulds are stored are difficult to reach, the system is able to find where the moulds are situated.

Indoor Navigation System based on Passive RFID Transponder with Digital Compass for Visually Impaired People

Conventionally, visually impaired people using white cane or guide dog for traveling to desired destination. However, they could not identify their surround easily. Hence, this paper describes the development of navigation system which is applied to guide the visually impaired people at an indoor environment. To provide an efficient and user-friendly navigation tools, a navigation device is developed by using passive radio frequency identification (RFID) transponders which are mounted on the floor such as on tactile paving to build such as RFID networks. The developed navigation system is equipped with a digital compass to facilitate the visually impaired people to walk properly at right direction especially when turning process. The idea of positioning and localization with the digital compass and direction guiding through voice commands is implemented in this system. Some experiments also done which is focused on the calibration of the digital compass and relocates the visually impaired people back to the right route if they are out of the direction. Besides, a comparison between two subjects which are human and a mobile robot is made to check the validity of the developed navigation system. As the result, the traveling speed of human and mobile robot is obtained from the experiment. This project is beneficial to visually impaired people because the navigation device designed with voice commands will help them to have a better experience, safer and comfortable travel.

Large-Signal Measurements and Nonlinear Characterization of an Analog Frontend for Passive UHF CMOS RFID Transponders

This work focuses on the comprehensive measurement-based nonlinear characterization of an integrated analog frontend, which is implemented into a passive multifunctional radio-frequency-identification (RFID) transponder. It explains the necessity and the practical execution of large-signal characterization and nonlinear analyses of the frontend at ultra-high-frequencies. The fundamentals of the implemented source-pull measurement setup are described in detail and the results of selected measurements are presented. To the authors knowledge, this is the first time that a passive RFID frontend is characterized by nonlinear large-signal measurements.

The Performance Comparison of Sub-1GHz Wireless Personal Area Monitoring Systems

This paper presents a brand new hardware framework of wireless personal area monitoring system (WPAMS) in order to form a point-to-point simply connected personal area identification network with the applications of ubiquitous monitoring personal valuable belongings. The WPAMS consists of sub-1GHz radio frequency identification (RFID) interrogator subsystem, antenna subsystem and passive RFID transponder subsystem with salient features of low-cost, tiny and power-efficient. The hardware frameworks of two commercial interrogator prototypes have been identified and simulated. With the connection of 5.7dBi right-hand circularly polarized antenna and in the adherence of local power regulation (within 1watt), the identified range of all types of commercial transponders from sideward and upward directions can be reached to 2 meters. The current PCB size of interrogator is 88mm45mm and can be reduced in the near future.

An efficient 2.4GHz radio frequency identification (RFID) in a standard CMOS process

This paper describes the design of an ultra-low-power analog front-end circuitry for a UHF passive RFID transponder. The design includes a voltage multiplier, a voltage regulator, a demodulator, a power-on-reset, a ring oscillator, a matching network and a backscatter modulator. We present a novel charge-pump circuit for improved voltage gain and power efficiency of RFID tags. The charge pump is fully integrable and takes advantage of both passive and active multiplication to reduce the required input power. The minimum required input power is ?20.45dBm to generate a 1.2V supply voltage from a 50Ω antenna at 2.4GHz. The voltage multiplier efficiency is 15.95% for a 1MΩ load. The regulator consumes 602nW of DC power and maintains the range of the reference voltage variation to 0.1% while Vdd is varied from 0.8V to 2V. The PSNR of the regulator is -42dB at 2.45GHz frequency and remains greater than -32dB from 100Hz to 10GHz frequencies. The pulse width demodulator is used to extract the input data. The ring oscillator produces a 395 kHz clock for the digital section. Post-layout simulations show the overall power consumption is 1.8μW. The circuit is designed using the low-threshold 0.13μm Atmel CMOS technology. The operating distance of this RFID is in excess of 9 meters based on the regulated 4W EIRP in the US.

Low-power oscillator for passive radio frequency identification transponders

Passive radio frequency identification tags extract energy from incoming electromagnetic waves to power up their internal circuitry. Such a limited source of power demands efficient circuits to minimise the power consumption. In this work a new technique is proposed to design a low-power ring oscillator in which the voltage swing of internal nodes are constrained to lower the dynamic power consumption. The proposed power reduction technique can be employed for RFID tags operating over different frequency bands from low frequency (LF) to microwave. A low-power oscillator operating in the medium-frequency range (6–16 MHz) for applications such as electronic article surveillance and item management has been implemented in this work. Post-layout simulation results using STMicroelectronics CMOS 65 nm technology indicate that the proposed method can reduce the power consumption by more than 25%.

Compact ultrahigh-frequency antenna designs for low-cost passive radio frequency identification transponders

Compact planar antennas for low-cost radio frequency identification (RFID) passive transponders are disclosed. The proposed ultrahigh-frequency antenna takes advantage of its unique topology to assure conjugate matching with essentially complex impedance of the electronic chip directly embedded into the radiator. Rectenna design issues are also emphasised. An original method to characterise IC chips and antennas as taken in its entirety of transponders is presented. The characterisation of the chip takes into account the impact of connecting antennas to the rectifier by flip-chip bonding process. The proposed experimental method allows finding chip impedance exactly as it seen by antennas. Refined rectifier circuitry effectively overcomes dependence of transponder performances on the type deviation of the connected antennas. Very good antenna performance is predicted theoretically and validated experimentally over an operating bandwidth of actual RFID systems.

Ultra-low-power series voltage regulator for passive RFID transponders with subthreshold logic

A series voltage regulator for long-distance passive microwave RFID (RadioFrequency IDentification) transponders, based on subthreshold CMOS circuits, is presented. It is shown that for a voltage regulator that supplies power to subthreshold circuits, temperature compensation would actually represent a disadvantage, while a proper built-in nonzero temperature coefficient can strongly suppress the temperature dependence of the overall subthreshold circuit performance. Implementation and experimental results are discussed.

Design criteria for the RF section of UHF and microwave passive RFID transponders

A set of design criteria for the radio-frequency (RF) section of long-range passive RF identification (RFID) transponders operating in the 2.45-GHz or 868-MHz industrial, scientific, and medical (ISM) frequency ranges is derived in this paper, focusing in particular on the voltage multiplier, the power-matching network, and the backscatter modulation. The paper discusses the design tradeoffs between the error probability at the reader receiver and the converted RF-dc power at the transponder, determining the regions of the design space that allow optimization of the operating range and the data rate of the RFID system.