Semi-passive Radio Frequency Identification Research Articles

Efficiency Measurements of Energy Harvesting from Electromagnetic Environment for Selected General Purpose Telecommunication Systems

The results of measurements of the efficiency of energy harvesting from commonly available general-purpose telecommunications systems, divided into typical bands available under European conditions, have been presented in this paper. Specially designed harvesters were used, dedicated to powering autonomous semi-passive Radio Frequency Identification (RFID) tags. For the assumed resistive loads, the achievable output voltage values of the harvesters were measured across a wide spectrum of electromagnetic field strengths, simulating real conditions. The performance and dynamics of the energy storage process with fixed parameters were studied at an intermediate stage, before the energy conditioning process. The harvesters were treated as typical energy sources with unknown but variable parameters, so their dynamic parameters and instantaneous energy supply were also analyzed. These activities will enable the final development of a power supply system with parameters acceptable for the planned applications and whose efficiency will be maximized under the given conditions. For this purpose, the energy harvesting systems were designed, a suitable laboratory stand was built, and the elaborated circuits were measured to determine the expected parameters of energy harvesting.

Artificial Intelligence-Assisted RFID Tag-Integrated Multi-Sensor for Quality Assessment and Sensing.

Radio frequency identification (RFID) is well known as an identification, track, and trace approach and is considered to be the key physical layer technology for the industrial internet of things (IIoT). However, IIoT systems have to introduce additional complex sensor networks for pervasive monitoring, and there are still challenges related to item-level sensing and data recording. To overcome the shortage, this work proposes an artificial intelligence (AI)-assisted RFID-based multi-sensing technology. Both passive and semi-passive RFID tag-integrated multi-sensors are developed. The main contributions and the novelty of this investigation are as follows. A UHF RFID tag-integrated multi-sensor with a boosted charge pump is proposed; it enables high RF signal sensitivity and a long operational range. The whole hardware design, including the antenna and energy harvester, are studied. Moreover, a demonstration with real-world ham product sensing data is conducted. This work also proposes and successfully demonstrates the integration of machine learning algorithms, specifically the NARX neural network, with RFID sensing data for food product quality assessment and sensing (QAS). This application of machine learning to RFID-generated data for quality assessment is also a novel aspect of the research. The deployment of an autoregressive model with an exogenous input (NARX) neural network model, tailored for nonlinear processes, emerges as the most effective, achieving a root mean square error (RMSE) of 0.007 and an R-squared value of 0.99 for ham product QAS. By deploying the technology, low-cost, timely, and flexible product QAS can be achieved in manufacturing industries, which helps product quality improvement and the optimization of the manufacturing line and supply chain.

Planar Thermoelectric Microgenerators in Application to Power RFID Tags.

This paper presents an innovative approach to the integration of thermoelectric microgenerators (μTEGs) based on thick-film thermopiles of planar constantan-silver (CuNi-Ag) and calcium cobaltite oxide-silver (Ca3Co4O9-Ag) thick-film thermopiles with radio frequency identification (RFID) technology. The goal was to consider using the TEG for an active or semi-passive RFID tag. The proposed implementation would allow the communication distance to be increased or even operated without changing batteries. This article discusses the principles of planar thermoelectric microgenerators (μTEGs), focusing on their ability to convert the temperature difference into electrical energy. The concept of integration with active or semi-passive tags is presented, as well as the results of energy efficiency tests, considering various environmental conditions. On the basis of the measurements, the parameters of thermopiles consisting of more thermocouples were simulated to provide the required voltage and power for cooperation with RFID tags. The conclusions of the research indicate promising prospects for the integration of planar thermoelectric microgenerators with RFID technology, opening the way to more sustainable and efficient monitoring and identification systems. Our work provides the theoretical basis and practical experimental data for the further development and implementation of this innovative technology.

A 22-m Operation Range Semi-Passive UHF RFID Sensor Tag With Flexible Thermoelectric Energy Harvester

This article presents a wireless temperature sensor tag able to work in both fully passive mode and in semi-passive mode when assisted by a flexible thermoelectric generator (TEG). The sensor tag consists of an EPC C1G2/ISO 18000-6C ultrahigh-frequency (UHF) radio frequency identification (RFID) integrated circuit (IC) connected to a low-power microcontroller unit (MCU) that samples and collects the temperature from a digital temperature sensor. With a temperature gradient as low as 2.5 °C, the test results show that the TEG provides an output power of 400 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu$ </tex-math></inline-formula> W with an output voltage of 40mV. Bymeans of an up-converter in order to boost the TEG output voltage, this harvester supplies the power required to the sensor tag for a 2-conv/s data rate in semi-passive mode. Moreover, when the tag operates in semi-passive mode, a communication range of 22.2 m is measured for a 2-W effective radiated power (ERP) reader. To the best of our knowledge, the proposed TEG-assisted sensor tag shows the longest communication range and the only one that provides stable external power at low-temperature gradients. The measured performance and the chosen architecture allow using the wireless sensor in multiple industrial or biomedical applications.

Energy Autonomous Two-Way Repeater System for Non-Line-of-Sight Interrogation in Next Generation Wireless Sensor Networks

In this effort, we present a fully energy autonomous two-way repeater system for use in nonline-of-sight (NLOS) interrogation of wireless sensor networks. The proposed system is based on a pair of tunnel diode reflection amplifiers, taking advantage of the existence of a negative differential resistance region that exists when the device is biased at a low voltage in the quantum tunneling region. This enables the development of an ultralow-cost, ultralow-power means to provide amplification. The proposed system demonstrates an ability to extend the total read range of semipassive radio frequency identification (RFID) tags by 4.55 times while consuming over 1000 times less power than comparable technologies, a notable improvement on previously published work. The system shows an ability to be customized to fit a wide array of different applications where NLOS interrogation and the read range of semipassive RFID tags pose a challenge.

5.8-GHz Low-Power Tunnel-Diode-Based Two-Way Repeater for Non-Line-of-Sight Interrogation of RFIDs and Wireless Sensor Networks

The efficacy of the deployment of backscatter networks in sensor networks and the internet of things has been severely limited by the maximum read range of backscatter radio frequency identification (RFID) tags. The work presented here demonstrates a low-power two-way repeater architecture capable of increasing the read range and extending the coverage of tags to non-line-of-sight (NLOS) scenarios. This is achieved through the use of a two-way frequency divided tunnel diode-based reflection amplifier optimized for use in backscattering channels. The system reports a more than 2X increase in the read range of a semi-passive RFID tag at 17 dBm output power. The work presented here shows a system capable of giving a comparable performance with the state of the art while consuming up to 1000X less power in a simple single-component front end.

A review on wireless sensor technologies

Wireless Sensor Technologies (WST) are entering a new phase. Recent advancements provide enormous possibilities for study and development. This is the result of the lowering costs of ownership, the creation of ever compact sensing devices and the advances in radio frequency technology and digital circuitry. The objective of the current article is to examine the technical and scientific state of the art of wireless sensor technologies and standards for wireless communications in the AgriFood industry. WST in agricultural and food business and to categorize them in suitable categories. These technologies are extremely promising in many areas such as environmental monitoring, precision agriculture, cold chain control or traceability. The article focuses on WSN (Wireless Sensor Networks) and RFID (Radio Frequency Identification), covering the various systems available, current advancements and examples of applications, including ZigBee based WSN and passive, semi-passive and active RFID. Future developments of wireless communications in agricultural and food sector are also addressed.

Designing Antennas for RFID Sensors in Monitoring Parameters of Photovoltaic Panels.

The importance of the radio-frequency identification (RFID) technology and photovoltaic (PV) systems has been growing systematically in the modern world full of intelligent products connected to the Internet. Monitoring parameters of green energy plants is a crucial issue for efficient conversion of solar radiation, and cheap RFID transponders/sensors can be involved in this process to provide better performance of module supervision in scattered installations. Since many components of PV panels disturb the radio-wave propagation, research in the antenna scope has to be carried out to reach the proposed fusion. The problem with RFID transponders being detuned in close proximity to glass or metal surfaces can be solved on the basis of solutions known from the scientific literature. The authors went further, revealing a new antenna construction that can be fabricated straight on a cover glass of the PV panels. To achieve the established task, they incorporated advantages from the latest advancements in materials technology and low-power electronics and from the progress in understanding radio-wave propagation phenomena. The numerical model of the antenna was elaborated in the Hyper Lynx 3D EM software environment, and test samples were fabricated on the technology line of ML System Company. The convergence of calculated and measured antenna parameters confirms the design correctness. Thus, the studied antenna can be used to elaborate the cheap semipassive RFID transponders/sensors in the PV panel production lines.

Guest Editorial: Special Issue on IEEE RFID 2019 Conference

With the proliferation of the Internet of Things, there is an increased demand to enhance every day physical objects with sensors and communication abilities so that they can have digital counterparts (“digital twins”) in a connected world. While many solutions based on protocols such as ZigBee, Bluetooth, ANT, LoRa, LPWAN, NB-IoT, HaLow, etc. do exist, RFID technology presents a compelling alternative. Radio Frequency Identification (RFID) is a generic term for a variety of active and passive RF technologies. RFID transponders have varying degrees of sophistication and their design is often a tradeoff between functionality and cost. At one end of the spectrum, there are active RFID tags that offer on-board battery and memory, sensor integration, active RF transmitters and hence communication range up to kilometers albeit at increased costs. At the other end, passive and semi-passive RFID tags rely on a simple load modulation to backscatter ID and data back to the reader over several meters distance. Passive RFID tags, in particular, lend themselves well for applications needing large-scale, low-cost, automatic identification and are a good option for imparting digital identity to a host of physical assets. Industry alliances such as the NFC forum (for HF RFID) and the RAIN RFID alliance (for UHF RFID) have been formed to motivate and promote these efforts.

Exploiting Switching of Transistors in Digital Electronics for RFID Tag Design

Existing analog-signal side-channels, such as EM emanations, are a consequence of current-flow changes that are dependent on activity inside electronic circuits. In this paper, we introduce a new class of side-channels that is a consequence of impedance changes in switching circuits, and we refer to it as an impedance-based side-channel . One example of such a side-channel is when digital logic activity causes incoming EM signals to be modulated as they are reflected (backscattered), at frequencies that depend on both the incoming EM signal and the circuit activity. This can cause EM interference or leakage of sensitive information, but it can also be leveraged for radio-frequency identification (RFID) tag design. In this paper, we first introduce a new class of side-channels that is a consequence of impedance differences in switching circuits, and we refer to it as an impedance-based side-channel . Then, we demonstrate that the impedance difference between transistor gates in the high-state and in the low-state changes the radar cross section and modulates the backscattered signal. Furthermore, we have investigated the possibility of implementing the proposed RFID on ASIC for signal enhancement. Finally, we propose a digital circuit that can be used as a semi-passive RFID tag. To illustrate the adaptability of the proposed RFID, we have designed a variety of RFID applications across carrier frequencies at 5.8 GHz, 17.46 GHz, and 26.5 GHz to demonstrate the flexible carrier frequency selection and bit configuration.

Long read range Class‐3 UHF RFID system based on harmonic backscattering

A high sensitivity Class-3 ultra high-frequency (UHF) radio-frequency identification (RFID) system based on harmonic backscattering to achieve a long read-range is presented. Harmonic backscattering is a promising solution to solve the carrier leakage issue of UHF RFID reader to improve the sensitivity. In the proposed RFID system based on harmonic backscattering, the RFID reader transmits data with the fundamental frequency carrier and receives data with its second harmonic carrier, and the RFID tag employs a rectifier to generate both DC power and the second harmonic carrier for backscattering without impedance mismatch. The first harmonic Class-3 UHF RFID system based on National Instruments software defined radio platform is proposed and implemented. The proposed semi-passive harmonic RFID tag has dBm sensitivity. Test results show that the harmonic RFID system has a dBm sensitivity with the harmonic RFID tag whose signal-to-blocker ratio is dB at 20 m communication distance.

Embedded Platform for Gas Applications Using Hardware/Software Co-Design and RFID

This paper presents the development of a wireless low power reconfigurable self-calibrated multi-sensing platform for gas sensing applications. The proposed electronic nose (EN) system monitors gas temperatures, concentrations, and mixtures wirelessly using the radio-frequency identification (RFID) technology. The EN takes the form of a set of gas and temperature sensors and multiple pattern recognition algorithms implemented on the Zynq system on chip (SoC) platform. The gas and temperature sensors are integrated on a semi-passive RFID tag to reduce the consumed power. Various gas sensors are tested, including an in-house fabricated $4\times 4$ SnO 2based sensor and seven commercial Figaro sensors. The data is transmitted to the Zynq based processing unit using a RFID reader, where it is processed using multiple pattern recognition algorithms for dimensionality reduction and classification. Multiple algorithms are explored for optimum performance, including principal component analysis (PCA) and linear discriminant analysis (LDA) for dimensionality reduction while decision tree (DT) and k-nearest neighbors (KNN) are assessed for classification purpose. Different gases are targeted at diverse concentration, including carbon monoxide ( CO ), ethanol ( C 2 H 6 O ), carbon dioxide ( CO 2), propane ( C 3 H 8), ammonia ( NH 3), and hydrogen ( H 2). An accuracy of 100% is achieved in many cases with an overall accuracy above 90% in most scenarios. Finally, the hardware/software heterogeneous solution to implementation PCA, LDA, DT, and KNN on the Zynq SoC shows promising results in terms of resources usage, power consumption, and processing time.

Diversity Study of a Frequency Selective Surface Transponder for Wearable Applications

This communication presents a semipassive radio frequency identification system in the 2.45-GHz Industrial, Scientific and Medical band. The transponder (or tag) is based on a modulated frequency selective surface (FSS). The FSS is composed of dipoles loaded with varactor diodes that modulate the radar cross section. The FSS transponder is designed to work for wearable and on-body applications and is used for reading and transmitting information from different sensors placed on the body. Experimental results locating the FSS at different positions in real scenarios and also at different places on the body are provided. Multiple FSSs have been used to explore spatial and polarization diversity techniques in order to mitigate the deep fadings that can happen during communication. Noticeable diversity gain has been obtained in both the cases without using antenna diversity in the reader. Finally, this communication describes a proof-of-concept experiment of the communication where two FSSs send digital data using a frequency shift keying modulation.

Measurement System With Accelerometer Integrated RFID Tag for Infrastructure Health Monitoring

This paper presents a measurement system for measuring dynamic acceleration of infrastructure remotely using semipassive radio-frequency identification (RFID) tag. This measurement is critical to the vibration-based method for infrastructure health monitoring. Design considerations of accelerometer integrated ultrahigh-frequency RFID tag and dynamic acceleration measurements through an RFID wireless link are discussed. Measurement results of the system for a structural specimen have shown that it is capable of acquiring data which provides the information of natural frequency of the structural specimen. Moreover, the system can distinctively identify the state changes of the structural specimen by natural frequency shifts. These results are benchmarked against the results obtained with two commercial systems. It is shown that the standard deviation of the measurement of the natural frequency is ±0.01 Hz which is very close to the standard deviation of the commercial measurement systems.

Reducing the phase cancellation effect in augmented RFID system

This paper proposes to use the spatial diversity of dual-antenna to counter the phase cancellation effect in an augmented radio frequency identification (RFID) system, which is developed for accurate indoor localization. In the augmented RFID system, a tag-like semi-passive RFID component (referred as sensatag) senses the backscattering communication between standard ISO 18000-6C compliant RFID reader and passive tags within its proximity. However, due to the superposition of reader's carrier wave (CW), the amplitude difference in the tag's backscattering signal is significantly attenuated at the sensatag's antenna. We refer to such effect as phase cancellation. To counter the destructive phase cancellation effect, two techniques are proposed based on dual-antenna diversity. In the first one called simple combination technique, simple addition of signals from two antennas is performed; in the second one called receiving path selection technique, signals from both antennas are converted into baseband and then conduct the selection in digital domain. Then we demonstrate the performance of these two techniques in a newly developed Proximity-detection-based augmented RFID system simulator (PASS) framework. The result shows that dual-antenna-based implementations are better than the simple antenna implementation in reducing phase cancellation effect. Moreover, receiving path selection technique reduces the probability of phase cancellation significantly with higher hardware complexity compared with simple combination technique.

Reducing Phase Cancellation Effect with ASK-PSK Modulated Stamp in Augmented UHF RFID Indoor Localization System

Abstract In this paper, we propose exploiting ASK-PSK modulated stamp in receiving path selection technique to lessen the phase cancellation effect in augmented ultra-high-frequency (UHF) radio frequency identification (RFID) indoor localization system (AURIS). In AURIS, a tag-like semi-passive RFID component (referred as sensatag) can capture backscatter signal of other proximal tags with presence of RF source. According to the principle of backscatter radio link, the received signal at sensatag antenna is the superposition of backscatter signal of tags and continuous carrier wave (CW) from RF source. However, due to phase difference between tag's backscatter signal and RF CW, the modulated backscatter signal could be cancelled. We refer this effect as phase cancellation effect. Exploiting the spatial diversity of dual-antenna's two receiving paths, the likelihood of phase cancellation occurrence could be reduced. But the developed technique with two co-operating paths is not energy efficient. Therefore, this paper proposes to inject a ASK-PSK modulated stamp sequence in the pilot tone of backscatter signal as a signature of phase cancellation for ASK modulated data frame, which could be identified by the receiving sensatag. With the knowledge of occurrence of phase cancellation, sensatag could activate the alternative receiving path. This technique fully exploits the space diversity of dual-antenna, and also reduces the power consumption by reducing one receiving path in operation. We demonstrate the performance of stamp based receiving path selection technique with data obtained from computer simulation.

Design and Development of Sensing RFID Tags on Flexible Foil Compatible With EPC Gen 2

Taking advantage of the sensor interface capabilities of a radio frequency identification (RFID) chip, the integration of different types of sensors on printed ultrahigh frequency (UHF) RFID tags is investigated. The design, development, and testing of printed smart sensing tags compatible with the RFID standard electronic product code Gen 2 is presented. Two different strategies are employed to interface the sensors: 1) passive single-chip and 2) semipassive architectures. Both strategies provide sensor data by directly answering to the RFID reader inquiries or using a data logging mechanism to store the sensor data in the RFID chip memory. Temperature readout is measured using the embedded sensor in the RFID chip. Additionally, a light sensor and pressure sensor interfaced to a microcontroller are implemented in the passive and semipassive tags versions, respectively. For the employed RFID chip, two different UHF antennas are designed and printed using inkjet and screen printing to compare their radio frequency performances. Finally, the fabricated smart tags are fully validated through measurements in an anechoic chamber and their behaviors are compared with numerical simulation. The screen printed semipassive RFID tag with loop antenna shows a better reading range than the inkjet-printed one, whereas the passive tag can be considered as the most cost-effective system.

Oxygen plasma treated carbon nanotubes for the wireless monitoring of nitrogen dioxide levels

There is a growing interest in the development of smart global systems of wireless, distributed sensors that can be deployed and then operated with no human intervention. However, there are still important technological barriers related to sensor performance and power consumption that limit the implementation of such systems. This paper shows that nanotechnology could help overcome these barriers. An oxygen plasma treatment has been used to functionalise, in a controlled way, the outer walls of multiwalled carbon nanotubes. This treatment respects the integrity of carbon nanotubes but gives rise to carbonyl groups grafted at their sidewalls, which greatly enhance the room-temperature sensitivity and selectivity of the nanomaterial to nitrogen dioxide. The detection mechanism of nitrogen dioxide in the presence of ambient moisture is discussed in light of computational modelling, compositional characterisation and gas sensing tests. The optimised nanomaterial has been used to develop a semi-passive radio frequency identification tag with the capability of sensing nitrogen dioxide in the environment. The tag, which is read by a low-cost commercially available ultra-wideband radar, is normally in sleep mode and includes a wake-up circuit, so power consumption is minimised. This wireless sensor is able to reproducibly detect nitrogen dioxide concentrations from 10ppm to 100ppm, with a mean relative error of 0.29%.

Properties and Printability of Inkjet and Screen-Printed Silver Patterns for RFID Antennas

We report the modeling, and geometrical and electrical characterization, of inkjet and screen-printed patterns on different polymeric substrates for use as antennas in radio-frequency identification (RFID) applications. We compared the physical and electrical characteristics of two silver nanoparticle-based commercial inkjet-printable inks and one screen-printable silver paste, when deposited on polyimide (PI), polyethylene terephthalate (PET), and polyetherimide (PEI) substrates. First, the thickness of the inkjet-printed patterns was predicted by use of an analytical model based on printing conditions and ink composition. The predicted thickness was confirmed experimentally, and geometrical characterization of the lines was completed by measuring the root-mean-square roughness of the patterns. Second, direct-current electrical characterization was performed to identify the printing conditions yielding the lowest resistivity and sheet resistance. The minimum resistivity for the inkjet-printing method was 8.6 ± 0.8 μΩ cm, obtained by printing four stacked layers of one of the commercial inks on PEI, whereas minimum resistivity of 44 ± 7 μΩ cm and 39 ± 4 μΩ cm were obtained for a single layer of screen-printed ink on polyimide (PI) with 140 threads/cm mesh and 90 threads/cm mesh, respectively. In every case, these minimum values of resistivity were obtained for the largest tested thickness. Coplanar waveguide transmission lines were then designed and characterized to analyze the radio-frequency (RF) performance of the printed patterns; minimum transmission losses of 0.0022 ± 0.0012 dB/mm and 0.0016 ± 0.0012 dB/mm measured at 13.56 MHz, in the high-frequency (HF) band, were achieved by inkjet printing on PEI and screen printing on PI, respectively. At 868 MHz, in the ultra-high-frequency band, the minimum values of transmission loss were 0.0130 ± 0.0014 dB/mm for inkjet printing on PEI and 0.0100 ± 0.0014 dB/mm for screen printing on PI. Although the resistivity achieved is lower for inkjet printing than for screen printing, RF losses for inkjetted patterns were larger than for screen-printed patterns, because thicker layers were obtained by screen printing. Finally, several coil inductors for the HF band were also fabricated by use of both printing techniques, and were used as antennas for semi-passive smart RFID tags on plastic foil capable of measuring temperature and humidity.

Feasibility of backscatter RFID systems on the human body

In this contribution, the author examines the feasibility of on-body backscatter radio frequency identification (RFID) systems in the ultra high frequency range. Four different on-body RFID systems are investigated operating monopoles or patch antennas at 900 MHz or 2.45 GHz. The systems’ feasibility is analyzed by means of on-body channel measurements in a realistic test environment. The measured channel transfer functions allow to evaluate if enough power is available for a reliable backscatter communication. This evaluation is done with the aid of outage probabilities in the forward link and the backward link of the systems. Using these probabilities, the on-body systems prove feasible when using state-of-the-art reader and transponder chips. In particular, the use of semi-passive RFID transponder chips leads to a reliable performance in the systems’ forward links. The robust performance of the systems’ backward links is clearly shown for the 900 MHz monopole antenna configuration, while the limitations in the backward links of the other systems have to be overcome by the use of a second reader unit on the person’s back. The novel feasibility analysis presented here allows to examine each system parameter individually and thus leads to reliable and robust backscatter RFID systems.