Radio Frequency Identification Sensor Tag Research Articles

A Feasibility Study on Monitoring Earthquake-Caused Furniture Vibrations Using Radiofrequency Identification Sensor Tags

This paper presents a feasibility study on monitoring earthquake-caused furniture vibrations using radiofrequency identification (RFID) sensor tags. Finding unstable objects by exploiting the vibrations caused by weaker earthquakes is effective as one of the potential countermeasures for large-scale earthquakes in earthquake-prone areas. For this purpose, a previously proposed ultrahigh-frequency (UHF)-band RFID-based batteryless vibration/physical shock sensing system enabled long-term monitoring. This RFID sensor system introduced standby and active modes for long-term monitoring. This system enabled lower-cost wireless vibration measurements without affecting the vibration of furniture because the RFID-based sensor tags provide lightweight, low-cost, and battery-free operations. This RFID sensor system observed earthquake-cased furniture vibrations in a room on the fourth floor of a building eight stories high at Ibaraki University, Hitachi, Ibaraki, Japan. The observation results revealed that the RFID sensor tags identified the vibrations of furniture caused by earthquakes. The RFID sensor system also observed the vibration duration times of the objects in a room and specified the most unstable reference object. Hence, the proposed vibration sensing system helped achieve safe living in indoor environments.

Design of a metamaterial chipless RFID sensor tag for high temperature

A high temperature sensor based on a metamaterial is proposed as a chipless radio frequency identification sensor tag that can measure temperature wirelessly. The metamaterial, based on a double circular split ring resonator (SRR), is highly frequency selective and has negative permittivity. The double circular SRR is fabricated on the alumina ceramic substrate, which acted as the temperature sensing material. The permittivity of the material varies with the temperature parameter, resulting in a shift of backscattered resonant frequency of the sensor tag. Simulations verify the feasibility of this sensor tag in the microwave band under electromagnetic stimuli. When the temperature increases from 200 to 1000 °C, the resonant frequency monotone decreases from 6.64 to 6.26 GHz with an average sensitivity of 0.475 MHz/°C. The sensor tag has features such as high temperature, being wireless, passive, of comparatively low-cost, and miniature, with diversified application potential, allowing it to compete with other sophisticated temperature devices in terms of performance.

A Novel Multiresonant Chipless RFID Tag for Directional Strain Measurement on Metal Surface

In this article, a radio frequency identification (RFID) sensor tag for real-time health monitoring of the magnitude and direction of metal surface strain is presented. The chipless RFID sensor tag is composed of metal foil and F4B substrate, which is low-cost and works stably in harsh environments for a long time. Through highly sensitive strain monitoring, the risk can be predicted in the early stage of defect generation. The proposed tag includes a C-type resonator array, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> -type transmission line, and tag antennas. The C-type resonator has different sensitivities in the electrical length direction and width direction. Then, based on this characteristic, the resonator array creates a plurality of characteristic signatures containing strain information by optimizing the geometric parameters of the resonators. The strain information is transmitted to the tag antenna through the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> -type transmission line to complete the wireless communication between the tag and the reader. Finally, the performance of the strain monitoring system is verified by an experimental study. The experiment shows that the average sensitivity of the resonators is −4.94 and 1.14 kHz/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \varepsilon $ </tex-math></inline-formula> in the electric length and width directions, respectively. When the strain is more than 150 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \varepsilon $ </tex-math></inline-formula> , the relative error of magnitude is less than 12.7% and the absolute error of direction is less than 13.3°. Therefore, the proposed chipless RFID tag can monitor the amplitude and direction of strain with higher sensitivity and a simpler structure, for the key structures, such as the high-speed running gear.

Radio Frequency Identification Temperature/CO2 Sensor Using Carbon Nanotubes

In the world of digitization, different objects cooperate with the Internet of Things (IoT); these objects also amplify using sensing and data processing structures. Radio frequency identification (RFID) has been identified as a key enabler technology for IoT. RFID technology has been used in different conventional applications for security, goods storage, transportation and asset management. In this paper, a fully inkjet-printed chipless radio frequency identification (RFID) sensor tag is presented for the wireless identification of tagged objects. The dual polarized tag consists of two resonating structures functioning wirelessly. One resonator works for encoding purpose and other resonator is used as a CO2/temperature sensor. The sensing behavior of the tag relies on the integration of a meandered structure comprising of multi-wall carbon nanotubes (MWCNT). The MWCNT is highly sensitive to CO2 gas. The backscattered response of the square-shaped cascaded split ring resonators (SRR) is analyzed through a radar cross-section (RCS) curve. The overall tag dimension is 42.1 mm × 19.5 mm. The sensing performance of the tag is examined and optimized for two different flexible substrates, i.e., PET and Kapton®HN. The flexible tag structure has the capability to transmit 5-bit data in the frequency bands of 2.36-3.9 GHz and 2.37-3.89 GHz, for PET and Kapton®HN, respectively. The proposed chipless RFID sensor tag does not require any microchip or a power source, so it has a great potential for low-cost and automated temperature/CO2 sensing applications.

An RFID-Based Wireless Vibration and Physical-Shock Sensing System Using Edge Processing

This article presents energy-efficient edge processing for an ultrahigh-frequency (UHF) band radio-frequency identification (RFID)-based vibration frequency/ physical shock sensing system. This system is especially useful for long-term measurements. In this edge processing system, an RFID reader has a standby mode operating at a low duty cycle and an active mode operating at a high duty cycle. With these modes, an RFID reader achieves both energy-efficient operations and accurate sensing performance. The standby mode is useful for reducing energy consumption, preventing overheating, and reducing greenhouse gas emissions because a low duty cycle leads to a short radio wave irradiation time. Reducing the heat generation of the RFID reader, especially for long-term measurements, the standby mode makes the RFID reader durable. If vibration/physical shocks are applied to the RFID sensor tag, then the standby mode triggers the active mode. The standby mode samples the presence of the RFID sensor tags within an experimentally determined sampling period to detect the beginning of vibration/physical shocks. A high-duty cycle in the active mode results in an increased number of RFID sensor tag readings. Because the proposed edge processing keeps measured data only for the active mode, the amount of data uploaded to the Internet-of-Things (IoT) cloud is reduced. The proposed method was experimentally evaluated by monitoring walking behaviors and a refrigerator. The vibration sensing capability was mainly validated by monitoring a refrigerator, and the physical shock sensing capability was evaluated by monitoring walking behaviors by a human examinee.

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.

Metamaterial-enhanced near-field readout platform for passive microsensor tags

Radiofrequency identification (RFID), particularly passive RFID, is extensively employed in industrial applications to track and trace products, assets, and material flows. The ongoing trend toward increasingly miniaturized RFID sensor tags is likely to continue as technology advances, although miniaturization presents a challenge with regard to the communication coverage area. Recently, efforts in applying metamaterials in RFID technology to increase power transfer efficiency through their unique capacity for electromagnetic wave manipulation have been reported. In particular, metamaterials are being increasingly applied in far-field RFID system applications. Here, we report the development of a magnetic metamaterial and local field enhancement package enabling a marked boost in near-field magnetic strength, ultimately yielding a dramatic increase in the power transfer efficiency between reader and tag antennas. The application of the proposed magnetic metamaterial and local field enhancement package to near-field RFID technology, by offering high power transfer efficiency and a larger communication coverage area, yields new opportunities in the rapidly emerging Internet of Things (IoT) era.

Intermittent Magnetic Field Monitoring System Based on Passive RFID Sensor Tags

The monitoring of magnetic fields is extremely important in many industrial environments, e.g., power grids. Despite of its importance, the existing monitoring methods either are large in size, require high power consumptions and manual observation, or although integrated in small wireless devices, need the use of batteries, increasing maintenance costs. This paper proposes an intermittent magnetic field monitoring system based on passive ultra-high frequency (UHF) radio frequency identification (RFID) technology. A magnetic field magnitude sensor has been integrated into a micro-controller unit (MCU) based tag, and the standard RFID communication protocol ISO/IEC 18000-6 Type C has been partially modified to allow faster sensed data transfer, especially for multiple tag situations rarely considered in the open literature. Static or 50 Hz magnetic field sensing accuracy lower than 3% have been experimentally measured with reasonable tag charging times and read distances, making possible for example to monitor magnetic fields on more than 10 locations simultaneously with a 60 s of updating time with a tag read range of 3 m.

Electrical gas sensors for meat freshness assessment and quality monitoring: A review

The simple methods for Freshness assessment have been gained attention in the last years, mainly in case of highly perishable food products as those delivered by the meat sector . Furthermore, the growing demand for fresh and safe food makes the development of reliable, low-cost and time-saving methods for freshness investigation an important need. In this context, gas sensors represent a valuable tool to food freshness and quality monitoring , avoiding the supply and consumption of rotten meat products, which may be associated with foodborne diseases. The present work gives an overview of the existing gas sensors applied to meat quality monitoring, with emphasis on a particular class of gas sensors, the electrical gas sensors . This type of sensors has been shown to have a promissory interface with wireless technologies, such as the existing NFC (near field communication) and RFID (radio frequency identification) sensor tags, which may lead to meat quality and safety assurance at consumers’ level. The presented literature studies demonstrated that the electrical properties of different materials have been exploited for the development of gas sensors. The implementation of electrical gas sensors interfaced with wireless is a promising technology in the near future because of the possibility of a rapid and accessible meat quality monitoring. • Recent gas sensors applications and prospects for meat quality are reviewed. • Gas sensors for meat monitoring were summarized based on the transduction principle. • Electrical gas sensor (EGS) versatility in meat quality and freshness assessment. • EGS combined with wireless technologies has great potential for meat monitoring.

Flexible RFID Tag for Sensing the Total Minerals in Drinking Water via Smartphone Tapping

The recent advances in energy-efficient electronics and sensor fabrication techniques have reshaped the way of sensing and communication, which have nurtured many novel applications. Among the emerging sensing techniques, wirelessly powered sensing and communication enhanced by Radio Frequency Identification (RFID) has gained increasing popularity. In this investigation, we propose a novel flexible RFID sensor tag powered and interrogated by a smartphone with its in-built High-Frequency (HF) RFID module, which can be applied for convenient non-contact analysis of liquids. In this work, the evaluation of total minerals in drinking water is conducted as a proof-of-concept demonstration. The main contributions include: (1) modeling and theoretical analysis of a planar capacitive sensor for liquids analysis by sensing the dielectric properties; (2) design of a flexible capacitive sensor tag that can be conformally mounted on the sidewall of containers for the liquid analysis; (3) a power-efficient hardware scheme for HF RFID powered battery-less sensing via smartphone tapping; (4) a Near Field Communication (NFC) data transmission method for convenient measurement without added software in smartphone devices. Finally, the developed sensor tag is calibrated by multi-piece linear function fitting. Experimental results and quantitative analysis demonstrate the feasibility of the proposed methodology.

Design of UHF RFID Sensor-Tags for the Biomechanical Analysis of Human Body Movements

This paper presents the design and the development of a Battery Assisted Passive Radio-Frequency IDentification (RFID) tag in the Ultra High-Frequency band integrated with inertial measurement unit (IMU) sensors tested for the biomechanical analysis of human body movements. Enhanced by a compact and efficient meandered Planar Inverted-F Antenna (PIFA), the device exploits a specific RFID chip having a dual-access -wired and wireless- to the memory. A properly decoupled cell battery is also foreseen to boost the chip sensitivity and to supply power to an ultra-low power microcontroller and to the sensors. The device has been realized using off-the-shelf low-cost discrete components on FR4 substrate, validated, and tested in capturing real human movements. Two sensor-tags have been applied on the pelvis and on the torso of an individual moving in front of the RFID Reader antenna. Afterward, sensor data have been collected, processed, and filtered with specific algorithms, and used to control a musculoskeletal virtual model in the OpenSense software tool. The results show that the whole system correctly reproduces the performed movements, demonstrating the appropriateness of the proposed RFID-sensor in wireless movement capture applications.

Printed, flexible, compact UHF-RFID sensor tags enabled by hybrid electronics

Sensor data can be wirelessly transmitted from simple, battery-less tags using Radio Frequency Identification (RFID). RFID sensor tags consist of an antenna, a radio frequency integrated circuit chip (RFIC), and at least one sensor. An ideal tag can communicate over a long distance and be seamlessly integrated onto everyday objects. However, miniaturized antenna designs often have lower performance. Here we demonstrate compact, flexible sensor tags with read range comparable to that of conventional rigid tags. We compare fabrication techniques for flexible antennas and demonstrate that screen and stencil printing are both suitable for fabricating antennas; these different techniques are most useful at different points in the design cycle. We characterize two versions of flexible, screen printed folded dipoles and a meandered monopole operating in the 915 MHz band. Finally, we use these antennas to create passive sensor tags and demonstrate over the air communication of sensor data. These tags could be used to form a network of printed, flexible, passive, interactive sensor tags.

A Flipping UHF RFID Sensor-Tag for Metallic Environment Compliant With ETSI/FCC Bands

A novel dual-band ultrahigh-frequency (UHF) radio frequency identification (RFID) sensor tag, designed to operate on metallic surfaces, is proposed. This particular UHF RFID sensor tag is capable of operating in both the main RFID frequency bands of the European Telecommunications Standards Institute (ETSI) and the Federal Communication Commission (FCC). The dual-band operation of the UHF RFID sensor tag is based on a very simple concept; by flipping the UHF RFID sensor tag on a metallic surface, it can operate either in the ETSI or FCC RFID frequency bands. The impedance and radiation characteristics of the UHF RFID sensor tag are presented with an extensive analysis of the effects of the metallic surface on the UHF RFID sensor tag. In addition, an equivalent model of the UHF RFID sensor tag, which includes the effects of the metallic surface on the sensor tag, is proposed. The UHF RFID sensor tag has a small form factor and presents a satisfying read range of around 3 m for both the operating frequency bands in a metallic environment as well as a read range of 1.4 m when operating in free space.

External Breaking Vibration Identification Method of Transmission Line Tower Based on Solar-Powered RFID Sensor and CNN

This paper proposes an external breaking vibration identification method of transmission line tower based on a radio frequency identification (RFID) sensor and deep learning. The RFID sensor is designed to obtain the vibration signal of the transmission line tower. In order to achieve long-time monitoring and longer working distance, the proposed RFID sensor tag employs a photovoltaic cell combined with a super capacitor as the power management module. convolution neural network (CNN) is adopted to extract the characteristics of vibration signals and relevance vector machine (RVM) is then employed to achieve vibration pattern identification. Furthermore, the Softmax classifier and gradient descent method are used to adjust the weights and thresholds of CNN, so as to obtain a high-precision identification structure. The experiment results show that the minimum sensitivity of the proposed solar-powered RFID sensor tag is −29 dBm and the discharge duration of the super capacitor is 63.35 h when the query frequencies are 5/min. The optimum batch size of CNN is 5, and the optimum number of convolution cores in the first layer and the second layer are 2 and 4, respectively. The maximum number of iterations is 10 times. The vibration identification accuracy of the proposed method is over 99% under three different conditions.

Optically Transparent 24 GHz Analog Front-End Based on Meshed Microstrip Lines for the Integration in a Self-Sufficient RFID Sensor Tag

This paper presents a 24 GHz Radio Frequency IDentification (RFID) sensor tag including an optically transparent patch antenna and an RF circuit. These components are placed on a single efficient solar cell and the transparency is achieved by realizing metal patches and lines as grid structure. Since the analog front-end is implemented in the microstrip line technology, the impact of the grid structure on the characteristic impedance and the propagation constant of microstrip transmission lines is studied in detail. The knowledge derived are taken into account in the design process of the meshed patch antenna as well as the modulator and demodulator circuit. Furthermore, the influence of the solar cell on the characteristics of the analog front-end is investigated. The overall dimensions of the sensor tag are $13\times 13\times 4$ mm3 including the aforementioned components, a microcontroller, an acceleration sensor and an energy storage. The perforated analog front-end fabricated on quartz glass has an overall transparency of 75 % and an antenna efficiency of 49 %. The achieved sensitivity value of the developed RFID sensor tag is −36 dBm resulting in a maximum communication range of approximately 1.3 m.

Localization of Signal Pattern Based UHF RFID Sensor Tags

This letter presents a prototype system that combines sensing and localization capabilities based on the radio frequency identification (RFID) technology in the ultrahigh-frequency (UHF) band. The system detects empty water tanks by recognizing a predefined transponder (tag) signal pattern at the reader. The shape of this pattern is determined by a custom-built sensor tag antenna that interacts in a unique way with an off-the-shelf microchip and the water filling level. The localization of this sensor tag is achieved by a 2-D direction of arrival (DoA) estimation, exploiting a $2\times2$ antenna array. The measurement results compare well with electromagnetic simulations. It is shown that the detection of the sensing state is sufficiently robust to cope with different tank positions, even in multipath environments. Furthermore, the system is robust in its localization performance, although the sensing state influences the wireless channel.

Radio Frequency Identification and Sensing Techniques and Their Applications-A Review of the State-of-the-Art.

Radio Frequency Identification (RFID) sensors, integrating the features of Wireless Information and Power Transfer (WIPT), object identification and energy efficient sensing capabilities, have been considered a new paradigm of sensing and communication for the futuristic information systems. RFID sensor tags featuring contactless sensing, wireless information transfer, wireless powered, light weight, non-line-of-sight transmission, flexible and pasteable are a critical enabling technology for future Internet-of-Things (IoT) applications, such as manufacturing, logistics, healthcare, agriculture and food. They have attracted numerous research efforts due to their innovative potential in the various application fields. However, there has been a gap between the in-lab investigations and the practical IoT application scenarios, which has motivated this survey of this research to identify the promising enabling techniques and the underlying challenges. This study aims to provide an exhaustive review on the state-of-art RFID sensor technologies from the system implementation perspective by focusing on the fundamental RF energy harvesting theories, the recent technical progresses and commercial solutions, innovative applications and some RFID sensor based IoT solutions, identify the underlying technological challenges at the time being, and give the future research trends and promising application fields in the rich sensing applications of the forthcoming IoT era.

Transformer Fault Diagnosis Method Based on Self-Powered RFID Sensor Tag, DBN, and MKSVM

A novel transformer fault diagnosis method using self-powered radio frequency identification (RFID) sensor tag, deep belief network (DBN), and multiple kernel support vector machine (MKSVM) is presented. The self-powered RFID sensor tag is applied to measure transformer vibration signals, which has advantages of convenience, long-term monitoring, low power consumption, and fast location. Then, the DBN is employed to extract features from the measured signals, and the DBN method’s extraction performance is improved by optimizing its learning rates and momentum factors. The extracted features of the same fault are highly centralized, and the features of the different faults are obviously separated. Based on the features, the MKSVM is utilized to construct a transformer fault diagnosis model, and the MKSVM’s penalty factor and kernel weights are optimized through a quantum-behaved particle swarm optimization (QPSO) algorithm. Finally, a mean signal deviation (MSD) metric is presented to locate the fault position. In this experiment, a 10 kV transformer is used to demonstrate the proposed transformer fault diagnosis procedure, and the diagnosis results reflect that the proposed method can effectively measure the transformer vibration signals, extract the essential features, construct an accurate diagnosis model, and locate the fault position.

Multiresonance Chipless RFID Sensor Tag for Metal Defect Characterization Using Principal Component Analysis

One of the challenges in structural health monitoring (SHM) is that defects, such as metal cracks and corrosions, can occur with multiple material properties and multilayer structure, entangled with influences from the reader system and the environment. This paper presents a multiresonance chipless radio frequency identification (RFID) sensor tag and the chipless RFID sensor reader applying principal component analysis (PCA) for multiparameter estimation in metal defect characterization. The proposed sensor tag is composed of the crossed diagonal dipole patches and the L-shaped patches generating six resonance peaks within 2-6-GHz band. The frequency signature of the sensor tag is acquired and processed by a chipless RFID reader implemented using an ultra-wideband impulse radar (UWB-IR) transceiver module. We demonstrate that the multiresonance chipless RFID sensor tag in conjunction with PCA-based feature extraction and selection can be applied for the characterization of metal crack with different widths and orientations. Furthermore, the proposed technique can find a robust feature indicating corrosion stages under a coating layer regardless of the sample orientation. This paper paves the way for multiparameter defect sensing and monitoring using a chipless RFID sensor system.

Self-Tuning RFID Tag: A New Approach for Temperature Sensing

This paper aims to present a further exploration on a new concept regarding the operation of an ultrahigh frequency (UHF) radio frequency identification (RFID) sensor tag. Exploiting the antenna of a UHF RFID tag as a temperature transducer and a UHF RFID chip with self-tuning capabilities as the means of communication, a UHF RFID tag can operate as a very low-power sensor with high read range and small size. The antenna of the tag is taking advantage of the intrinsic characteristics of the used substrate to vary its overall complex impedance according to temperature. These changes of the impedance of the antenna are leading the self-tuning circuit of the used RFID chip to self-tune and based on the value it acquires an estimation of the sensed temperature can be made. This paper also reports a design and a set of measurements of a UHF RFID tag transformed to act as a temperature sensor. This concept is further explored for the assessment of the contribution of each of the constituents of the UHF RFID tag, i.e., antenna and UHF RFID chip, to the sensing procedure. This paper is accompanied by the simulation of a designed 3-D model of the UHF RFID sensor tag and by sets of measurement of the impedances of the UHF RFID chip and of the antenna.