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A novel broadband ultra‐high frequency radio frequency identification (RFID) tag antenna attached to the metallic surface is proposed in this paper. A rectangular wide slot combined with a U‐shaped thin slot outside is adopted in the proposed antenna, and the size of the patch can be reduced by adjusting the length of the U‐shaped slot. Furthermore, a pair of symmetric resonator structures inside the rectangular slot are connected to both ends of the chip, which can excite a new resonant mode to broaden the frequency band. All the structures above are realized by etching rectangular slits on the same surface. The antenna has the advantages of wideband, simple processing, and good reading distance, and the 10 dB bandwidth of the antenna is 30 MHz (from 895 to 925 MHz), with a maximum directional gain of −3.5 dB. The reading distance can reach more than 5.4 m on a metallic surface. [ABSTRACT FROM AUTHOR]

Radio Frequency Identification (RFID) technology is one of the simplest forms of wireless communication systems. It is a unique concept that aims at connecting and identifying tagged assets or objects to RFID readers to collect information. This paper presents the design and implementation of a compact dual-band monopole antenna for RFID applications. The proposed design is a microstrip antenna structure composed of two coupled armed meander-lines having 90° between them to achieve circular polarization. The proposed design is mounted on a 1.6mm thick FR4-epoxy substrate backed by a partial ground plane with the total area of (58 x 80mm²) to ensure compact size of the design. The designed antenna is fed through a 50-ohm transmission line of length 28.5 mm. The antenna is considered dual bands that resonate at 850MHz and 1.5 GHz and radiates circularly polarized waves with an axial ratio of 1.4. The simulation results using HFSS software showed promising performance with a bandwidth of 141MHz at centre frequency 850MHz and 287MHz at centre frequency 1.5 GHz, respectively. The S11 parameter shows return loss of -21 dB at 850MHz band while at the higher frequency band the return loss is much better which was -39 dB. The design provides a perfectly omnidirectional radiation pattern and high radiation efficiency of 93%. Fabrication of the proposed design is done with practical results having a similar trend to the simulated ones to convey good performance of the designed antenna. [ABSTRACT FROM AUTHOR]

In this article, a novel ultra-high frequency radio frequency identification (UHF RFID) reader antenna is proposed and experimentally investigated. The proposed RFID antenna design consists of three layers; the first layer has a ring shape with a feeding line at the center, the second layer has a small periodic structure that affects the radiation performance of the antenna, and the third layer has a bent metal structure. The final design, with the dimensions of 129.2 mm × 129.2 mm × 26 mm, yields a 10-dB impedance bandwidth of 34 MHz (854–889 MHz) and a 3-dB axial-ratio bandwidth of 118 MHz (857–975 MHz). The antenna is fabricated and tested for its RF parameters and RFID metrics. In performance tests, ISO 18000–63 and Gen2v2 compatible RFID reader and tags are used. RFID tag reading tests have been successfully performed under specified communication protocols without any operational failure while providing RF communication. The measured results prove the technical potential of the proposed antenna to possess good RF performance in RFID based wireless networks. [ABSTRACT FROM AUTHOR]

A compact tag antenna, which has a geometrical dimension of 31.5 mm $\times31.5$ mm $\times3.2$ mm, is constructed using a stacked planar inverted-L antenna (PILA) for metal-mountable applications in the UHF radio frequency identification (RFID) passband. The new antenna is formed by inserting a shorted patch into a PILA structure to create a double-layered inverted antenna, which can be viewed as a cascade of two parallel resonant tanks. An increase in electric field intensity in the antenna structure has brought in sufficient capacitance for reducing the tag resonant frequency effectively to the useful UHF RFID passband. Due to the increase in the antenna reactance, conjugate impedance matching can be easily achieved between the antenna and the microchip. Fine-tuning schemes such as stubs and slits are also incorporated with the proposed tag antenna for adjusting the operating frequency to an exact precision. Measurements show that the proposed tag antenna can achieve a read distance of 7.25 m at an EIRP power of 4 W. The resonance of the proposed tag antenna is found to be very stable and it is insensitive to changes in the backing metal platform. [ABSTRACT FROM AUTHOR]

For the first time, the ionic polymer metal composite (IPMC) actuator is integrated with a radio frequency identification (RFID) tag antenna for achieving frequency reconfiguration in the ultrahigh-frequency (UHF) band. Here, the IPMC movable flap serves as an actuator that can effectively tune the tag resonant frequency. By applying a two-layer-crenelated structure and employing a surface patterned electrode for restraining back relaxation, the deflection of the IPMC actuator can be significantly improved. The IPMC actuator can move in two directions, enabling two-degree frequency tuning. Numerical and experimental data confirm that the tip displacement of the IPMC actuator can be enhanced up to 266% with the use of the two-layer-crenelated structure. The IPMC actuator allows the resonant frequency of the tag antenna to be tuned back by as much as 35 MHz, after deviating due to placing on an unintended object. UHF RFID application is also performed using a portable commercial RFID reader. Good frequency reconfiguration and broad tuning range, along with far read distances, have been achieved with our tunable UHF RFID tag antenna. [ABSTRACT FROM AUTHOR]

In this paper, we present a new antenna for radio frequency identification (RFID) tag operating in the Moroccan ultra high frequency (UHF) band around 868 MHz, this antenna is designed on a flexible plastic substrate of relative permittivity 3 and low tangential losses which is 0.002. The proposed tag is designed to identify clothing in supermarkets. The tag antenna has a miniature size of 38 mm in length and 26 mm in width. This miniature size was obtained by using two rectangular split ring resonator (RSRR). The impedance matching of the RFID chip with the antenna was carried out by a double T-matching structure. The antenna is designed, simulated and optimized using computer simulation technology (CST) microwave studio software and good results have been obtained in terms of impedance matching, gain and read range. [ABSTRACT FROM AUTHOR]

In this paper, a backfire suppressed aperture coupled circularly polarized (CP) stacked patch antenna for universal ultra-high frequency (UHF) radio frequency identification applications is presented. Cross-polarized backfire radiation patterns were successfully suppressed by a planar high impedance surface (HIS) reflector. The size of the fabricated antenna is 250 × 250 × 26.9 mm3 (0.71λ0 × 0.71λ0 × 0.076λ0) and its peak gain value of 7.1 dBi is measured. The distance between the antenna and the HIS reflector is only 4.8 mm (0.014 λ0). The HIS reflector suppressed cross-pol backfire radiations by about 10 dB. Detailed antenna and HIS reflector design are discussed thoroughly in this paper. The presented backfire suppression technique using the HIS reflector is scalable to other applications and frequency bands. This paper demonstrates the feasibility of the HIS structure at UHF band. [ABSTRACT FROM AUTHOR]

In this communication, a planar inverted-F antenna (PIFA) structure is employed for the realization of a compact and low profile metal mountable tag device for ultrahigh-frequency (UHF) radio frequency identification (RFID). In order to compensate dielectric parameters and/or tag chip impedance variations, and the effects of manufacturing tolerances or other imperfections which can cause severe performance degradation at the target frequency, a tag structure with three lumped elements and a U-shape slot with adjustable length for post-manufacturing working frequency and impedance matching tuning is proposed. In order to simplify the post-manufacturing tuning process, both the PIFA and the tag chip matching network are designed to match an intermediate $50~\Omega $ real impedance, which makes it possible to easily verify the impedance matching performance. A $29.8\times 29.8\times0.813$ mm3 prototype is manufactured for the 920.5–924.5 MHz Chinese bandwidth, and it has been verified that the post-manufacturing tuning operation can effectively restore the design working frequency, with a read range of 3.6 m at 922.5 MHz when the tag is mounted on a $10\times10$ cm2 aluminum plate. [ABSTRACT FROM AUTHOR]

Ultrahigh frequency radio-frequency identification (UHF RFID) tags have shown enormous potential in wearable applications for sensing human vital signs. However, the integration of UHF RFID tags in clothing to achieve machine washability remains a challenge. In this study, we investigated different ways of protecting wearable UHF RFID tags with electro-textile antennas against repeated washing. We replaced the antennas of commercial UHF RFID tags with the antennas made from a silver-coated fabric. Twenty-three types of methods, including five integrated circuit (IC)-protection methods and seven fixation/cover methods, were compared, with each having ten identical samples. The 230 samples underwent 20 cycles of machine washing and drying, and the changes in received signal strength indicator (RSSI) and the number of failed tags after washing were recorded and analyzed statistically. We found that 1) water penetration does not have a negative impact on tag functionality, therefore, being waterproof is not a requirement for the coating material; 2) heat-bond hem taping is the most efficient IC protection method; 3) heat and high pressure is effective to improve tag endurance; and 4) fusible interlinings and ironing, used in traditional garment production, can be effective. [ABSTRACT FROM AUTHOR]

This paper presents a method to increase the detection range for RFID readers in the UHF radio band. The design is following especially the ISO 18000-6C standardization demands for the UHF band, operating from 865 to 868 MHz in Europe and from 902 to 928 MHz in North America. These regulations are allowing the RFID tags to operate near the metallic surfaces and in a wider range than its counterparts at lower frequencies. The paper highlights the advantages offered by the array antenna, especially by the beamforming to increase the reader surveillance zone. The paper describes some additional techniques that are allowing the usage of the circular polarization to increase the reader sensing range and to improuve detection. The design starts with simulation and optimization using HFSS and ends with the measurements that validate the simulation results. [ABSTRACT FROM AUTHOR]

The present topic review article will present the support provided by a technology based on microchips and RFID elements in processes of identification and detection of vehicles, offering solutions more precisely on the insecurity of them, evidenced in the evasion of the authorities and thefts of auto parts. The use of information technology and telecommunications (ICT) offers an innovative solution for the management of vehicle's information that allows to counteract criminal actions and their impact, specifically the use of cars in illicit activities in which their information is altered in order to evade the authorities. A support system based on ICT is proposed, which promises to optimize the current benchmarks of vehicular safety, offering tools to support benchmarks which are used nowadays such as the use of cameras and speed radars so that, they will help to improve the processes in the validation of information, providing faster and more secure access. This RFID technology is proposed to be implemented in a microchip, through which a unique code will be obtained, not forgetting that it allows the microchip to be connected to a network of distributed databases, which will allow access to the vehicles' own information, through an RFID reader device equipped with antennas compatible with UHF signals, facilitating the reception of the signal at distances over 5 meters away from the target and being able to identify it from far away locations, allowing to obtain information from vehicles with better effectiveness in order to control the problems about the one that are in illicit problems. [ABSTRACT FROM AUTHOR]

A miniaturized UHF dual‐band passive RFID tag antenna operating in the 866‐869 and 950‐956 MHz bands is proposed. It consists of an S‐shaped Folded Dipole Antenna (FDA) resonating at 912 MHz, which is intermediary between the two required frequencies. To obtain dual‐band response perturbation method is employed. The electrical length of the FDA changes on loading a 2‐turn spiral resonator (2‐SR) to it. The 2‐SR splits the tag resonance at 912 MHz into two resonance frequencies (867 and 956 MHz). The proposed design is simulated using HFSS and then fabricated. Measured reflection coefficients at 867 and 956 MHz are −13.25 and −13.34 dB, respectively, exhibiting a 10 dB bandwidth of 11 MHz from 859 to 869 MHz and a 5 MHz 10 dB bandwidth from 953 to 957 MHz. Maximum read ranges of 5 m in 866‐869 MHz and 3.3 m in 950‐956 MHz band have been measured. [ABSTRACT FROM AUTHOR]

A conformal radio frequency identification tag antenna can be integrated into printed circuit board (PCB) is presented. The simulation and experiment results indicate that the proposed tag can be reached as being applied on stacked PCB boards or separated PCB board. The design area of the proposed tag is 6 × 46 mm, which is small enough for most PCB boards. And it is also proved that the proposed tag can be used in PCB boards with different thicknesses. The maximum read range is measured to be 2.7 and 3.5 m as the tag is deployed on stacked PCB boards and separately placed PCB boards. [ABSTRACT FROM AUTHOR]

Abstract A compact meandered cross-shaped slot circularly polarized antenna for ultra high frequency (UHF) band radio frequency identification (RFID) reader applications is presented. Circularly polarized radiation is realized by introducing a slot on the diagonal axis of a square patch. Four different slot shapes are entrenched on one of the diagonal axes of the square patch for circularly polarized radiation and compared to the fixed overall volume of the antenna. The overall size of the antenna is reduced by increasing the perimeter of a slot within one quadrant of the patch. The meandered cross-shaped slot circularly polarized antenna is compact when compared with circular-, square- and cross-shaped slot circularly polarized antennas. Diagonally symmetric two- and four-meandered cross-shaped slot antennas are studied for further size miniaturization. Measured 3 dB axial ratio bandwidth of around 6 MHz with more than 2 dBic boresight gain and 10-dB reflection coefficient of 22 MHz is obtained with circularly polarized meandered cross-shaped four slot antenna. Size of the antenna is 0.189 λ 0 × 0.189 λ 0 , where λ 0 is the operating wavelength at 915 MHz. [ABSTRACT FROM AUTHOR]

A compact in-metal ultrahigh frequency radio frequency identification tag for identification of metal components is described. The radiating element is printed on a $23\times 23 \times 1$ mm3 copper-clad alumina (Al2O3) substrate ($\varepsilon _{\mathbf {r}} = 9$ , tan $\delta = 0.0003$) and consists of two rectangular quarter-mode patch antennas properly arranged to make the tag performance as robust as possible even when the tag is embedded in small cavities carved out of metal objects. The entire structure has been optimized by taking into account the presence of a thin superstrate of commercial epoxy resin used to protect the tag. The effect of the cavity size on the tag performance is numerically analyzed. Measurements on a tag prototype are also described and discussed. [ABSTRACT FROM AUTHOR]

A new type of C-shaped antenna, which is designed by combining a loop antenna and a planar inverted-L antenna, is proposed for designing a miniature tag antenna for on-metal applications. The proposed tag antenna can be easily made by folding a piece of flexible substrate. It is electrically small and low in profile, with a circuit size of 40 mm $\times40$ mm $\times1.6$ mm ($0.122\lambda \times 0.122\lambda \times 0.005\lambda$). The antenna consists of five patch segments, which can be adjusted for achieving multiple degrees of tuning freedom. By tuning the antenna impedance, a conjugate match can be easily obtained. When mounted on a $20 \times 20$ cm2 metal plate, the proposed tag antenna is able to achieve a maximum read distance of 9.2 m with equivalent isotropic radiated power of 4 W, which is much better than the conventional loop antenna. The operating frequency of the proposed tag antenna is found to be very stable and it is not affected much when the dimensions of the backing metal object are varied. [ABSTRACT FROM AUTHOR]

In this article, a miniaturized ultra‐high frequency (UHF) microstrip traveling wave antenna (TWA) array for cm‐level 2D identification (ID) and position detection systems is proposed. The proposed miniaturized TWA array with nine reading zones for ID and position detection systems has been reduced in size by utilizing LC‐baluns and a microstrip TWA array. It covers the authorized universal UHF radio frequency ID band (840‐960 MHz), has low insertion loss (0.8 dB), and high isolations between TWAs are ≤30 dB. The sensing precision of the proposed TWA array is approximately 1.5 cm and its physical size is 95 × 95 mm2 (~1/4 λ0 at 915 MHz). [ABSTRACT FROM AUTHOR]

Radio frequency-identification finger-augmented devices (R-FAD) identify a particular wearable technology suitable to turn the human fingers into enhanced sensing surfaces to restore lost senses in impaired people as well as to augment the existing ones. The communication channel of R-FAD, involving a reader’s antenna placed onto the wrist and tag antennas stuck onto the fingers, is here characterized in the UHF radio frequency identification (RFID) band by means of both numerical simulations, accounting for several options of the system, and an experimental campaign with volunteers asked to reproduce natural gestures of the hands. The study identifies the most appropriate placement of the devices and, above all, it quantifies the robustness of the link against the human variability. The channel follows a lognormal cumulative probability law indicating that the minimum required power to establish a reliable RFID link is 18–27 dBm depending on the chip sensitivity. Measurements finally revealed a remarkable correlation of the minimum required power from the reader with the volume of the hand. [ABSTRACT FROM AUTHOR]

A novel printed center-fed dual-log-periodic array antenna is proposed for ultrahigh frequency (UHF) radio frequency identification (RFID) applications. The proposed antenna is composed of two reversed wideband printed log-periodic dipole array antennas. Two closely spaced oppositely directed currents are thus introduced to achieve intensive and uniform magnetic fields in the near-field zone. A prototype antenna is fabricated and measured in practical application environment. The measurement results agree well with the simulations, and demonstrate that the proposed antenna is suitable to be implemented in RFID systems. The operated frequency band of the antenna is 824–953 MHz (14.5%), covering the UHF band in China, the Federal Communications Commission band, and the European Telecommunications Standards Institute band. With the proposed printed dual-log-periodic array antenna, measurement results also show that the RFID system delivers a 100% guaranteed reading rate within 2.0 cm and a maximum reading range of 19.0 cm. [ABSTRACT FROM AUTHOR]

A zero-phase-shift-line (ZPSL) loop array with two closely spaced elements is proposed to achieve a directional distribution for ultrahigh frequency (UHF) near-field radio frequency identification (RFID) applications. The proposed array consists of two coaxially positioned ZPSL loop antenna elements of the same size, with an aperiodic ZPSL loop acting as a driven element and a periodic ZPSL loop functioning as a parasitic element. A directional magnetic field distribution can be achieved when an out-of-phase current along the parasitic loop is induced. A ZPSL loop array prototype with an interelement spacing of 15 mm, or 0.046 of the operating wavelength at 915 MHz, achieves a desired directional magnetic field distribution over a circular interrogation zone with a diameter of 160 mm. As a UHF near-field RFID reader antenna, the proposed array is able to achieve a 100% detection rate of SAG tags up to 120 mm by using an Impinj Speedway reader with an output power of 30 dBm. [ABSTRACT FROM AUTHOR]

A novel printed antenna is designed for wearable and RFID applications in the UHF band. The antenna design is performed following energy-based design guidelines available in the recent literature. High robustness with respect to the human body coupling is achieved by confining the electric energy density in a region far from the antenna borders. The proposed configuration also provides a compact realization, and a high versatility, since it can be easily matched to different commercial chips. A prototype of this wearable antenna has been manufactured and tested in an anechoic environment. Experimental measurements of the read range confirm the results of the numerical simulations and demonstrate the antenna robustness with respect to the variations of the body–antenna coupling scenario. [ABSTRACT FROM AUTHOR]

A miniature folded patch with a dimension of $40\,\,\text {mm} \times 40\,\,\text {mm} \times 1.6\,\,\text {mm}\,\,(0.1156\lambda \times 0.1156\lambda \times 0.0046\lambda $ at 867 MHz) is proposed for designing a passive metal-mountable tag. It consists of a square patch which is equally separated into two rectangular patches. Since the patch resonator usually has high resonant frequency, multiple tuning mechanisms are always needed to bring down the frequency so that it can be used for designing a tag antenna in the UHF band. In the proposed design, each patch is incorporated with a C-shaped slot and three thin inductive stubs for performing different levels of frequency tunings. An equivalent circuit has been built for estimating the input impedance of the antenna. Reasonable agreement is found between the measured, modeled, and simulation results. The proposed tag antenna is readable from 5 m with an EIRP of 3.28 W when placed on a 20 cm $\times20$ cm metal plate. [ABSTRACT FROM AUTHOR]

Multistate chips for an UHF radio frequency identification ensure self-compensation of the variations in antenna impedance. This self-tuning capability can provide a digital information about the change in local boundary conditions within the vicinity of the tag. This feature can be exploited further for low-cost wireless sensing applications. An electromagnetic model of the tag in linear and nonlinear regimes allows prediction of analog and digital responses of the device depending on the boundary conditions that cause the variation of the antenna impedance and/or gain. In addition, the model provides estimation of the degradation in communication performance of the tag due to imperfect retuning of the chip impedance. The theoretical findings of the model are verified in sensing applications using a reference self-tuning tag. Sensing measurements of liquid compounds in linear regime and of the water-filling level of a box in nonlinear regime are demonstrated as a practical application of the proposed mathematical model. [ABSTRACT FROM AUTHOR]

The robustness of wearable antennas to the human body proximity can be improved by properly placing the radiating element over a ground plane, or by shaping the ground plane, on the basis of the antenna electric and magnetic energy density distributions, aiming to confine the electric energy density in specific regions far from the antenna border. The effectiveness of the above design criterion has been assessed through both numerical analysis and experimental measurements, by optimizing the position of the radiating element of a wearable grounded ultrahigh frequency radio frequency identification tag operating at the ETSI band (865–868 MHz), with respect to its ground plane. A flexible tag characterization and performance evaluation platform is used to measure the tag sensitivity as a function of the antenna-body distance. [ABSTRACT FROM AUTHOR]

We compare the performance of equal-sized dipole and folded dipole wearable passive UHF RFID tags using three different body models for the torso of an adult male: cuboid and anatomical models with and without internal structures. The results show that all models estimate the antenna impedance matching appropriately, but only the anatomical models predict the full spatial coverage of the tags properly. We present a novel metrics for analysing the coverage in simulations and compare the simulated and measured tag read ranges to validate our modelling results. [ABSTRACT FROM AUTHOR]

A folded patch, which is centrally fed by a coplanar feedline, is proposed for designing a miniature UHF tag antenna for mounting on metal surfaces. The tag is designed using a flexible polyethylene terephthalate substrate with a very compact size of 25 \text mm \times 40\,\,\text mm \times 3 mm ( $0.0767\lambda \times 0.123\lambda \times 0.0092\lambda$ ). Conjugate match is attainable between the antenna and the microchip and it is able to achieve a maximum read distance of 10.7 m at the effective isotropic radiated power of 4 W. In the design, two notches have been incorporated with an inductive stub for tuning of the tag’s resonance over a larger frequency range. Also, a simple equivalent circuit has been derived to characterize the impedance of the tag antenna. The resonant frequency of the proposed tag antenna is found to be insensitive to various sizes of the backing metal object, which is a very desirable feature for tag design. The proposed tag can achieve a read distance of greater than 10 m when placed on metal. It is able to be read beyond 5 m when it is placed on dielectrics with permittivity in the range of 1–5.8. [ABSTRACT FROM PUBLISHER]

This paper presents a measurement method for tagged item classification in radio frequency identification (RFID)-based smart drawers. Specifically, the amplitude of the signal backscattered by the UHF-RFID passive tags attached to the items inside the drawer is used to identify at which of an assigned set of drawer subregions each detected tag belongs to. The received signal strength indicator (RSSI) may be acquired by almost any UHF-RFID commercial reader chipset compatible with the Electronic Product Code (EPC) Class1 Gen2 protocol. The RSSI model in terms of the position of the tag inside the drawer is introduced, and its selective properties are discussed through both numerical data and measurements. The cases of a single reader antenna measuring during natural opening/closing operations as well as of multiple reader antennas measuring when the drawer is static are investigated. The measurement method performance is shown through an experimental analysis in a realistic scenario, where the RSSI values are collected by using commercial UHF-RFID hardware components, and then used as the feature vector of the classification algorithm. As an example, two different classifiers are used to map each detected tag to one of the regions that the drawer is subdivided into. The classification performance of the method based on a single antenna exploiting the drawer natural sliding movements is comparable to that achievable with multiple reader antennas, while representing a cost-effective and easy-to-implement practical solution. [ABSTRACT FROM PUBLISHER]

The recently introduced inkjet printing technology with ambient sintering is here investigated for the fabrication of epidermal antennas suitable for radio-frequency identification (RFID) and sensing. The attractive feature of this manufacturing process is the possibility to use low-cost printers without any high-temperature curing. In spite of the estimated maximum achievable conductivity of the ink ( \sigma \text {UHF}=1\times 10^{5} S/m) in the UHF-RFID band that is two orders of magnitude lower than that of the bulk copper, a threefold printing process provides the same on-skin radiating performance as manufacturing technologies using bulk conductors. Experiments demonstrate that the epidermal antennas printed on the PET substrate are insensitive to moderate mechanical stress, like the natural bending occurring over the human body, and to the possible exposure to body fluids (e.g., sweat). Moreover, the electromagnetic response remains stable over the time when the printed layouts are coated with biocompatible membranes. [ABSTRACT FROM PUBLISHER]

A circularly polarized, broad bandwidth, square-ring patch antenna for radio-frequency identification (RFID) is proposed. The antenna has a dimension of 100 × 100 × 22.9 mm 3 . By using a Wilkinson power divider and a patch-antenna structure, a measured 3-dB axial-ratio bandwidth of approximately 140 MHz (16.47%), an impedance bandwidth of 136 MHz (15.81%), and a measured peak gain of approximately 6.8 dBic are being achieved. The operating band of the proposed antenna is suitable for China (840–846 MHz), Europe (865–868 MHz) and the United States (902–928 MHz) ultra-high frequency (UHF) RFID applications. [ABSTRACT FROM AUTHOR]

Abstract: The RFID technology is widely improved in the last decade. It offers different applications touching different areas. Tags could be modeled under several shapes serving the desired application; it can take a wristband form in the case of human body identification. In this paper, we present a design of an antenna implemented on the tag, with the aim to sense different physiological human parameters (temperature, blood pressure, O2 saturation, etc.). This antenna has a bent form, suitable for the medical application. It was put on flexible substrate to be conformal to the wrist. It presents good characteristics in terms of impedance matching. [ABSTRACT FROM AUTHOR]

The design of an ultrahigh-frequency (UHF) radio-frequency identification (RFID) reader antenna covering an electrically large near-field area is challenging for near-field UHF RFID applications. In such a design, magnetic field distribution on a large coverage area is required to be as uniform as possible. For some specific UHF near-field RFID applications, given radiation pattern characteristics are expected. A fragment-type wire structure is quite suitable for these demands because uniform magnetic field distribution and given patterns could be generated through optimizing the fragmented wires in a designated electrically large area to obtain corresponding current distribution. In this article, the concept of a fragment-type structure as well as some design guidelines are reviewed and summarized. Then, two omnidirectional fragment-type wire antennas with different cell size and two directional fragment-type wire antennas are designed. Both simulation and experiment results show that there is no reading null within an electrically large near-field zone having a perimeter of four operating wavelengths at 915 MHz (i.e., 320 mm x 320 mm). The omnidirectional designs are promising in the applications of UHF near-field RFID tag detection in self-confined volumes, and the directional designs are potential in the systems of UHF near-field/far-field RFID. [ABSTRACT FROM PUBLISHER]

Radio-frequency identification (RFID) is being widely used in supply chain and logistics applications for wireless identification and the tracking and tracing of goods, with excellent performance for the long-range interrogation of tagged pallets and cases (up to 4-6 m, with passive tags). Item-level tagging (ILT) has also received much attention, especially in the pharmaceutical and retail industries. Low-frequency (125-134 KHz) and high-frequency (HF) (13.56 MHz) RFID systems have traditionally been used for ILT applications, where the radio-frequency (RF) power from the reader is delivered to the passive tags by inductive coupling. Recently, ultra-HF (UHF) (840-960 MHz) near-field (NF) RFID systems [1] have attracted increasing attention because of the merits of the much higher reading speed and capability to detect a larger number of tags (bulk reading). A UHF NF RFID system is a valuable solution to implement a reliable short-range wireless link (up to a few tens of centimeters) for ILT applications. Because the tags can be made smaller, RFID-based applications can be extended to extremely minuscule items (e.g., retail apparel, jewelry, drugs, rented apparel) as well as the successful implementation of RFID-based storage spaces, smart conveyor belts, and shopping carts. [ABSTRACT FROM PUBLISHER]

The paper aims at developing an application regarding the use of RFID systems to identify objects present in harsh industrial environments. The structure and properties of passive RFID tags for normal environment and the ways of designing and manufacturing the RFID tags resistant to the aggressive environments are described. The research carried out resulted in the design, development, testing and validation of a RFID tag whose features enabled the implementation of the RFID system in the harsh environment of an industrial laundry. [ABSTRACT FROM AUTHOR]

The aim of the research outlined in this paper is to demonstrate the implementation of a Cyber-Physical System (CPS) within the End of Life (EoL) processing of Electrical and Electronic Equipment (EEE). The described system was created by reviewing related areas of research, capturing stakeholder's requirements, designing system components and then implementing within an actual EoL EEE processer. The research presented in this paper details user requirements, relevant to any EoL EEE processer, and provides information of the challenges and benefits of utilising CPSs systems within this domain. The system implemented allowed an EoL processer to attach passive Ultra High Frequency (UHF) Radio Frequency Identification (RFID) tags to cores (i.e. mobile phones and other IT assets) upon entry to the facility allowing monitoring and control of the core's refurbishment. The CPS deployed supported the processing and monitoring requirements of PAS 141:2011, a standard for the correct refurbishment of both used and waste EEE for reuse. The implemented system controls how an operator can process a core, informing them which process or processes should be followed based upon the quality of the core, the recorded results of previous testing and any repair efforts. The system provides Human-Computer Interfaces (HCIs) to aid the user in recording core and process information which is then used to make decisions on the additional processes required. This research has contributed to the knowledge of the advantages and challenges of CPS development, specifically within the EoL domain, and documents future research goals to aid EoL processing through more advanced decision support on a core's processes. [ABSTRACT FROM AUTHOR]

A cost-effective solution for in situ antenna characterization and diagnostics based on Radio Frequency IDentification technology and Remotely Piloted Aircrafts is presented. The cost-effectiveness of the proposed solution is achieved by replacing the radio frequency equipment on-board the small aircrafts with Radio Frequency IDentification tags, while the Antenna Under Test is connected to a Radio Frequency IDentification reader, thus reducing the weight and complexity of the payload of the aircrafts dedicated to antenna measurement task. Received Signal Strength measurements are geo-referred with centimeter-level accuracy thanks to a Real Time Kinematic system. An iterative phase retrieval technique based on the Sources Reconstruction Method is used to recover an equivalent magnetic currents distribution on the Antenna Under Test aperture plane. The reconstructed currents distribution provides antenna diagnostics information and enables the calculation of the antenna radiation pattern. The presented method has been validated by means of measurements in the UHF band for two different antenna arrays with excellent results. [ABSTRACT FROM AUTHOR]

A wide half-power beamwidth antenna based on magnetic coupling in near-field (NF) regions and circular polarization (CP) in far-field (FF) is proposed for RFID multiservice applications in UHF band. The prototype consists of a cross-strip and an L-shaped strip on the top layer, fed by an F-shaped network on the bottom layer. CP electromagnetic wave is radiated by the cross-strip, and the antenna also simultaneously brings opposite directed currents (ODC) to generate strong magnetic field in near-field region. Half-power beamwidth is 100° in xoz-plane and 102° in yoz-plane, which can be used to scan for large regions. An 88 x 88 x 1.6 mm ³ antenna has been fabricated on an FR-4 substrate to fit RFID applications. Measured tests on read range by observing feedback received signal strength indication (RSSI) values are carried out, exhibiting 100% read rate for near-field tags within 25mm and exciting read distance for far-field tags up to 1m for large reading region of 170 x 170 mm². [ABSTRACT FROM AUTHOR]

Two reader antennas, which are designed using the L-probe-fed suspended patch, are designed for the UHF band. To generate circular polarization, the Lshaped probe is modified by including an extra bend to provide one more degree o f tuning freedom to the reflection coefficient without affecting the axial-ratio performance much. The proposed single-element reader antenna is able to achieve a CP bandwidth of 5.5 % (890 MHz to 940 MHz) and a maximum antenna gain of 9.7 dBi. When designed into a 2x2 array, the proposed reader antenna is able to produce CP bandwidth of 5.3 % (910 MHz to 960 MHz) with an antenna gain of 14.7 dBi. The read ranges of the proposed antenna and its array are 6.3 m and 10.9 m, respectively. [ABSTRACT FROM AUTHOR]

In this paper, a new design of miniaturized passive UHF RFID tag antenna using double negative metamaterial based on fractal split ring resonator is proposed. This tag antenna is designed on paper substrate having dielectric constant of 3.3, tangent loss of 0.04 and height of 250 micrometers. The effective read range can be obtained when the input impedance of the antenna is conjugate match with the complex impedance of the RFID chip. The dimensions of the metamaterial tag antenna are optimized and simulated by using the electromagnetic solver Momentum integrated in ADS. The obtained result was validated by CST Microwave Studio. The proposed tag antenna is designed to cover the North and South American UHF RFID band (902- 928MHz). The input impedance bandwidth of the proposed tag antenna is 28 MHz (from 902MHz to 928MHz), the reflection coefficient is about -35dB and the simulated gain is about 1.73dB. [ABSTRACT FROM AUTHOR]

A very small size radio frequency identification (RFID) tag antenna specifically designed for racing pigeon ring applications is proposed. The structure of this UHF tag is a closed-loop type printed on a 30 × 8 mm2 polyimide film of thickness 0.063 mm. Thus, it can be wrapped into a double layer plastic cylindrical ring of size similar to those used for racing pigeon. By simply tuning the inner width of the loop, good conjugate matching between the tag chip input impedance and the tag antenna can be achieved. When mounted onto a real preserved dried pigeon feet specimen, the measured impedance bandwidth of the tag antenna was 901-929 MHz. Further experimental results have also shown that the proposed antenna has a maximum reading range of up to 50 cm. [ABSTRACT FROM AUTHOR]

In this paper, a dual-band high frequency (HF) and ultra-high frequency (UHF) radio-frequency identification (RFID) tag antenna is presented that operates in the 13.56 MHz band as well as in the 920 MHz band. A spiral coil along the edges of the antenna substrate is designed to handle the HF band, and a novel meander open complementary split ring resonator (MOCSRR) dipole antenna is utilized to generate the UHF band. The dual-band antenna is supported by a single-feeding port for mono-chip RFID applications. The antenna is fabricated using an FR4 substrate to verify theoretical and simulation designs, and it has compact dimensions of 80 mm × 40 mm × 0.8 mm. The proposed antenna also has an omnidirectional characteristic with a gain of approximately 1 dBi. [ABSTRACT FROM AUTHOR]

We propose a wide bandwidth antenna with a circular polarization for universal Ultra High Frequency (UHF) radio-frequency identification (RFID) reader applications. To achieve a wide 3 dB axial ratio (AR) bandwidth, three T-shaped microstrip lines are inserted into the ground plane. The measured impedance bandwidth of the proposed antenna is 480 MHz and extends from 660 to 1080 MHz, and the 3 dB AR bandwidth is 350 MHz and extends from 800 to 1155 MHz. The radiation pattern is a bidirectional pattern with a maximum antenna gain of 3.67 dBi. The overall size of the proposed antenna is 114 × 114 × 0.8 mm3. [ABSTRACT FROM AUTHOR]

This paper presents our investigation into a novel ultrahigh-frequency (UHF) radio frequency identification (RFID) multipolarized reader antenna based on a pair of symmetrical meandering open-ended microstrip lines for near-field applications. The near-field and multipolarization operation is achieved by introducing a 90° phase shift between the currents flowing along the opposite side of two branches. The proposed antenna is shown to generate a uniform and strong electric field in its near-field region within a reading volume: 450~\text mm \times 450~\text mm \times 350 mm ( \text width \times \text length \times \text height ). The simulated and measured impedance bandwidths (−10 dB) agree very well, ranging from 825 to 965 MHz and covering the UHF RFID standard. In addition, it exhibits a low far-field gain, avoiding to misreading the tags outside the near-field region. The fabricated antenna was fully tested with multiple tag antennas that are placed in different orientations and even in a conveyor system, demonstrating a 100% reading rate of arbitrarily oriented tags within the reading zone. [ABSTRACT FROM AUTHOR]

The use of complementary split-ring resonators (CSRRs) as radiating elements in low-profile on-metal ultra-highfrequency radio-frequency identification (UHF-RFID) tags is explored in this study. First, the radiation properties of the edgecoupled and the non-bianisotropic (NB-CSRR) versions of the CSRR are studied. The tag design strategy is then discussed in detail. On that basis, a compact (λ0/7 x λ0/7) low-profile (1.27 mm) tag prototype based on the non-bianisotropic version of the CSRR (NB-CSRR) antenna is designed and manufactured to operate in the North-American UHF-RFID band. The experimental results validate the theoretical and simulated behaviour, and exhibit a maximum read range of 6.8 m. [ABSTRACT FROM AUTHOR]

A small size and low-profile antenna has been developed in order to provide any mobile phone with ultra-high frequency (UHF) radiofrequency identification (RFID) reader functionality. For that purpose, a patch antenna topology has been chosen on account of the mobile phone battery, which exhibits an electromagnetic behaviour similar to a metal plane. The lowprofile patch antenna has been designed to operate at the European UHF RFID band. To communicate the mobile phone with the RFID reader module, near-field communication (NFC) technology has been considered. Thus, an NFC antenna, based on square coils, operating at 13.56 MHz has been also designed. Such antenna has been etched on the opposite side of the patch antenna. Overall dimensions of the prototype are 60 mm × 100 mm, i.e. small enough to fit the dimensions of a mobile phone. As proof of concepts to evaluate the performance of the designed antennas, an UHF RFID reader module and an NFC reader module are tested. The measured read range reaches up to 1 m for some commercial tags. [ABSTRACT FROM AUTHOR]

A dual-broadband circularly polarized (CP) antenna with compact structure 97 x 97 x 0.8mm³ is proposed. The measured -10 dB return loss bandwidth is 0.38 GHz (0.75-1.13 GHz) for UHF band and 0.81GHz (2.32-3.13 GHz) for ISM 2.4GHz band. The measured 3 dB axial ratio bandwidth is about 0.235 GHz (0.83-1.065 GHz ) for UHF band and 0.34GHz (2.36-2.7 GHz) for ISM band. The antenna consists of a feedline, patch, Stepped slot-1 and -2, a pair of orthogonal rectangular slots (H/V slot), and an L-slot. There are two advantages for the proposed antenna: broadband and independent adjusting for UHF and ISM 2.4GHz bands. The proposed antenna is a good candidate for worldwide RFID reader antenna. [ABSTRACT FROM AUTHOR]

A compact UHF range RFID antenna with Circular Polarization (CP), which is proposed in this paper consists of stair shaped edge with irregular slots on one side and L-shaped feed line on the other. The L-shaped structure improves the Circular Polarization of antenna and provides CP mode at 2.68 GHz under UHF frequency range which is suitable for RFID applications. This antenna also provides bandwidth for RFID reader with -10 dB return loss (reflection coefficient) and have 3 dB axial ratio (AR<3 dB) and impedance bandwidth (VSWR < 2) in the operating frequency band. [ABSTRACT FROM AUTHOR]

A coin-shaped folded dipole is proposed for designing a UHF tag that can be placed in free space and on metal. The proposed tag antenna is compact ( $0.095\lambda )$ and low in profile (1.6 mm). It is composed of a matching loop, which is encircled by two patch-shaped radiating arms, forming an embedded structure that has high compactness. Slots are etched in the radiators for fine-tuning the resonant frequency. An equivalent circuit has also been obtained for analyzing the impedance characteristics of the tag antenna across the frequency range, and it is found that the radiating element itself is capacitive and inclusion of the matching loop is essential for making the tag antenna inductive for achieving good matching with the chip. Simulation and experiment have been conducted to study the charateristics of the proposed tag antenna. When tested in free space with an Effective Isotropic Radiated Power (EIRP) input power of 3.28 W, the tag antenna is able to reach a maximum read range of 5.2 m, but it reduces to 1.8 m when placed on metal. Also, the resonant frequency of the proposed tag antenna is found to be stable and not affected much by its backing object. [ABSTRACT FROM PUBLISHER]

ABSTRACT A significant cost in the widespread deployment of UHF radio frequency identification (RFID) systems has been the passive RFID tags. To address some of this expense, this paper presents an antenna design for UHF RFID tags that can be printed on inexpensive paper substrates and operate in the near field of the UHF reader. This antenna design is based on meander line miniaturization techniques and open complementary split ring resonator (OCSRR) elements to reduce the amount of conducting material required to manufacture the antenna by 30%. For demonstration purposes, a prototype near-field UHF RFID tag was manufactured on a paper substrate and the read-range was measured at 920 MHz. It was shown that useful read-ranges could be achieved while reducing the overall cost and size of the antenna on the RFID tag. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:1052-1056, 2017 [ABSTRACT FROM AUTHOR]

ABSTRACT A novel miniaturized UHF RFID tag antenna (26.4 × 24 × 1.6 mm3) for broadband operation over the UHF RFID band with good read range characteristics are proposed. The tag consists of a T-matched dipole antenna with tapered meandered arms whose ends are folded to one side and an RFID chip is connected to the terminals of the antenna. The resonant frequency can be tuned by varying the gap width between the folded arms so that maximum read range can be achieved in the required territory's allotted band, without affecting its overall size. The measured read range variations with angular ranges for the proposed tag designed for maximum read range at 915 MHz are also presented. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:1142-1145, 2017 [ABSTRACT FROM AUTHOR]