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The near-field ultrahigh-frequency (UHF) quadruple-loop antenna (QLA) with uniform field distribution for item-level tagging is proposed. The proposed antenna consists of quadruple fan-shaped small loops and the middle feeding lines of each loop located at the top and bottom of the substrate using vias. The currents flowing through feeding lines are cancelled due to opposite directional currents (ODCs), and the proposed QLA operates as one large loop electrically. From this configuration, the proposed antenna achieves more uniform field distribution and a precise interrogation zone than conventional loop antennas. Compared to the conventional loop antennas with different sizes, the proposed antenna using the uniform field distribution achieves a interrogation zone of 40 × 40 mm $^2$ at up to approximately 50 mm.

This paper presents a novel inkjet-printed near-field ultra-high-frequency (UHF) radio frequency identification (RFID) tag/sensor design with uniform magnetic field characteristics. The proposed tag is designed using the theory of characteristics mode (TCM). Moreover, the uniformity of current and magnetic field performance is achieved by further optimizing the design using particle swarm optimization (PSO). Compared to traditional electrically small near-field tags, this tag uses the logarithmic spiral as the radiating structure. The benefit of the logarithmic spiral structure lies in its magnetic field receiving area that can be extended to reach a higher reading distance. The combination of TCM and PSO is used to get the uniform magnetic field and desired resonant frequency. Moreover, the PSO was exploited to get a uniform magnetic field in the horizontal plane of the normal phase of the UHF RFID near-field reader antenna. As compared with the frequently-used commercial near field tag (Impinj J41), our design can be readable up to a three times greater read distance. Furthermore, the proposed near-field tag design shows great potential for commercial item-level tagging of expensive jewelry products and sensing applications, such as temperature monitoring of the human body.

This paper proposes a novel methodology for designing near-field fractal antenna operating at European Ultra-High Frequency (UHF) for Radio Frequency Identification (RFID) systems. The principle of Oppositely Directed Current (ODC) technique is implemented to generate homogeneous magnetic field above the surface area meant for near-field RFID application. The conceptual theoretical framework of the design based on the fractal structure can be applied. The fabricated RFID reader antenna operates at 867 MHz with reflection coefficient S11 -30 dB, thus the reader antenna covering UHF RFID band range. The reading capabilities of the antenna are determined by the interrogation area of, 190mm x 243mm. It is adequate for object tracking and detection systems in pharmaceutical management and chemical industries.

RFID systems have been adopted by several sectors in societies for a wide set of applications, ranging from item level tagging to supply chain management. One of the most important RFID applications is tag identification, which is a process executed in an RFID network in order to distinguish the corresponding associated objects. Most of the research in this direction is aimed to the design of efficient communication protocols, which identify the whole set of tags in the covering region of an RFID reader. The common scenario comprises one reader and a set of tags, where the reader is generally located at the center of the interrogation zone; this scenario has been studied in several different ways with a centralized paradigm. However, there is a recent interest on analyzing an alternative scheme that consists in splitting the interrogation zone and executing a distributed mechanism to identify the whole set of tags. To date, some of the few contributions considering distributed approaches do not take into account a practical communication model. Thus, in this work we evaluate and compare the performance of both RFID tag identification paradigms using the EPC Class-1 Generation-2 standard and propose a practical communication model for such proposals distributing the identification process. Our results show that, indeed, the performance of the EPC Class-1 Generation-2 standard may be highly improved with the adoption of a distributed mechanism if all its features are fully exploited. Hence, the improvements obtained with our distributed proposal reach a gain of up to 65 % on the total identification delay compared with its centralized counterpart.

A new small on-metal UHF Radio Frequency Identification (RFID) transponder, 18 $\text {mm} \times 4 ~\text {mm} \times 2$ mm in size, is presented. The read range of the transponder has been optimized by using the most efficient radiator within the given maximum dimensions and even more importantly, by conjugate impedance matching between the small antenna and the microchip, which has been achieved by using antenna-integrated components. As a commercially viable solution is targeted, the bandwidth and the sensitivity of the antenna to the dimensional variation of the fabrication process have been studied and solutions for improved robustness are presented. After the study and optimization of the transponder, a series of prototypes was fabricated on printed circuit board. The measurement results of the prototypes showed good consistency with the simulations and a read range of 3.0 m was measured for a prototype mounted on a metal plate.

This paper presents 36-bit compact passive chipless RFID tag. The bowtie shape based tag structure is loaded with 36 slots. The tag is capable of yielding high data density. The overall tag dimension is 27mm × 26mm. The tag structure is optimized and analyzed for three different substrates, i.e., FR-4, Taconic TLX-0, and Rogers RT5880. Each loaded slot in tag structure has different length and hence yields resonance at particular frequencies. The response of the tag is observed through radar cross section (RCS) parameter. The 36-bit tag design can tag 236 objects/items. The passive chipless RFID tag produces resonances in the frequency band of 4–13GHz for FR-4 substrate and 5–15.5GHz using Taconic TLX-0 and Rogers RT5880 substrates. The ultimate cost-effective, compact chipless RFID tag can be deployed in various industrial applications. In future, further improvements can be made to integrate the concept of ‘green electronics.’

Depending on magnetic fields caused by phase differences between the adjacent transmission lines for high precision UHF near-field sectional localization systems, a four-port selective differential feeding network is presented. The proposed four-port feeding network consisting of four quadrature hybrid couplers and 90° phase delay lines can selectively generate a differential phased current on a particular transmission line. The maximum insertion loss within the authorized UHF RFID frequency band (902–928MHz) has a 7.1dB loss including the theoretical 6dB power distribution loss, and the maximum amplitude imbalances and phase error have less than ±0.5dB and ±10°, respectively. By switching the input ports, the sectional identification with regard to tag positions on the 10 mm height away from parallel transmission lines can be achieved. The proposed system using a four-port selective differential feeding network makes it possible to utilize a near-field position detection application such as a smart shelf.

This article investigates the effects of the environment on ultrahigh frequency (UHF) radio frequency identification (RFID) tags in both the near-field and far-field. Item-level tagging has always been challenging due to the negative impact of metals on RFID. Full-scale RFID item-level tagging has always been difficult to integrate in retail (department) stores. This UHF RFID feasibility research examines the technical differences between near-field and far-field coupling by testing theoretical hypotheses through empirical experiments. These experiments are based on a specific case-study, where a distributor wants to tag multimedia objects. Based on the results obtained, we found that metal had less effect on the RFID tags in the near-field than in the far-field. In both cases the RFID tag was not readable, when placed directly onto metal. When the multimedia object itself was tagged, the reading range decreased to around half the free-space reading range in near-field and far-field. We can conclude that the RFID implementation in the retail store is feasible, but depends to a large extent on the product and its environment. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:718–727, 2014

A novel low-cost chipless radio frequency identification tag sensor is presented. The tag sensor provides identification data as well as monitors relative humidity (RH) of tagged objects. The tag sensor is made of passive microwave circuit that uses humidity sensitive polymer material for RH sensing. The aim of this paper is to investigate RF sensing properties of moisture absorbing polymer polyvinyl alcohol at microwave frequency. In addition, frequency shifting technique is used to encode data bits for high data capacity. The overall size of the proposed tag sensor is 15 mm × 6.8 mm and has 6 bit data capacity for ID generation and single bit for humidity sensing. Results presented here show ~ 607 MHz frequency deviation for 50% RH increase. The tag sensor has potential to be printed on flexible laminates such as plastic and paper for ultra-low cost item level tagging and ubiquitous sensing.

A novel compact design of an ultralow-cost fully printable slot-loaded dual-polarized chipless radio frequency identication tag is presented with four near- and far-field reading techniques. The tag consists of four rectangular metallic patches loaded with multiple slot resonators. Slots with the same polarization for adjacent frequencies are placed alternately into two patches to reduce the mutual coupling between the slots. Then two similar sets are placed in horizontal and vertical polarizations to double the number of bits within the same frequency bandwidth. The tag can be detected using dual-polarized waveguide(s) or dual-polarized antennas. This single-sided compact chipless tag has higher data capacity and lower cost compared with the existing printable chipless tags and can be used in personal ID or credit cards and banknotes and can be directly printed on paper or plastic packets for item-level tagging.

In this research, we study some of the operational benefits of item-level radio frequency identification (RFID), and how these benefits may affect the dynamics of the retailer-manufacturer interaction. We describe a retail operation with backroom and shelf stock under the assumption of multiple replenishment and sales periods, where backroom stock is replenished according to a periodic review order-up to policy and shelf stock is replenished continually from the backroom. In this environment, retail shelves are outfitted with RFID readers to continually monitor the remaining stock on the shelves and issue low-stock and replenishment alerts to store personnel so that shelves can be replenished from the store backroom before actual sales are lost at the shelf. We are interested in the dynamics between retailer and manufacturer with respect to the cost of item-level tagging the products. Of interest is the way in which the cost of tagging the product is divided among the two supply chain partners. To do this...

In this paper, we present a model to help evaluate the impact of an introduction of item-level radio-frequency identification (RFID) in a retail environment where stock-out-based substitution is common. There are two main thrust areas in this work. First, we examine the impact of RFID in a centralized setting where retailer and manufacturer are one entity. This thrust area is concerned with evaluating the profitability of RFID and exploring which product properties favor an RFID implementation. Second, we examine the impact of RFID in a decentralized setting, where retailer and manufacturer independently maximize their profits. We investigate the problem of sharing the costs of RFID, from both the perspective of tag costs and fixed costs. Our research shows that the presence of substitution at the shelf plays a major role in determining the expected benefits of an RFID implementation, as well as in determining the optimal allocation of these benefits among retailer and manufacturer. It is therefore critically important that decision makers make strong efforts to correctly account for subsitution effects when evaluating potential item-level RFID implementations in the retail sector.

A compact printable dual-polarized (DP) chipless RFID tag using slot length variation encoding technique in ‘I’ shaped slot resonators is presented in this paper with simulation and measurement results for barcode replacement. First, the ‘I’ shaped slot resonators are etched from a square metallic patch in both vertical (V) and horizontal (H) directions, which double the encoding capacity within a fixed frequency band by using the polarization sensitivity property of the ‘I’ slot resonators. Next, the slot length variation encoding technique is added to reduce the number of ‘I’ slots required for encoding data, which in turn reduces the tag size, and allows more gap between successive slots that reduces the mutual coupling and improves the printing tolerance. After that, a 16-bit proof of concept DP tag is designed, simulated, fabricated and measured that achieved 4.1 bit/cm2 data density, which is higher than many reported works to date. Therefore, the proposed single sided easily printable tag possesses a good prospect due to its higher encoding capacity and data density, and can replace barcode in item level tagging of low cost and printable items, where tags will be required in trillions.

A novel compact printable dual-polarized (DP) chipless RFID tag is presented in this paper with simulation and measurement results. First, vertically (V) and horizontally (H) polarized ‘U’ shaped slot resonators are etched from two metallic patches to reuse the same frequency band in both V and H polarizations, which doubled the encoding capacity within a fixed bandwidth. Next, slot length variation encoding technique is added to reduce the size of the tag by 50%. After that, a 16-bit proof of concept DP tag is developed that achieved 16 bit/cm2 data density, which is the highest among the reported works to date. Therefore, the proposed single sided easily printable tag possesses a good prospect due to its higher encoding capacity and data density, and can replace barcode in item level tagging of low cost and printable items, where tags will be required in trillions.

A new UHF RFID transponder solution especially designed for tagging batteries of portable devices is presented. The new transponder is a thin and low-cost label that can be read from the opposite side of the tagged object. This feature is based on utilizing the secondary currents induced on the metal object. The new transponder was first analyzed and optimized by electromagnetic simulations, and subsequently a small series of prototypes was fabricated. After finding the right dimensions by electrical measurements, a bigger series with the selected dimensioning was fabricated. With these prototypes a practical test of automatic sorting of batteries was run and the performance of the transponder in practice was evaluated by the yield of the test. In the test, yields of over 96 % were obtained, even though the reader setup was not optimized.

Radio Frequency IDentification (RFID) system is a highly sought-after technology prominently used in the automation, logistics, and supply-chain industries. EPC Gen-2 is the current standard RFID air-interface protocol in the industry. Underlying this standard is the Q-adaptive MAC protocol, which is used to identify and read the tags, by stochastically arranging them over time. The Q-adaptive protocol's performance is sensitive to the number of tags placed under the vicinity of the reader. With the current era of ‘item-level tagging’ witnessing an increased number of tags in a given area; mathematically understanding the performance of the protocol in these large-scale RFID systems becomes essential. Recent works have established the importance of the Q-adaptive protocol, by analyzing its performance with the help of Markov-chain models. However, these analyses suffer from the common ‘state-space explosion’ problem, as the state-space increases quadratically with an increasing number of participating tags. Hence it is essential to come up with a scalable analysis, whose computation model is insensitive to the number of tags. To this end, in this paper, we propose a scalable bound-based solution to study the delay performance of Q-adaptive protocol. We derive the delay bound by exploiting the fact that, in the large number of tags regime, the Q-adaptive protocol rapidly reaches to theoretical maximum performance and stays reasonably close in that optimal region for most of the time. Our extensive simulation results validate our bound-based solution with reasonable accuracy.

Radio Frequency Identification, or RFID, is a technology which has been receiving considerable attention as of late. It is a fairly simple technology involving radio wave communication between a microchip and an electronic reader, in which an identification number stored on the chip is transmitted and processed; it can frequently be found in inventory tracking and access control systems. In this paper, we examine the current uses of RFID, as well as identifying potential future uses of the technology, including item-level tagging, human implants and RFID-chipped passports, while discussing the impacts that each of these uses could potentially have on personal privacy. Possible guidelines for RFID's use, including Fair Information Principles and the RFID Bill of Rights are then presented, as well as technological solutions to personal privacy problems, such as tag killing and blocker tags, as well as simple aluminum foil shields for passports. It is then claimed, though, that guidelines and technological solutions will be ineffective for privacy protection, and that legislation will be necessary to guard against the threats posed by the RFID. Finally, we present what we believe to be the most important legislative points that must be addressed.

A near-field switched loop antenna array with a circular defected ground structure for precise positioning systems is presented. By switching the loop array, the positions of the densely placed small-sized radio frequency identification tags can be identified. The characteristics of the proposed array are verified by the comparisons to the simulated results and experimental measurements.

To detect multiple identifications (IDs) for cm -level high-precision positioning item-level tagging (ILT) systems in near-field ultra-high-frequency RFID applications, an electric-field-coupled multiple ID sensor is presented. The proposed ID sensor consists of four circular electric coupling parts, an impedance-matching network, and an SP4T switch for position control. By switching the electric-field-coupled sensing parts, cm -level position detection of densely aggregated RFID tags for a small-sized ILT can be achieved. The sensing distance of the proposed ID sensor is ~7 mm and its physical size is 50 × 50 mm 2 (~1/7 λ 0 at 920 MHz).

RFID har sedan 80-talet vuxit fram inom industri- och transport-branschen som ett sätt att under-lätta spårning av tillgångar och övervakning av informationsflöden genom logistikkedjan. Tek-nologin har idag många olika applikationsområden och används inom en mängd olika verksam-heter. Item-level Tagging (ILT) är ett sätt att utnyttja tekniken genom att märka enskilda varor för att på så sätt ge dem unika identiteter, vilket erbjuder enorm potential inom detaljhandel. Givet potentialen med tekniken vill vi med vår studie undersöka vilka förutsättningar som kommer att krävas för en ökad användning av ILT och RFID inom detaljhandeln. Detta mål uppnås genom att undersöka de barriärer som tidigare har hindrat en ökad användning samt hur dessa barriärer uppfattas i dagsläget. Efter en grundlig litteraturgenomgång samt intervjuer med respondenter med skilda perspektiv inom området kunde vi dra slutsatsen att det i dagsläget är fyra förutsätt-ningar som behövs för att användningen skall öka; (1) Gemensamma standarder för hur RFID-data skall kodas, (2) Konkurrensmässig press, (3) En ökad kunskap om nyttoeffekter för specifika verksamheter, (4) En ökad kompetens gällande systemlösningar. Since the eighties RFID has been used in industry and logistics as a way to ease tracking of assets and supervising information flows through the logistical chain. Today, the technology can be applied in a number of different ways and is used in a variety of businesses and branches. Item-level Tagging (ILT) is one way to apply the technology by tagging separate items and thus giving them unique identities, which offers enormous potential within retail. Given the technology’s potential our goal with this study is to discover which prerequisites are necessary for an increased use of ILT and RFID in retail. We achieve this goal by studying earlier barriers to adoption and how these barriers are perceived today. A thorough literary review and interviews with respond-ents from differing perspectives within the field enabled us to draw the conclusion that there are four prerequisites that are necessary today for an increased adoption; (1) Common standards for encoding RFID-data, (2) Competitive pressure, (3) Increased knowledge concerning beneficial effects of adoption, (4) Increased know-how concerning system solutions.

In this paper, a novel low cost, compact, printable EM barcode or chipless RFID tag is presented for humidity sensing. The RFID tag sensor is based on planar, single sided resonant scatters operating within the frequency band of 6.5 GHz to 9.5 GHz. Within this frequency range a rectangular patch with a number of slot resonators is designed to designate the data ID. In addition, an electric inductive-capacitive (ELC) resonator is dedicated for humidity sensing. The ELC resonator is modified using polyvinyl- alcohol (PVA) to incorporate humidity sensing. Moreover, the tag sensor can be printed on flexible laminates like plastic and paper for ultra-low cost item level tagging and ubiquitous sensing. The sensor tag has potential of including multiple parameter sensing as the sensing mechanism is independent of data ID generation. It has remarkable application in low cost perishable product process and management.

Intelligent Environments are currently mostly implemented with WSN technologies using conventional connection-based communications. However, connection-based communications may impede progress towards intelligent environments involving massive amounts of sensor nodes. The goal of this paper is to chart a field of more suitable technologies for communication in intelligent environments, which we call collective transmission methods. The idea of collective transmission is to establish communication not between single senders and single receivers but between collectives of senders and receivers, by making use of constructive interference of simultaneously sent signals. We detail how the collective transmission approach can be realized for a concrete application scenario: item-level tagging using printed organic electronics. We describe an algorithm that can be realized on very simple tags. With a testbed implementation, we show that this algorithm can realize robust, collective, approximate read-out of 21 simultaneously sent signals.

In order to streamline the distribution process, the Korean government is currently preparing for a policy that mandates introducing RFID systems to various industrial participants that belong to the supply chain. Different from the industrial products, medical products are subject to a strict regulation on activities such as manufacture, distribution and consumption since it is directly related to people’s life and health. This paper outlines RFID item-level tagging systems, a world first implemented by H pharmaceutical company and demonstrates the strategies based upon its accumulated experience along with the effect of introducing RFID systems.

UHF band passive RFID is an essential identification technology in pervasive computing world. One of the industrial demands to UHF band passive RFID is fast reading of many RF tags. This is particularly relevant for item-level-tagging of CDs, DVDs, books and consumer electronics. Many high-speed MAC protocols have been proposed thus far. Quantitative evaluation of reading speed, however, is not easy because we need to lay out many RF tags and measure the reading durations usually through interrogator APIs, which differ from interrogator to interrogator. In this paper, the authors propose two efficient multiple RF tag emulation algorithms which leverage the probabilistic nature of MAC protocol. We have implemented the algorithms onto a programmable battery assisted passive tag (BAP), equipped with an 8bit micro processor and evaluated the reading speed of commercial interrogators. It was revealed that the BAP can efficiently emulate the behavior of more than 1000 Gen2 RF tags for the reading speed evaluation with a trivial penalty on accuracy.

Item level tagging is a challenge for low cost and passive RFID tags since these are closely packed in the operating environment. Passive tags suffers from poor reading rates using existing RFID interrogators with limited capability on tags and interrogator. In this paper, we have proposed a low cost electronic beamsteering method which enable existing RFID interrogator to be “smarter” by reconfiguring its RF beam adaptively and yet maintain high angular resolution. Little changes to existing transceiver is required to minimize costs since only its external reference clock is enable by direct digital synthesizer (DDS) as a variable reference time delay. The new RFID transceiver system is designed at ISO standards at UHF bands. Experimental results show that it is able to read at least twice as many passive tags, as compared to the conventional beam-switching system.

Radio frequency identification (RFID) is a technology based on the need for remote recognition of objects. It is a fairly simple technology involving radio wave communication between a microchip and an electronic reader, in which information stored on the chip is transmitted and processed. The potential use of this technology includes RFID-chipped passports, human implants, item-level tagging, inventory tracking and access control systems. However, when tags begin to be associated with individuals, privacy is threatened. Good RFID use policies and privacy protecting technologies, while providing a good first step, are not enough to protect individual privacy. RFID is a new type of threat to personal information and must be treated as such; indeed, it must be recognized that existing privacy legislation is not adequate. This paper examines the privacy and ethical issues arising from its use, as well as addressing potential means of handling those issues.

Recent studies claim that RFID transponders containing only an Electronic Product Code (EPC) do not carry person-related data. This paper describes how to use EPCs on RFID transponders to identify individuals and track their consumer habits and locations. In addition, it is shown how these mechanisms can be used to identify social networks. An overview of the relevant legal aspects is given; in particular the article elaborates under what circumstances EPC item level tagging entails the processing of personal data, thus resulting in the applicability of data protection legislation.

Radio Frequency Identi?cation (RFID) is a hot topic in retail supply chain management [Behrenbeck, Kupper et al. 2004]. Yet, a recent study predicts ?that the true bene?ts of RFID for retailers will be in enhanced marketing opportunities? [Sharpless 2005]. Research on RFID for marketing purposes is still rare giving the opportunity for more speci?c research on how RFID will in?uence business to consumer (B2C) marketing and services [Curtin, Kauffman et al. 2005]. Apparel retailing will most likely be one of the ?rst industries to adopt item level tagging and thus bene?t from those new marketing opportunities [Chappell, Durdan et al. 2003; Kurt Salmon Associates 2005]. This paper investigates the opportunities of RFID to enhance B2C marketing of apparel retailers. The paper presents six out of 17 developed RFID applications that support relationship marketing of apparel retailers to better recruit, retain, and recover customers. The RFID applications are classi?ed by the marketing goals they ful?ll and the marketing phase they support. The authors describe the use of each RFID application exempli?ed, and evaluate the additional value for the customer company relationship as well as the feasibility for apparel retailers to implement the application into practice.

In this paper, an overview of near field UHF RFID is presented. This technology recently received attention because of its possible use for item-level tagging where LF/HF RFID has traditionally been used. We review the relevant literature, discuss basic theory of near and far field antenna coupling in application to RFID, and present some experimental measurements.

This paper presents and analyses integrated slot-type tag antennas for passive UHF RFID. Many cardboard packages are nowadays foiled with highly conductive material, and these slot-type tag antennas can be easily integrated into the packages by cutting a slot into the foiled surface of the container. This makes integrated and cost-effective tag antennas possible for container and item-level tagging. In this paper the radiation properties of slot-type tag antennas are modeled with finite element method (FEM) simulation tool and the performance of the tag antennas attached to conductive and liquid-containing packages is verified in practice with read range measurements.