Frequency Radio Frequency Identification Research Articles

Design and Analysis of a Quad-Band Antenna for IoT and Wearable RFID Applications

The role of antennas in wireless communication is critical for enabling efficient signal transmission and reception across various frequency bands, including those associated with IoT (Internet of Things), X-band, S-band, and RFID (radio-frequency identification) systems. This paper presents a small quadruple-band antenna with 25 × 40 × 1.5 mm3 dimensions designed for diverse wireless applications. It is adept at operating in the S-band (2.2 GHz), wireless local area network (WLAN) (5.7 GHz), microwave RFID frequency band (5.8 GHz), and X-band (7.7 GHz and 8.3 GHz). While the majority of existing research focuses on antennas covering two or three bands, our work stands out by achieving quad-band operation in the proposed antenna design. This antenna is constructed on a semiflexible Rogers RT5880 substrate, making it well-suited for wearable applications. Computer Simulation Technology (CST) Microwave studio (2019) simulation package software is chosen for design and analysis. The antenna design features a comb-shaped radiating structure, where each “tooth” is responsible for resonating at a distinct frequency with an appropriate bandwidth. The antenna retains stability in both free space and on-body wearability scenarios. It achieves a low specific absorption rate (SAR), meeting wearable criteria with SAR values below 1.6 W/Kg for all resonating frequencies. The proposed antenna demonstrates suitable radiation efficiency, reaching a maximum of 82.6% and a peak gain of 6.3 dBi. It exhibits a bidirectional pattern in the elevation plane and omnidirectional behavior in the azimuth plane. The antenna finds applications across multiple frequencies and shows close agreement between simulated and measured results, validating its effectiveness.

An optically transparent circularly polarized ultrahigh‐frequency radio frequency identification reader antenna

An optically transparent circularly polarized (CP) radio frequency identification (RFID) antenna is presented in this paper. The RFID antenna consists of a coplanar-fed waveguide inverted L-shaped monopole with a dual feeding structure. The CP wave with a bidirectional radiation pattern is obtained by feeding the radiator at both ends. The transparency of the antenna is obtained by using fluorine tin oxide (FTO) coated soda-lime glass substrate. The proposed antenna operates at a Universal RFID frequency (800–1100 MHz) with circular polarization. The antenna has an impedance bandwidth of 300 MHz and an overlapped 3-dB axial ratio (AR) bandwidth of 110 MHz (860–970 MHz, 12% centered at 915 MHz). It has a peak realized gain of 1.4 dBic. The antenna with the size of 100 × 100 mm2 is designed for ultrahigh-frequency RFID reader applications.

3D Printed Long-Range Cavity Structure UHF RFID Tag Antenna with Painting Conductive Ink on Convex Surface.

In this paper, we describe a long-range convex cavity-type passive ultra-high-frequency (UHF) radio frequency identification (RFID) tag to use on various metal and non-metal surfaces, for IoT sensor energy harvesting. The tag antenna is built on the 3D printed cavity structure with polylactic acid (PLA) plastic and painted with the conductive ink on the 1 mm protruding area (convex) of inner surface and the side-walls of the cavity structure to form a cavity structure. The tag is designed to operate in the UHF band (840–960 MHz). This long-range cavity tag antenna (CTA) works at both 920 MHz and 915 MHz UHF RFID frequencies. It provides a linear polarized (LP) frontal reading range of 35 m and side reading range above 15 m when mounted on either metal or non-metal objects. We describe the antenna characteristics, structure, modeling, simulation, and experimental results. A mathematical reading range also was calculated and compared with experimental data.

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.

Analysis, Design and Implementation of a Fully Integrated Analog Front-End for Microwave RFIDs at 5.8 GHz to Be Used With Compact MIMO Readers

In this paper we present the system and circuit level analysis and feasibility study of applying microwave Radio Frequency Identification (RFID) systems with multipleinput multiple-output (MIMO) reader technology for tracking machining tools in multipath fading conditions of production environments. In the proposed system the MIMO reader interrogates single-antenna tags, and a high RFID frequency of 5.8 GHz is chosen to reduce the size of the reader's antenna array. According to the requirements dictated by the performed system analysis at 5.8 GHz, a low power fully integrated analog frontend (AFE) is designed and fabricated in a standard 65-nm CMOS technology for low power passive transponders. Performance of the Differential Drive Rectifier (DDR) topology as the core of the energy harvesting unit is investigated in detail. A multi-stage DDR power scavenging unit is dimensioned to provide a 1.2 V rectified voltage for 20-30 kQ load range, with a high power conversion efficiency (PCE) for high frequency and low input power level signals. The rectified voltage is then converted to a 1 V regulated voltage for the AFE and the baseband processor with 30 to 50 μW of estimated power consumption. Transistors with standard threshold voltage (VT) have been used for implementation. Measurements of the fabricated multi-stage configuration of the circuit show a maximum PCE of 68.8% at -12.46 dBm, and an input quality factor (Q-factor) of approximately 10. Amplitude-shift keying (ASK) demodulator and backscattering modulator with 80% modulation index, operating according to EPC-C1G2 protocol are applied for data transfer. The AFE consumes less than 1 μW in the reading mode. The AFE tag chip is 0.55 × 0.58 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .

Screen-printed and spray coated graphene-based RFID transponders

We report ultra-high-frequency (UHF, 800 MHz–1 GHz) radio frequency identification (RFID) transponders consisting of printed dipole antennas combined with RFID microchips. These are fabricated on Kapton via screen printing and on paper via spray coating, using inks obtained via microfluidization of graphite. We introduce a hybrid antenna structure, where an Al loop (small compared to the overall size of the antenna) is connected to a microchip with the double function of matching the impedances of antenna and microchip and avoiding bonding between exfoliated graphite and chip. The transponders have reading distance ∼11 m at UHF RFID frequencies, larger than previously reported for graphene-based RFID and comparable with commercial transponders based on metallic antennas.

Glove-Integrated Passive UHF RFID Tags—Fabrication, Testing and Applications

Passive radio-frequency identification (RFID) technology enables versatile energy- and cost-efficient wireless platforms. We present passive ultra-high frequency (UHF) RFID tags integrated into normal work gloves for wearable RFID applications. The tags were designed to be functional throughout the global UHF RFID frequency range. The use environments of work gloves are challenging, for example due to moisture and mechanical stresses, which means the glove-integrated solutions have unique reliability issues to consider. We introduce 3-D printing of a flexible thermoplastic material directly onto the glove and embed electro-textile antennas and RFID microchip components inside the 3-D-printed structure. This manufacturing method solves the above-mentioned reliability challenges and enables the practical use of glove-integrated passive RFID tags. The performance of the fabricated glove-tags is first evaluated on a male test subject in an EMC room and in an office environment. Based on the wireless measurement results, the read ranges of the glove-tags are around 2–3 m throughout the frequency range of 800–1000 MHz. These results meet the requirements of many practical applications of glove-tags. Further, these glove-tags are found to endure extreme moisture and mechanical stresses, which supports their use in versatile use environments. Finally, the developed glove-tags are successfully tested in actual use situations for identification and access control. These results are very promising, especially considering the cost-effectiveness and the easiness of tag integration into different types of gloves.

The Localization of Buried Objects in the Soil Using an RFID Tag: Protocol Description and Parameter Estimation With the Model of the Oscillating Magnetic Field in Media

This paper introduces a localization protocol that fills a gap among already existing methods, such as ground penetrating radar or methods based on inductive prospecting. The principle is to attach a radio frequency identification (RFID) tag to a non-metallic object of interest buried in a non-magnetic soil and deduce its depth from the magnetic induction in the near field regime between the buried tag and an RFID antenna. Electromagnetic propagation in soils has been extensively studied in geophysics. The higher the frequency, the lower the penetration depth. The standard frequency range in geophysics is lower than 100 kHz to reach penetration depth as high as several tens of meters and the soil conductance is the main influencing factor. When working with passive RFID tags, their received power and, consequently, the detection range in air grows with the frequency. A frequency tradeoff for the detection in media lies in the range of 10–50 MHz, where the authorized RFID frequency is 13.56 MHZ. In this range, the wavenumber in weakly saline soils depends essentially on the medium dielectric permittivity (see Appendix A ). In this paper, we calculate the precision of the estimation of the burying depth of the tag in terms of the standard deviation and the corresponding bias up to two uncertain parameters—the penetration depth and the activation field. The laboratory experiments provide results supporting the chosen model.

On phase-based localization with narrowband backscatter signals

Backscatter communication is widely adopted for radio-frequency identification (RFID). Recently, the possibility of localizing passive tags or readers, exploiting phase measurements from backscatter signals, received large attention. In particular, several applications with standard ultra-high frequency (UHF) RFID were proposed, thanks to the availability of the phase information in many commercial readers, without requiring any hardware modification. In this paper, the problem of localizing a tag or a reader using phase measurements is addressed from the estimation theory point of view. The derived structure for the maximum likelihood estimator is compared with other approaches proposed in the literature, showing its enhanced performance in a typical application context.

Ultrahigh Radio Frequency (820-960 MHz) Identification System Affects Antioxidant Barrier in Red Blood Cell Concentrates

Background and objectives: Radio frequency identification (RFID) tags have advantages over bar codes in blood management system. Ultra-high frequency (UHF) RFID technology (820-960 MHz) in many ways has more advantages than high frequency (HF) RFID (13.56 MHz). The aim of our study was the evaluation of the effects of UHF RFID in comparison to HF RFID radiation on quality markers of RBC and on the oxidoreductive balance in RBC stored in containers labelled with RFID tags. Materials and methods: Ten RBC units were split into three components, one control unit-marked with bar code and two test units labeled with RFID tags - one operating on UHF and the second on HF radio waves. All units were stored at 2-6°C for 35 days. The test groups were exposed to radio waves continuously during storage. The quality parameters as well as concentration of malondialdehyde (MDA), and activities of superoxide dismutase, glutathione peroxidase and glutathione reductase were measured. Results: The degree of hemolysis and the concentration of K+ were statistically significant higher on 35th day of storage in RBC labelled with UHF RFID tags compare to control and HF RFID groups. On the 35th day of storage the concentration of MDA was statistically significant higher and the activities of oxidoreductive enzymes were statistically significant lower in the UHF group compare to control and HF groups. Conclusion: UHF RFID tags affect oxidoreductive balance in RBC and may lead to eryptosis. The approval of UHF RFID system for blood components needs further studies.

Compact Dual Band Monopole Antenna for RFID and WLAN Applications

A compact dual band monopole antenna for application in portable devices covering wireless local area network (WLAN) and radio frequency identification (RFID) technologies at 2.4 and 5.0 GHz is presented in our paper. The antenna is fabricated on a relatively inexpensive dielectric material. The dimensions of FR4 substrate used is 38 x 30 x 1.6 mm3. Experimental results provide omnidirectional radiation patterns, which is in agreement with requirement of both frequency bands. We obtain resonant frequencies of 2.45 and 5.20 GHz from the fabricated antenna. The proposed antenna is simple in design, compact in size and exhibits broadband impedance matching, appropriate gain characteristics (>2.5 dBi) and consistent omnidirectional radiation patterns in the RFID and WLAN frequency regions. All simulations have been carried out on HFSS ver. 15.0.

A wirelessly powered RFID-based smart contact lens system

This paper presents a wireless smart contact lens system, comprising a capacitive sensor interface circuitry and a wirelessly powered radio frequency identification (RFID)-compatible system, for sensor control and data communication. To improve compliance and reduce user discomfort, the capacitive sensor was embedded on a 200-μm-thick soft contact lens using commercially available biocompatible lens material and a standard sandwich manufacturing process. The proposed lens can communicate with RFID equipment at an ultra-high frequency (UHF) RFID frequency of 920 MHz. A successful communication distance of 2 cm was achieved under 18 dBm incident radio frequency (RF) power, and a maximum distance of 4 cm was achieved under 28 dBm incident power. The uniform magnetic field distribution of the transmitting antenna enhances energy transmission and provides robust operation against shifts in relative location and misalignment of the contact lens and the glass caused by eye movement and blinking.

Influence of Temperature on the Dynamic Reading Performance of UHF RFID System: Theory and Experimentation

Abstract The radio frequency identification (RFID) system is vulnerable to a variety of factors (metal, liquid, temperature, and so on) in the practical application. In this paper, the reading distance of tags, as the evaluation criteria for the reading performance of the RFID system, is focused on to study the influence of environmental temperature on the dynamical performance of an ultra-high frequency (UHF) RFID system. An experimentation system, including temperature control system and detection platform, is devised to control temperature and measure the reading distance of the RFID tag. According to the experimental data of the tag's reading distance at different temperature, a fitting model between temperature and tag's reading distance is established. Experimental results show that the tag's reading distance decreases with the increase of temperature. Finally, the corresponding temperature compensation mechanism is deduced to get the reading distance under the same reference temperature. This paper provides an effective method for selection and evaluation of UHF RFID tags at different temperature.

New IoT proximity service based heterogeneous RFID readers collision control

Purpose Internet of Things’ (IoT’s) first wave started with tracking services for better inventory management mainly using radio frequency identification (RFID) technology. Later on, monitoring services became one of the major interests, including sensing technologies, and then more actuation for remote control-type of IoT applications such as smart homes, smart cities and Industry 4.0. In this paper, the authors focus on the RFID technology impairment. They propose to take advantage of the mature IoT technologies that offer native service discovery such as blutooth or LTE D2D ProSe or Wifi Direct. Using the automatic service discovery in the new framework will make heterogeneous readers aware of the presence of other readers and this will be used by the proposed distributed algorithm to better control the multiple RFID reader interference problem. The author clearly considers emerging Industry 4.0 use case, where RFID technology is of major interest for both identification and tracking. To enhance the RFID tag reading performance, collisions in the RFID frequency should be minimized with reader-to-reader coordination protocols. In this paper, the author proposes a simple distributed reader anti-collision protocol named DiSim that makes use of proximity services of IoT network and is compliant with the current RFID standards. The author evaluates the efficiency of the proposal via simulation. Design/methodology/approach In this paper, the author proposes a simple distributed reader anti-collision protocol named DiSim that makes use of proximity services of IoT network and is compliant with the current RFID standards. The author evaluates the efficiency of the proposal via simulation to study its behavior in very dense and heterogeneous RFID environments. Specifically, the author explores the coexistence of powerful static readers and small mobile readers, comparing the proposal with a standard ETSI CSMA method. The proposal reduces significantly the number of access attempts, which are resource-expensive for the readers. The results show that the objectives of DiSim are met, producing low reader collision probability and, however, having lower average readings per reader per time. Findings DiSim is evaluated with the ETSI standard LBT protocol for multi-reader environments in several environments with varied levels of reader and tag densities, having both static powerful RFID readers and heterogeneous randomly moving mobile RFID readers. It effectively reduces the number of backoffs or contentions for the RFID channel. This has high reading success rate due to the avoided collisions; however, the readers are put to wait, and DiSim has less average readings per reader per time. As an additional side evaluation, the ETSI standard LBT mechanism was found to present a good performance for low-density mid-coverage scenarios, however, with high variability on the evaluation results. Research limitations/implications To show more results, the author needs to do real experimentation in a warehouse, such as Amazon warehouse, where he expects to have more and more robots, start shelves, automatic item finding on the shelve, etc. Practical implications Future work considers experimentation in a real warehouse equipped with heterogeneous RFID readers and real-time analysis of RFID reading efficiency also combined with indoor localization and navigation for warehouse mobile robots. Social implications More automatization is expected in the future; this work makes the use of RFID technology more efficient and opens more possibilities for services deployment in different domains such as the industry which was considered not only in this paper but also in smart cites and smart homes. Originality/value Compared to the literature, the proposal offers the advantage to not be dependent on a centralized server controlling the RFID readers. It also offers the possibility for an existing RFID architecture to add new readers from a different manufacturer, as the readers using the approach will have the possibility to discover the capabilities of the new interaction other RFID readers. This solution takes advantage of the available proximity service that will be more and more offered by the IoT technologies.

CPW-fed Circularly Polarized Slot Antenna with Small Gap and Stick-shaped Shorted Strip for UHF FRID Readers

Abstract A new circularly polarized (CP) slot antenna with a small gap and a stick-shaped shorted strip is presented. The proposed antenna has a sufficient bandwidth for ultrahigh frequency (UHF) radio-frequency identification (RFID) reader applications. The antenna structure consists of a rectangular slot with a small gap, a stick-shaped shorted strip and a 50 Ω coplanar waveguide (CPW) feedline with an asymmetrical ground plane. By using the stick -shaped shorted strip to disturb magnetic current distribution on the slot, the CP radiation can be generated. The measured results demonstrate that the proposed antenna can reach a 10 dB return loss impedance bandwidth of 14.1 % (894–1030 MHz) and a 3 dB axial ratio (AR) bandwidth of 6.4 % (910–970 MHz). The whole antenna size is 80 × 80 × 1.6 mm3.

Compact design of UHF RFID and NFC antennas for mobile phones

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 low-profile 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.

CPW-Fed Wideband Circular Polarized Antenna for UHF RFID Applications

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.

A miniature tri-band RFID reader antenna with high gain for portable devices

This paper presents a miniature monopole reader antenna for tri-band radio frequency identification (RFID) portable devices. The proposed antenna operates at the main RFID frequencies and can alleviate and compensate for the shortcomings of a single-band antenna. An additional rectangular stub couples with the bent monopole antenna, allowing the latter to resonate at the RFID bands at 902–928 MHz, 2.4–2.48 GHz, and 5.725–5.875 GHz. By bending the feedline, the dimensions of the miniature antenna are reduced to 115.5 × 20 × 1.6 mm3, facilitating its integration into portable devices. The measured bandwidths(return loss &lt; −10 dB) of the proposed antenna are 677, 580, and 250 MHz in the three operating bands, 883–1560 MHz, 2.31–2.89 GHz, and 5.65–5.9 GHz, respectively, with high-gain characteristics. An experimental study of a fabricated prototype of the optimized antenna is performed, and the results verify its good performance.

Online Measurement of Alcohol Concentration Based on Radio-Frequency Identification

Abstract This paper presents a method for online measuring signal backscattering and reading distance from radio frequency identification (RFID) tags attached to the surface of the liquid, and for calculating the corresponding alcohol concentration. We derive a theoretical formula on the reading distance and received power. Subsequently, the former measurement values are converted to the corresponding alcohol concentration. Experiments are performed using an ISO/IEC 18046-based measurement system in the ultra high frequency (UHF) RFID band [ISO/IEC 18046, “Information Technology—Radio Frequency Identification Device Performance Test Methods,” International Organization for Standardization, London, 2007]. A fitted model of the relationship of alcohol concentration, reading distances, and received power is established. Based on the proposed fitted model, the processor can calculate alcohol concentration in aqueous solutions. The experimental data are compliant to the theoretical counterparts. This online method could be applied to dynamic measurement in automatic assembly line and has the advantages of excellent versatility, high measuring accuracy, stable performance, and quick response speed.

An RFID model for improving workers’ safety at the seaport in transitional environment

The paper proposes a Radio Frequency IDentification (RFID) model for enhancing port workers’ safety with reference to the Port of Bar (Montenegro) as a developing seaport operating in a transitional environment. The paper also highlights the lack of appropriate Information and Communication Technology (ICT) solutions in some developing seaports, including safety-related ones. It emphasizes the importance of safety measures through the prism of reducing the number of accidents, and gives a review of some RFID safety solutions in the harsh environments. The main part of the paper deals with the RFID worker’s safety model proposed according to the Port of Bar’s individual needs. The model has been presented at a logic level, while some of the physical and link layers performances between the set of an active and several passive RFID devices embedded to the port workers’ Personal Protective Equipment (PPE) and the Ultra High Frequency (UHF) RFID readers located at the port perimeter, are simulated in Matlab and OMNeT++. The obtained results followed by discussions can be used as landmarks to the ports’ management in adapting this or a similar model for enhancing safety measures in the port and its promoting as a safety one at the maritime market.