Radio Frequency Identification Antenna Research Articles

Compact dual‐band fractal hexagonal ring monopole antenna for RFID and GSM applications

AbstractA novel compact dual‐band fractal antenna suitable for radio frequency identification (RFID) and GSM 1800 applications is developed and presented in this paper. This is achieved by adequate combination of three slotted hexagonal fractal rings which resulted in a significantly reduced size structure that can operate in the frequency ranges [0.895‐0.962 GHz] and [1.706‐1.856 GHz] that cover the frequency bands allocated to the intended applications. The proposed antenna has been fabricated and its reflection coefficient measured where a good agreement is observed with the simulated results.

Localizing Missing Entities Using Parked Vehicles: An RFID-Based System

In this paper, we demonstrate a system for locating missing entities using radio-frequency identification (RFID)-based techniques. A key feature of our system is that we utilize the large, high-density networks of parked vehicles incident to urban areas for the detection and reporting process. RFID readers and antennas are placed within the vehicles, while RFID passive tags are carried on the entity of interest via some means, e.g., a wrist band. If an entity is reported as missing, then the application on board each of the parked vehicles is awoken by an administrative center. The technology on board the vehicles enables those participating in the service to attempt to locate the missing entity, sending useful information back to the administration center, which could be tied to an organization like the police. We demonstrate our system via a use case of a missing Alzheimer’s patient in inner-city Dublin, Ireland. One of the key challenges in validating our system is being able to replicate a large-scale, real-world setting. Our technique for obtaining an early evaluation of our system thus employs the use of the microscopic traffic simulation package Simulation of Urban MObility (SUMO). SUMO permits multiple emulations of hundreds or thousands of parked vehicles participating in the service to be carried out, while simulated pedestrians walk random routes. Our results show that a simulated wandering person in need can be detected within a 30-min time frame, in the heart of Dublin city center, during a typical weekday, up to approximately 98% of the time, depending on how various parameters of the system are set.

The Closed-Form Solution of Frequency Shift for an HF RFID Coil Antenna in Metallic Environments

The performance of a high frequency radio frequency identification (RFID) coil antenna is strongly dependent on its operating environments. The presence of the metallic environments can shift up the resonant frequency of the antenna and change its field intensity. This paper presents a novel equivalent model based on image theory to study quantitatively the proximity effects of metallic environments on the antenna. From the proposed model an equivalent circuit has been extracted, and it is used to derive the frequency shift formulas of the antenna based on the theory of magnetic resonant coupling. Then the closed-form solution of operating frequency for the antenna in metallic environments can be obtained in terms of the geometric parameters of coil antenna as well as the distance between the coil antenna and the metal plate using the proposed formulas. To confirm the validity of the proposed model, simulations have been carried out and compared with the measurement results. The results show that the proposed model can predict the operating frequency of the antenna in metallic environments and the distribution of magnetic field accurately and rapidly. The closed-form solution of frequency shift derived from this paper can be helpful to engineers to enhance the RFID antennas performance by alleviating the effects of metallic environments, which is pivotal for the Internet of Things technology.

RFID Antennas for Body-Area Applications: From Wearables to Implants

Radio-frequency identification (RFID) technology has recently attracted significant interest in the realm of body-area applications, including both wearables and implants. The presence of the human body in close proximity to the RFID device creates several challenges in terms of design, fabrication, and testing, while also ushering in a whole new realm of opportunities for health care and other body-area applications. With these factors in mind, this article provides a holistic and critical review of design challenges associated with body-area RFID technologies, including operation frequencies, influence of the surrounding biological tissues, antenna design and miniaturization, and conformance to international safety guidelines. Concurrently, a number of fabrication methods are discussed for realizing flexible, conformal, and robust RFID device prototypes. The article concludes by reviewing transformative RFID-based solutions for wearable and implantable applications and discussing the future opportunities and challenges raised. Notably, this is the first time that a comprehensive review has been presented in the area of RFID antennas for body-area applications, addressing challenges specific to on-/in-body RFID operation and spanning a wide range of aspects that include design, fabrication, testing, and, eventually, applications and future directions. As such, the utmost aim of this article is to be a unique point of reference for experts and nonexperts in the field.

Antenna Array Synthesis for RFID-Based Electronic Toll Collection

This paper deals with the synthesis and design of reader antenna for radio-frequency identification (RFID)-based dedicated short-range communication (DSRC) systems. A method for synthesizing a planar antenna array with both the aim of stretching the communication area toward the longitudinal direction and confining it within a certain number of road lanes is described. This method can be used for any working frequency, and two synthesis examples are described taking into account requirements and system parameters of the standards electronic product code (EPC) Gen2 in the ultrahigh frequency (UHF) band, European ETSI EN 302 663 for intelligent transportation system/DSRC, and Chinese GB/T20851-2007 for electronic toll collection/DSRC at 5.8 GHz. After that, the design of a specific 4 × 4 planar antenna array for the case of a UHF EPC Gen2 Chinese band 920.5-924.5 MHz is reported. Microstrip technology is chosen for its advantages of being light, simple, inexpensive, and easy to manufacture. The proposed design presents good matching characteristic and bandwidth, and effectively synthesizes the required communication area (also in the presence of an external radome). Measurement results performed in an anechoic environment together with the experimental verification of the synthesized communication area confirm the validity of the proposed method.

Feature Extraction for Robust Crack Monitoring Using Passive Wireless RFID Antenna Sensors

Radio-frequency identification (RFID) tag antenna-based passive wireless sensors are receiving increasing attentions for structural health monitoring in large-scale infrastructure. For permanently installed monitoring, robustness to measurement variation including environmental conditions is a practical issue. This paper retrospects the communication principle of magnetic resonant coupling for low-frequency passive wireless RFID antenna sensors. The influence of communication is uncovered and essentially separated from sensing through two steps: sweep (source) frequency to capture the system behavior, i.e., a resonance frequency range, and multiple feature extraction, fusion, and selection in conjunction with normalization for the selected time-domain feature of peak-to-peak. By this way, the robustness of the low-cost RFID sensing system is enhanced. The proposed method is validated by the case study in open crack detection and characterization under varied measurement conditions.

Wireless Passive Ultra High Frequency RFID Antenna Sensor for Surface Crack Monitoring and Quantitative Analysis.

An exponential increase in large-scale infrastructure facilitates the development of wireless passive sensors for permanent installation and in-service health monitoring. Due to their wireless, passive and cost-effective characteristics, ultra-high frequency (UHF) radio frequency identification (RFID) tag antenna based sensors are receiving increasing attention for structural health monitoring (SHM). This paper uses a circular patch antenna sensor with an open rectangular window for crack monitoring. The sensing mechanism is quantitatively studied in conjunction with a mode analysis, which can uncover the intrinsic principle for turning an antenna into a crack sensor. The robustness of the feature is examined when the variation of crack position associated with an aluminum sample and the antenna sensor is considered. The experimental results demonstrate a reasonable sensitivity and resolution for crack characterization.

UHF RFID system for wirelessly detection of corrosion based on resonance frequency shift in forward interrogation power

A radio frequency identification (RFID) based system is developed in this paper as a novel passive wireless sensor to detect corrosion for structural health monitoring (SHM) of metallic surface through simulation, design, fabrication and experiment. Firstly, a 2D label-type antenna in a new configuration – circular three arm (CTA) element – is designed as an ultrahigh frequency (UHF) RFID sensor tag working on surface of steel samples. To improve gain and power transmission coefficient, a parasitic element has been added into the centre of CTA. The CTA antenna attached with the parasitic element – so called (CTAP) sensor – has a quality factor notably higher than similar metal mountable UHF RFID antennas that has been resulted to revelation of resonance frequency in measured forward interrogation power. A demonstration and validation system are introduced then to detect corrosion based on the shift of revealed resonance frequency in the forward interrogation power to activate the CTAP tag when placed on surface of corroded and non-corroded steel samples. Results show that the presented system could communicate with sensor tag to detect corrosion up to 2 m of read monitoring range at the UHF RFID standard bandwidth with a sensitivity around of 13 MHz.

Improving the <inline-formula> <tex-math notation="LaTeX">${Q}$ </tex-math> </inline-formula>-Factor of Printed HF RFID Loop Antennas on Flexible Substrates by Condensing the Microstructures of Conductors

High frequency (HF) radio frequency identification (RFID) loop antennas are popular for HF RFID, energy transfer and near field communication applications. One of the major parameters defining the working range of HF RFID antennas is their ${Q}$ -factor. Printing techniques are the ideal method for mass fabrication of HF RFID loop antennas. However, due to the relatively low conductivity of the inks available on the market, the ${Q}$ -factor of the printed HF loop antenna tends to be low and in many cases, fails to meet the working range requirements. This paper reports two methods to condense the microstructures of the conductors in order to improve the ${Q}$ -factors of printed HF RFID loop antennas. Both thermal compression (pressing the sample at elevated temperature) and near-infrared annealing are studied, and the results have demonstrated that both approaches are efficient in improving the ${Q}$ -factors of printed loop antennas.

Inkjet Printing of Epidermal RFID Antennas by Self-Sintering Conductive Ink

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.

A Dipole RFID Antenna at UHF Band Design Optimization

Radio frequency identification (RFID) tags is widely used in all walks of life. Ultra high frequency shows good performance in the field of logistics, transportation management, animal tracking, etc. In this paper, by studying the antenna model, it is found that the thickness of the substrate has a great influence on the impedance of the antenna, which directly affects the performance of the antenna.

Compact dual band slotted triangular monopole antenna for RFID applications

AbstractThis paper presents a compact monopole antenna for radio frequency identification (RFID) systems. The proposed antenna is a dual band structure that can operate in the frequency ranges [0.797–1.004 GHz] and [2.234–2.934 GHz]. Consequently, the antenna covers widely the two UHF bands dedicated for RFID applications which are [0.860–0.960 GHz] and [2.380–2.520 GHz]. Moreover, the antenna is compact and its wide band nature makes it suitable for several applications other than RFID (GSM, UMTS, Wi‐Fi, Bluetooth, etc.). The proposed antenna has been fabricated and its reflection coefficient measured where a good agreement is observed with the simulated results.

A passive RFID tag-based locating and navigating approach for automated guided vehicle

Abstract This research is motivated by the industrial applications of Cyber-physical System (CPS) such as smart warehouse and intelligent manufacturing which require the support of AGV (Automated Guided Vehicle). One of the key research is locating and navigating approach that should be with much flexibility for dealing with complex industrial applications. This paper takes a passive radio frequency identification (RFID) tag-based locating and navigating approach for AGV to examine the influences of tags, antennas, and environmental aspects. The approach was validated and a prototype system was built up. Several key observations are significant from the implementation and simulation study. Firstly, it is observed that adding angle reflector could eliminate the back lobe and restrain backward reflection. Secondly, RFID antenna center and the tag center should be designed at the same height could reduce the impact area of reflection. Lessons and insights from this study will be significant for industrial practitioners to implement AGVs in smart warehouse and manufacturing management.

A RFID-based wireless NH<SUB align="right">3 gas detector using spin coated carbon nanotubes as sensitive layer

A radio frequency identification (RFID)-based wireless ammonia (NH3) gas detector was developed to work at 868 MHz. Using carbon nanotubes (CNT) thin film as a sensitive layer, a standard RFID tag is transformed into an RFID gas detector. First, RFID copper antenna on flexible polyethylene terephthalate (PET) substrate was fabricated by combining inkjet printing and copper electroplating. After that, CNT thin film was deposited on RFID antenna by spin coating method. RFID chip AK3 tagsys loop was attached with RFID antenna to form RFID tag. Performance of this gas detector was tested by measuring impedance of the RFID antenna and read-range of the RFID tag before and after being submitted to NH3 gas. The impedance of CNT thin film changed in presence of ammonia, leading to a decrease of the RFID tag read-range. A low-cost passive RFID gas detector is demonstrated with good response to NH3 gas down to 10 ppm, the RFID tag read-range was decreased from 2.5 m to 1.9 m. Besides, the impedance of RFID antenna had shown the good change, from 11.70 – j20.70 to 8.56 – j33.45 after being exposed 1 min to NH3 gas. From this result, this wireless gas detector is promising to be applied in real life to detect gas leakage, especially in relatively harsh and non-light-of-sight environments, because of many advantages such as low-cost, wireless and easy to control.

Tunable Platform Tolerant Antenna Design for RFID and IoT Applications Using Characteristic Mode Analysis

Radio frequency identification (RFID) is a key technology to realize IoT (Internet of Things) dreams. RFID technology has been emerging in sensing, identification, tracking, and localization of goods. In order to tag a huge number of things, it is cost‐effective to use one RFID antenna for tagging different things. Therefore, in this paper a platform tolerant RFID tag antenna with tunable capability is proposed. The proposed tag antenna is designed and optimized using characteristic mode analysis (CMA). Moreover, this tag antenna consists of a folded patch wrapped around FR 4 substrate and a feeding loop element printed on a paper substrate. The inductive feeding loop is stacked over folded patch and it provides impedance match with RFID chip. Because of separate radiating and feeding element, this tag antenna has a versatility of impedance matching with any RFID chip. Furthermore, this tag is able to cover American RFID band (902–928 MHz) and can be tuned to European RFID band (865–868 MHz) by adding tunable strips. In order to demonstrate platform tolerant operation, the read range of RFID tag is measured by mounting it on different materials. The maximum read range of RFID tag is 4.5 m in free space or on dielectrics and 6.5 m above 200 × 200 mm2 metal plate, respectively.

Design and Simulation of a Rectangular E-Shaped Microstrip Patch Antenna for RFID based Intelligent Transportation

A low profile, rectangular E-shaped microstrip patch antenna is designed and proposed for radio-frequency identification (RFID) based intelligent transportation system (ITS) in this paper. The proposed antenna design aims to achieve high gain and low return loss at 0.96 GHz as it is suitable for ultra-high frequency (UHF) RFID tags. The proposed antenna composed of a radiating patch on one side of the dielectric substrate and the ground plane on the other side, copper is used to produce the main radiator. The simulation of the proposed antenna is performed employing the high-frequency structure simulator (HFSS). The dielectric substrate used for the suggested antenna is an FR4 substrate with dielectric constant of 4.3 and height 1.5 mm. The performance of the proposed antenna is measured in terms of gain, return loss, voltage standing wave ratio (VSWR), radiation pattern and the bandwidth. The antenna gain and the return loss of the suggested antenna at 0.96 GHz are 7.3 dB and -12.43 dB, respectively.

A broadband circularly polarized antenna of square-ring patch for UHF RFID reader applications

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 mm3. 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.

Design of Wearable Radio Frequency Identification Antenna

This paper focuses on the development of a wearable radio frequency identification (RFID) antenna to be embedded on shirt collars or cuffs. Wearable RFID tags tend to be conformal, and are required to reasonably meet design specifications even when under deformation. A simple circular dipole structure was selected as the base design for the antenna. Operating in the ultra-high frequency band at 866 MHz and over an operating range of around 5 m, the antenna is versatile enough to be used for a number of applications such as the tagging of patients in a hospital or for workers on dangerous construction sites. The designs presented account for the complex input impedance generally observed in RFID systems and the final design employs an intricate spiral structure to accommodate longer wavelengths. This resulted in a compact portable antenna able to meet device specifications.

Real-time detection system for tumor localization during minimally invasive surgery for gastric and colon cancer removal: In vivo feasibility study in a swine model.

During minimally invasive surgery (MIS), it is impossible to directly detect marked clips around tumors via palpation. Therefore, we developed a novel method and device using Radio Frequency IDentification (RFID) technology to detect the position of clips during minimally invasive gastrectomy or colectomy. The feasibility of the RFID-based detection system was evaluated in an animal experiment consisting of seven swine. The primary outcome was to successfully detect the location of RFID clips in the stomach and colon. The secondary outcome measures were to detect time (time during the intracorporeal detection of the RFID clip), and accuracy (distance between the RFID clip and the detected site). A total of 25 detection attempts (14 in the stomach and 11 in the colon) using the RFID antenna had a 100% success rate. The median detection time was 32.5 s (range, 15-119 s) for the stomach and 28.0 s (range, 8-87 s) for the colon. The median detection distance was 6.5 mm (range, 4-18 mm) for the stomach and 6.0 mm (range, 3-13 mm) for the colon. We demonstrated favorable results for a RFID system that detects the position of gastric and colon tumors in real-time during MIS.

A novel miniaturized log-periodic dipole array antenna using dynamic scaling factor for RFID application

A novel radio frequency identification antenna based on log-periodic dipole array (LPDA) antenna at 5.8 GHz is presented. The antenna design approach consists of two major steps. Firstly, the conventional primitive method is used to design a traditional LPDA antenna. The antenna structure is then miniaturized and its overall performance significantly improved. Dynamic scaling factor along with uniformly separated elements are introduced in this class of antenna, resulting in a 51.5% length reduction. To improve front-to-back (F/B) ratio a symmetrical folding technique is employed, leading to 21.5 dB F/B ratio for the fabricated prototype. An excellent level of input impedance matching (S11 = −28 dB) is achieved using a well-designed feeding system through a proximity coupling technique. The measured gain of the fabricated prototype is 6.2 dBi, and the overall dimension of the antenna substrate is only 30 × 45 mm2 (0.58λ0 × 0.87λ0).