Radio Frequency Identification Tag Design Research Articles

Efficiency Improvement for Chipless RFID Tag Design Using Frequency Placement and Taguchi-Based Initialized PSO.

Frequency encoding chipless Radio Frequency Identification (RFID) tags have been frequently using the radar cross section (RCS) parameter to determine the resonant frequencies corresponding to the encoded information. Recent advancements in chipless RFID design have focused on the generation of multiple frequencies without considering the frequency position and signal amplitude. This article proposes a novel method for chipless RFID tag design, in which the RCS response can be located at an exact position, corresponding to the desired encoding signal spectrum. To achieve this, the empirical Taguchi method (TM), in combination with particle swarm optimization (PSO), is used to automatically search for optimal design parameters for chipless RFID tags with a fast response time, to comply with the frequency encoding requirements in the presence of the mutual coupling effect. The proposed design method is validated using I-slotted chipless tag structures that are fabricated and measured with different sets of resonant frequencies.

Loop-Coupled Small Antenna With Enhanced Bandwidth for On-Metal UHF RFID Tag Design

A small antenna with a dimension of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$36\times 39\times1.5$ </tex-math></inline-formula> mm ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.109\lambda \times 0.118\lambda \times 0.0045\lambda $ </tex-math></inline-formula> ) is proposed for wideband metal-mountable applications. An excitation loop is designed within the antenna structure for achieving good energy coupling from the loop to the outer patch. With the introduction of a narrow stub, connecting the top and bottom conductors, the 3 dB impedance bandwidth of the proposed tag can be enhanced from 16 to 50 MHz, without modifying other design parameters. The bandwidth and the impedance matching between the antenna and the microchip can be tuned by varying the stub width. The gap separation between the top patches and the L-slot on the patch can also be adjusted for bandwidth optimization. The tag is readable from at least 6 m within 896–917 MHz, regardless of the metal plate dimension (12–24 cm). The tag is also readable from at a minimum of 4 m within a wide frequency range of 887–927 MHz, covering the entire US UHF radio frequency identification (RFID) band when attached to different sizes of metallic items.

A Zeroth-Order Slot-Loaded Cap-Shaped Patch Antenna With Omnidirectional Radiation Characteristic for UHF RFID Tag Design

The zeroth-order resonance of a compact patch structure is explored for designing a metal-mountable tag antenna in the United States (US) ultrahigh-frequency (UHF) radio frequency identification (RFID) passband. This zeroth-order resonator (ZOR) structure comprises a cap-shaped patch loaded with two L-shaped slots. Also, the patch is coupled to the ground through two inductive stubs which provide enough parasitic reactance to support the zeroth-order resonance. The proposed single-element ZOR can generate sufficient antenna impedance for achieving a conjugate match with the RFID chip impedance. Good omnidirectional radiation characteristic with vertically polarized fields can be attained in the azimuth plane when the tag antenna is placed on a metallic surface. The proposed tag antenna’s realized gain at 915 MHz is −1.382 dB [effective isotropic radiated power (EIRP) 4 W]. A stable read distance of ~15 m is obtainable with even spatial coverage in the entire azimuth plane. The resonance frequency of the proposed tag does not vary much with the object being tagged.

Robust RFID tag design for reliable communication within the Internet of Things

Radio frequency identification (RFID) is a cost-effective method to support the Industrial Internet of Things (IIoT) and is an enabling technology for Industry 5.0. The use of RFID is particularly suited to IIoT as it does not require a line of sight for communication and can be retroactively affixed to non-smart items. However, RFID communication is affected by the properties of the material the tag is affixed to, specifically the material permittivity. Metal is commonly present in smart factory environments and supply chains and impedes RFID communication. A suitable tag design is required to accommodate these challenges and ensure resilience for Industry 5.0 applications. The research presented in this paper has assessed the communication performance of RFID antenna designs with and without metal present beneath the tag. The RFID tag designs that performed reliably in the simulation were manufactured, and their read range was tested on materials of varying relative permittivity and thickness to represent MP and NMP scenarios. The results have verified the robustness of “Cyber” to “Physical” designs and provide recommendations to support practitioner IIoT tag selection.

Analysis on Polarization Responses of Resonators for Frequency-Coded Chipless RFID Tags

This article presents a method to analyze co- and cross-polarized responses of the resonators exploited in the development of frequency-coded chipless radio frequency identification (RFID) tags. The method uses the complex radar cross Section (RCS) matrix to characterize the polarization of the scattered response of resonators. Four different symmetry states are introduced, and all resonators are classified under each category based on their structures. Then, the complex RCS matrix is obtained for each group. Then, four different resonators, each representing the respective symmetry state, are simulated and measured to validate the theory. To highlight the advantages of the presented method, two significant applications of the method are investigated. The presented theory is used in the first application to determine resonator structures for designing orientation independent cross-polarized tags. The proposed technique not only accelerates the design of frequency-coded chipless RFID tags but also helps figure out proper geometry for resonators with cross-polarized responses with minimum amplitude deviation at different azimuth plane orientation angles. In the latter application, we predict co- and cross-polarized responses of a tag at arbitrary orientation angles, using one initial measurement. This prediction provides a thorough insight into the co- and cross-polarized responses of tags at different orientation angles.

Ultra slim and small UHF RFID tag design for mounting on curved surfaces

This paper proposes a UHF flexible passive tag antenna for Radio Frequency Identification (RFID) which operates at 902–928 MHz frequency band. As main contribution, we design an electrically small and slim tag antenna by using a flexible commercial substrate. The small antenna has dimensions of 13 mm × 28 mm × 0.35 mm. The geometry of the tag antenna was optimized, using a Genetic Algorithm, to maximize its read range. The antenna performance was evaluated on flat and curve surfaces, by means of simulations of input impedance, reflection coefficient, gain and read range. Measurements of reflection coefficient were also developed. Results prove that the tag antenna can be wrapped on cylindrical surfaces with read ranges above one meter, suitable for applications related to industrial asset management, access control and identification of small objects such as hardware tools, tin cans, spray bottles and tin PET cylindrical containers.

A Novel Finger-Controlled Passive RFID Tag Design for Human-Machine Interaction.

Radio frequency identification (RFID) has shown its potential in human–machine interaction thanks to its inherent function of identification and relevant physical information of signals, but complex data processing and undesirable input accuracy restrict its application and promotion in practical use. This paper proposes a novel finger-controlled passive RFID tag design for human–machine interaction. The tag antenna is based on a dipole antenna with a separated T-match structure, which is able to adjust the state of the tag by the press of a finger. The state of the proposed tag can be recognized directly by the code received by the RFID reader, and no complex data processing is needed. Since the code is hardly affected by surroundings, the proposed tag is suitable to be used as a wireless switch or control button in multiple scenarios. Moreover, arrays of the proposed tag with rational tag arrangements could contribute to a series of manual control devices, such as a wireless keyboard, a remote controller, and a wireless gamepad, without batteries. A 3 × 4 array of the finger-controlled tag is presented to constitute a simple passive RFID keyboard as an example of the applications of the proposed tag array and it refers to the arrangement of a keypad and can achieve precise, convenient, quick, and practical commands and text input into machines by pressing the tags with fingers. Simulations and measurements of the proposed tag and tag array have been carried out to validate their performances in human–machine interaction.

Radio Frequency Identification (RFID) Tag Antenna Design at Ultra High Frequency (UHF) Band

This project is to design a Radio Frequency Identification (RFID) high sensitivity tag antenna which operates at UHF frequency band in Malaysia between 919 MHz to 923 MHz. RFID is a type of wireless and radio wave technology that allows for a small RFID chip to be embedded in certain physical object and uniquely identified by an RFID reader. The major contempilation is that the tag antennas will have longer read ranges but in small sizes. While reducing the size of these antennas cause gain decrease will cause reduction in the read range. Another challenge in designing passive RFID tags antennas is to have the highest impedance matching to achieve high efficiency and low effects of the electromagnetic environment. This project was providing two methods to overcome those problems. Firstly, construct meander line structure to reduce the antenna size and design proposed tag antenna with T-match circuit to achieve conjugate matching with the application-specific integrated circuit so that the reading range of the RFID tag is greatly enhanced. On the other hand, the result show the tag directivity and gain was meets the RFID tag design requirements. This project is useful to be implemented in the RFID industry based on today’s technology.

Design of an HF-Band RFID System with Multiple Readers and Passive Tags for Indoor Mobile Robot Self-Localization.

Radio frequency identification (RFID) technology has already been explored for efficient self-localization of indoor mobile robots. A mobile robot equipped with RFID readers detects passive RFID tags installed on the floor in order to locate itself. The Monte-Carlo localization (MCL) method enables the localization of a mobile robot equipped with an RFID system with reasonable accuracy, sufficient robustness and low computational cost. The arrangements of RFID readers and tags and the size of antennas are important design parameters for realizing accurate and robust self-localization using a low-cost RFID system. The design of a likelihood model of RFID tag detection is also crucial for the accurate self-localization. This paper presents a novel design and arrangement of RFID readers and tags for indoor mobile robot self-localization. First, by considering small-sized and large-sized antennas of an RFID reader, we show how the design of the likelihood model affects the accuracy of self-localization. We also design a novel likelihood model by taking into consideration the characteristics of the communication range of an RFID system with a large antenna. Second, we propose a novel arrangement of RFID tags with eight RFID readers, which results in the RFID system configuration requiring much fewer readers and tags while retaining reasonable accuracy of self-localization. We verify the performances of MCL-based self-localization realized using the high-frequency (HF)-band RFID system with eight RFID readers and a lower density of RFID tags installed on the floor based on MCL in simulated and real environments. The results of simulations and real environment experiments demonstrate that our proposed low-cost HF-band RFID system realizes accurate and robust self-localization of an indoor mobile robot.

Ultralong-Range RFID-Based Wake-Up Radios for Wireless Sensor Networks

This letter presents three different strategies for waking up wireless sensor network (WSN) motes via radio frequency identification (RFID). Based on our prior work on the design of augmented ultrahigh-frequency RFID tags and ultrasensitive RF energy harvesters, the proposed solutions significantly outperform state-of-art RFID wake-up radios (both broadcast based and ID based) for WSNs. In particular, improvements up to 4.2× and 7.8× have been achieved in terms of wake-up range and wake-up delay, respectively.

Optimization of Design Parameters for Radiofrequency Identification Tag Rectifier using Taguchi Methods

This paper outlines the Taguchi optimization methodology, which is applied to optimize the significant parameters in designing the radiofrequency identification (RFID) tag rectifier. The design parameters evaluated are size of transistor (W/L), number of stage (N), and capacitor (C) which realized could gain the circuit performance. An Orthogonal array, signal to noise ratio (S/R), and Pareto analysis of variance are employed to analyze the effect of this design parameter. Through statistical analysis, the optimal variable combination for high-output voltage and low power is 8 μm for W/L, 150 pF for capacitor, and four number of stage. Using the Taguchi method for design of experiment, other significant effects such as the interaction among the design parameters are also investigated. The study shows that the Taguchi is very suitable to solve the stated problem with a minimum number of trials and can be applied in RFID tag design. Other RFID researchers are recommend to consider about this method to be one of design methodology in their work as well.

A Measurement Technique for Verifying the Match Condition of Assembled RFID Tags

In radio frequency identification (RFID) tag design, many measurement methods are available for individually characterizing either the RFID chip or the antenna; however, to the best of the knowledge of the authors, no direct method has been developed for the assembled RFID tag. In this paper, a measurement method for verifying the match condition of the assembled RFID tag is proposed. The proposed method can not only verify the final impedance match condition of the assembled RFID tags but also be used to identify the resistance and reactance mismatch condition between the RFID chip and the antenna. Furthermore, the measurement data obtained from the verification method can be used to estimate the assembly error introduced by different mounting methods. The use of the corrected circuit model of the RFID chip impedance, which includes the assembly error, helps improve the accuracy of the RFID tag design. Five RFID tag antennas, each with a different complex impedance, are used to verify the proposed method. This paper compares the simulated and measured results to illustrate the application of the proposed verification method to the aforementioned RFID tag antennas. It is shown that the experimental tests for the maximum read range agree well with the measured data generated by using the proposed verification method.

Radar Cross-Section Analysis of Backscattering RFID Tags

In this letter, we present a graphical method based on Green's analysis of scattering antennas to optimize the load impedances for achieving maximum modulated radar cross-section (RCS) of backscattering radio-frequency identification (RFID) tags. A planar tag antenna specifically designed for working in the ultra-high-frequency band is used to experimentally validate the method. The measured RCS of the loaded tag antenna shows acceptable agreement with the theory and simulated results. This method is especially valuable to the design of semipassive RFID tags when the communication range is solely determined by the backscattering modulation efficiency of tags.

A small OCA on a 1/spl times/0.5-mm/sup 2/ 2.45-GHz RFID Tag-design and integration based on a CMOS-compatible manufacturing technology

This letter reports, for the first time, on the design strategy and process integration for a small on-chip-antenna (OCA) with a radio-frequency identification (RFID) tag chip-area /spl sim/1/spl times/0.5 mm/sup 2/. It is designed based on a 2.45-GHz RFID tag circuit with an inductive-coupling model. A patterned Al shielding layer is used to improve the consistency of the actual performance obtained from fabricated devices and those predicated from the design. The antenna's inductor coils were fabricated based on a conventional Cu-Damascene process. To achieve the required antenna performance (e.g., Q-factor), a set of thick USG and deep-via etch processes were specifically developed. Our results demonstrate that the dc power converted by the OCA is sufficient to enable the RFID tag chip to communicate with a corresponding 2.45-GHz RFID reader with a 1-mm distance.