Ultra High Frequency Radio Frequency Identification Research Articles

Offset-Fed Folded Dipole and Its Application As RFID Tag Antenna

This paper introduced an offset-fed folded dipole and its application for RFID tag antenna which is capable of working on both metal and non-metal objects with moderate reading range. The antenna itself takes a very simple form and has a single layer structure. As a result, the proposed antenna could serve as a low cost solution for ultra high frequency RFID tags. A transmission line model was proven to be highly accurate for the proposed antenna, which makes the design process simple and effective. The proposed antenna can be designed to have stable input impedance by tuning the location of feed point. Two different types of prototypes were fabricated and tested.

On‐metal UHF‐RFID passive tags based on complementary split‐ring resonators

The use of complementary split-ring resonators (CSRRs) as radiating elements in low-profile on-metal ultra-high-frequency radio-frequency identification (UHF-RFID) tags is explored in this study. First, the radiation properties of the edge-coupled and the non-bianisotropic (NB-CSRR) versions of the CSRR are studied. The tag design strategy is then discussed in detail. On that basis, a compact (λ 0/7 × λ 0/7) low-profile (1.27 mm) tag prototype based on the non-bianisotropic version of the CSRR (NB-CSRR) antenna is designed and manufactured to operate in the North-American UHF-RFID band. The experimental results validate the theoretical and simulated behaviour, and exhibit a maximum read range of 6.8 m.

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.

Design of a Near-Field Nonperiodic Zero Phase Shift-Line Loop Antenna With a Full Dispersion Characterization

The tradeoff between the magnetic field distribution, the magnetic field intensity, and the interrogation zone size is one of the most challenging issues in designing a zero phase shift-line (ZPSL) loop antenna for near-field ultrahigh-frequency radio frequency identification (RFID) applications. In this communication, the dispersion characteristics, including phase and attenuation constants, of the ZPSL in a loop configuration are thoroughly analyzed, such that the important design tradeoff can be fully quantified. Based on the dispersion characteristics, a nonperiodic ZPSL loop antenna with nonuniformly arranged unit cells is proposed. Compared with the periodic configurations, the proposed nonperiodic ZPSL loop antenna shows an improved magnetic field distribution with an enhanced magnetic field intensity.

Wideband high gain circularly polarized UHF RFID reader microstrip antenna and array

This paper presents a wideband and high gain circularly polarized ultra-high- frequency (UHF) radio frequency identification (RFID) reader microstrip antenna and array. Such antenna unit is composed of one main radiation patch and one parasitic radiation patch with air as the dielectric spacer. Two feeding lines connect to the main radiation patch with 90deg phase difference. Numerical optimizations and experimental demonstrations are performed to investigate the performances of the proposed antenna unit and good agreements are obtained. This antenna unit can cover the whole UHF band (860–960MHz) with gain of 9.7dBi. Then two antenna arrays of 1×4 and 2×2 based on previously demonstrated antenna unit are numerically investigated. The array performances, including the gain, beam scanning and low side-lobe are discussed. The obtained results in this paper indicate that the proposed antenna and array are suitable for the universal UHF RFID applications.

Effect of skin dielectric properties on the read range of epidermal ultra-high frequency radio-frequency identification tags.

This Letter presents an investigation of the effect of human tissue conductivity and permittivity on the performance of epidermal transfer tattoo ultra-high frequency radio-frequency identification (RFID) tags. The measurements were carried out on 20 individuals and the variations in the measured dielectric properties correlate well with variations in the measured tag read range on the individuals and to a lesser extent with their body mass index values. Simulation results also showed the effects of permittivity and conductivity on the designed resonance frequency of the RFID tag.

Wheat gluten, a bio-polymer to monitor carbon dioxide in food packaging: Electric and dielectric characterization

The use of wheat gluten as sensing material to detect carbon dioxide is a promising approach. The dielectric properties of wheat gluten are modified in contact with carbon dioxide gas at high relative humidity (90%) and at a temperature of 25°C due to a structural change in the sensing material, where amino groups act as receptors to carbon dioxide molecules. In the present study, the effects of carbon dioxide on the electrical and dielectric properties of wheat gluten at 20% and 90% of relative humidity (usually found in food packaging) are determined and discussed. At 90% of relative humidity, a linear increase of the dielectric permittivity and dielectric loss was observed with a significant hysteresis which increased with the number of carbon dioxide treatment cycles. One of the significant results is the increase in the dielectric permittivity from 7.01±0.07 to 12.02±0.03 with a sensitivity of 31.38±0.06fF/%CO2 measured at 868MHz. The developed sensor is sought to be integrated in the design of UHF-RFID (ultra-high frequency − radio frequency identification) systems working at 868MHz.

Range Estimation and Performance Limits for UHF-RFID Backscatter Channels

The accuracy of time-of-flight-based ranging over ultra-high frequency (UHF) radio frequency identification (RFID) backscatter channels is fundamentally limited by the available bandwidth and highly dependent on the channel characteristics. Comprehensive wideband channel measurements are presented and analyzed with respect to parameters which influence the potential ranging performance. The Cramer Rao lower bound on time-of-flight-based ranging is evaluated and we study the influence of dense multipath on the bound. Based on a line-of-sight (LOS) plus dense multipath (DM) radio channel model, a multiple-input multiple-output (MIMO) ranging algorithm is developed, capable of iteratively estimating the LOS parameters and the statistics of the DM. The accuracy of the developed algorithm is compared to the performance bound. The results highlight the tradeoff between a higher bandwidth and spatial diversity for UHF RFID systems with respect to time-of-flight-based ranging. In a $\boldsymbol {2\times 2}$ MIMO setup, an accuracy of about 0.5m is achieved at a bandwidth of 50 MHz.

Planar Compact Square-Ring Tag Antenna With Circular Polarization for UHF RFID Applications

This paper describes a novel compact design of a planar circularly polarized (CP) tag antenna for use in a ultrahigh frequency (UHF) radio frequency identification (RFID) system. Introducing the meander strip into the right-arm of the square-ring structure enables the measured half-power bandwidth of the proposed CP tag antenna to exceed 100 MHz (860-960 MHz), which includes the entire operating bandwidth of the global UHF RFID system. A 3-dB axial-ratio bandwidth of approximately 36 MHz (902-938 MHz) can be obtained, which is suitable for American (902-928 MHz), European (918-926 MHz), and Taiwanese UHF RFID (922-928 MHz) applications. Since the overall antenna dimensions are only 54 × 54 mm 2 , the proposed tag antenna can be operated with a size that is 64% smaller than that of the tag antennas attached on the safety glass. With a bidirectional reading pattern, the measured reading distance is about 8.3 m. Favorable tag sensitivity is obtained across the desired frequency band.

An Energy-Efficient ECC Processor of UHF RFID Tag for Banknote Anti-Counterfeiting

In this paper, we present the design and analysis of an energy-efficient 163-b elliptic curve cryptographic (ECC) processor suitable for passive ultrahigh frequency (UHF) radio frequency identification (RFID) tags that are usable for banknote authentication and anti-counterfeiting. Even partial public key cryptographic functionality has long been thought to consume too much power and to be too slow to be usable in passive UHF RFID systems. Utilizing a low-power design strategy with optimized register file management and an architecture based on the Lopez-Dahab Algorithm, we designed a low-power ECC processor that is used with a modified ECC-DH authentication protocol. The ECC-DH authentication protocol is compatible with the ISO/IEC 18000-63 (“Gen2”) passive UHF RFID protocol. The ECC processor requires 12 145 gate equivalents. The ECC processor consumes 5.04 nJ/b at a frequency of 960 kHz when implemented in a 0.13- $\mu \text{m}$ standard CMOS process. The tag identity authentication function requires 30 600 cycles to complete all scalar multiplication operations. This size, speed, and power of the ECC processor makes it practical to use within a passive UHF RFID tag and achieve up to 1500 banknote authentications per minute, which is sufficient for use in the fastest banknote counting machines.

Possibilities of Fabricating Copper-based RFID Tags with Photonic-sintered Inkjet Printing and Thermal Transfer Printing

This letter studies the possibilities of manufacturing copper-based passive ultrahigh frequency (UHF) radio frequency identification (RFID) tags using inkjet and thermal printing on two substrate materials, polyimide (Kapton), and a polyester-based substrate (Flexcon THERMLfilm). Both printing methods are tested to fabricate different tag designs, and the performance of successfully printed tags is evaluated using wireless measurements. Measurement results show that both printing methods, while using copper material, can be used to effectively fabricate passive UHF RFID tag antennas on selected substrates.

A Novel Broadband Antenna Design for UHF RFID Tags on Metallic Surface Environments

In this letter, a novel ultrahigh-frequency radio frequency identification (UHF RFID) tag antenna is proposed. Suitable for metallic objects, this broadband antenna can cover the three major UHF RFID bands. A modified folded dipole and a meander bar have been implemented on the upper substrate, while the second substrate is a double face with parallel bars printed on the top face and a metal plane on the bottom to isolate the antenna from metallic surfaces. The bars are used as parasitic elements to excite multiresonant modes and enhance the antenna bandwidth. To improve the gain of the antenna, the two substrates have been speared by an air layer. Furthermore, the proposed design is cost-effective since it does not require metallic vias. Mounted on a metallic plate of 300 × 250 mm2, the proposed antenna covers the targeted UHF RFID bands with a return loss better than 10 dB and a maximum outdoor measured reading range of 14.6 m at 905 MHz.

3D Printed and Photonically Cured Graphene UHF RFID Tags on Textile, Wood, and Cardboard Substrates

This paper introduces 3D direct writing and microdispensing of graphene ultrahigh frequency (UHF) radio-frequency-identification (RFID) antennas on textile, wood, and cardboard substrates, subsequently cured either by conventional oven or photonically by pulsed Xenon flashes. Photonic-cured passive UHF RFID graphene tags on cardboard, wood, and textile substrates achieve read ranges of 5.4, 4.6, and 4 meters, respectively. These results are superior to those achieved by the oven-cured tags that featured read ranges of 4.8, 4.5, and 3.6 meters, respectively. This work presents the first integration of 3D printing and photonic curing of graphene antennas on low-cost versatile substrates.

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 Yagi–Uda Antenna With Load and Additional Reflector for Near-Field UHF RFID

In this letter, a Yagi–Uda antenna with load and additional reflector is proposed to achieve strong and uniform magnetic field distribution within the antenna area for near-field ultrahigh-frequency radio frequency identification (RFID). This proposed antenna is composed of one driven dipole to emit electromagnetic (EM) wave, several directors to direct the EM wave to the desired area, a load element at the end of the director array to absorb the wave, and two reflectors at both ends to reflect the EM wave. The proposed antenna can generate a uniform magnetic field distribution within the antenna area, meanwhile keeping the field strength outside the antenna area relatively small. A prototype, as an example, that contains 13 elements is designed and fabricated, with the measured bandwidth of 880–980 MHz. The achieved interrogation area is 440 × 160 mm2, measured by utilizing a commercial RFID reader and some near-field tags. It is worth mentioning that the interrogation area can be extended by adding more directors to the antenna.

A Miniaturized Metamaterial Absorber for Ultrahigh-Frequency RFID System

An ultrahigh-frequency (UHF) miniaturized metamaterial absorber (MMA) using incurved square loop loaded with lumped resistors is proposed in this letter. The size of the unit cell is miniaturized to be only 20 × 20 mm2 , about 0.0036 ${{\rm{\lambda }}^{\rm{2}}}$ at the center frequency (910 MHz), which is only a quarter of the size of a conventional UHF metamaterial absorber unit cell. Detailed simulations and experimental results show that the MMA covers the worldwide UHF radio frequency identification (RFID) operation band (860–960 MHz) with absorptivity more than 90% over a certain range of incident angles. Thus, the MMA can be used to improve performance of RFID systems, especially suitable for the use in restricted spaces.

A Novel 3-D Tag With Improved Read Range for UHF RFID Localization Applications

In this letter, a novel compact 3-D passive radio frequency identification (RFID) tag is proposed for indoor localization applications operating at the ultrahigh-frequency RFID European band (865–868 MHz). By perpendicularly embedding a reflector plane in its middle, the tag read range has been expanded with minimum leverage through the environment perturbations. The proposed cost-effective 3-D tag exhibits a read range of 30.5 m with a transmitting output power of 33.4 dBm as well as a measured gain of 3.55 dBi, and 86.13% efficiency at 866.5 MHz. Successfully tested under real operating conditions (in building hallway), the proposed tag demonstrated its suitability for indoor localization and/or navigation applications.

Embroidered Antenna-Microchip Interconnections and Contour Antennas in Passive UHF RFID Textile Tags

We studied the possibilities of embroidered antenna-IC interconnections and contour antennas in passive ultrahigh-frequency radio-frequency identification textile tags. The tag antennas were patterned from metal-coated fabrics and embroidered with conductive yarn. The wireless performance of the tags with embroidered antenna-IC interconnections was evaluated through measurements, and the results were compared to identical tags, where the ICs were attached using regular conductive epoxy. Our results show that the textile tags with embroidered antenna-IC interconnections attained similar performance. In addition, the tags where only the borderlines of the antennas were embroidered showed excellent wireless performance.

Design of a UHF wide‐band antenna with a compact notch filter

A novel ultra high frequency (UHF) broadband polygonal monopole antenna with a notch is presented. The antenna is a wineglass-shaped geometry near two pairs of long-horn-shaped coupling elements located on the top and bottom surfaces to cover the band of 700 MHz–1.3 GHz with the size of 150 × 100 × 1.2 mm. The notch filtering is achieved at 900 MHz by using the open-terminated stub of a novel composite right/left handed transmission-line phase shifter. The phase shifter is 12 mm as 0.07 × λg. The validity of the proposed scheme is verified by designing and comparing the wide-band antenna with different notch-making approaches through electromagnetic simulation, fabrication and measurement. The simulated and measured results show high degrees of agreement. The suggested antenna is shown to be useful for UHF-band applications with a stopband at 900 MHz to avoid potential interference from the GSM-E service, Z-wave communication and UHF radio-frequency identification tag frequencies.

Wireless, Room Temperature Volatile Organic Compound Sensor Based on Polypyrrole Nanoparticle Immobilized Ultrahigh Frequency Radio Frequency Identification Tag.

Due to rapid advances in technology which have contributed to the development of portable equipment, highly sensitive and selective sensor technology is in demand. In particular, many approaches to the modification of wireless sensor systems have been studied. Wireless systems have many advantages, including unobtrusive installation, high nodal densities, low cost, and potential commercial applications. In this study, we fabricated radio frequency identification (RFID)-based wireless sensor systems using carboxyl group functionalized polypyrrole (C-PPy) nanoparticles (NPs). The C-PPy NPs were synthesized via chemical oxidation copolymerization, and then their electrical and chemical properties were characterized by a variety of methods. The sensor system was composed of an RFID reader antenna and a sensor tag made from a commercially available ultrahigh frequency RFID tag coated with C-PPy NPs. The C-PPy NPs were covalently bonded to the tag to form a passive sensor. This type of sensor can be produced at a very low cost and exhibits ultrahigh sensitivity to ammonia, detecting concentrations as low as 0.1 ppm. These sensors operated wirelessly and maintained their sensing performance as they were deformed by bending and twisting. Due to their flexibility, these sensors may be used in wearable technologies for sensing gases.