Ultra High Frequency Radio Frequency Identification Band Research Articles

A circular patch antenna with parasitic element for UHF RFID applications

This article initially proposes a directly-fed circular patch antenna with L-shaped ground plane for Radio Frequency Identification (RFID) applications in the 900 MHz (902−928 MHz) ultrahigh frequency (UHF) band. To achieve circularly polarized (CP) radiation, two arc-shaped notches are loaded into the main patch. To enhance the CP bandwidth so that the proposed antenna can also cover the UHF RFID band for Europe (866−869 MHz), a parasitic element is printed besides the main patch. Experimental measurements show that the 10-dB return loss bandwidth of the proposed antenna was 30.95% (833−1138 MHz) and its corresponding 3-dB axial ratio bandwidth was 8.95% (865−946 MHz). Good gain and radiation efficiency of more than 7 dBic and 90%, respectively, were also exhibited across the two desired UHF RFID bands. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:681–687, 2015.

DESIGN OF MINIATURIZED QUASI-YAGI ANTENNA FOR PORTABLE RFID READER APPLICATIONS

A method to design a miniaturized two-element quasi-Yagi antenna (QYA) with size and gain requirements is presented for portable ultra high frequency (UHF) radio frequency identification (RFID) reader applications. The antenna consists of a driver dipole and a ground reflector, and these elements are serially connected with a coplanar strip line. The ends of both elements are folded back toward each other to reduce the lateral size of the antenna. A detailed design procedure of the proposed antenna is explained, along with a performance comparison for the input impedance, voltage standing wave ratio (VSWR), broadside gain, front-to-back (F/B) ratio, and total efficiency. A prototype antenna, covering the 860-960 MHz UHF RFID band with a gain > 4 dBi, is fabricated on an FR4 substrate with dimensions limited to 90 mm by 90 mm. The total width of the proposed antenna is reduced by approximately 41% compared to the conventional QYA without miniaturization, and an F/B ratio is improved by 1-8 dB in the band. Experiment results show that the proposed antenna has the desired impedance characteristics with a frequency band of 853-1,098 MHz for a VSWR 13 dB is obtained.

Development of an UHF RFID Chemical Sensor Array for Battery-Less Ambient Sensing

Battery-less ultrahigh frequency (UHF) radio frequency identification (RFID) tags coated by proper sensitive layers have been recently demonstrated capable to play as low-cost sensors of some volatile compounds. The issue of cross-sensitivity and the possibility to develop an array of differently coated sensors are, however, still completely open. This paper investigates, through an experimental campaign involving a general-purpose sensor-antenna transducer, the potentiality of functionalized tags in the UHF RFID band to sense a multiplicity of volatile compounds, as well as the cross-sensitivity effects of different coatings in array configuration. Four effective materials, such as Pedot:PSS, doped PSS, SWCNT, and PDAC, revealed a remarkable sensitivity to ammonia, ethanol, octane, and water. Wireless sensing may be hence performed by narrowband processing of the power response of the RFID tags as well as by the broadband extraction of features related to the resonance shift. It was finally observed how the inter-antenna coupling may affect the sensor capability of an array of UHF tags in term of increased cross-sensitivity.

Broadband UHF RFID tag antenna design matched with different RFID chips

ABSTRACTA novel antenna structure with two crab‐shaped patches and a small microstrip dipole is proposed for ultra frequency radio frequency identification (RFID) tag design, which can be directly integrated in metallic plates or other objects. The feature of the design is that the tag antenna can operate effectively with different ultrahigh frequency (UHF) RFID chips, and the design of the conjugate impedance match of the RFID tag can be easily obtained. The important advantages of the antenna structure are that the tag does not have to be redesigned to work with different RFID chips. The antenna's size is 45 mm × 75 mm × 0.5 mm. The antenna achieves 200 MHz bandwidths, which covers worldwide UHF RFID bands (840–960 MHz). Furthermore, the proposed antenna obtains high gains and a good radiation pattern. The simulated and measured results are shown to be in good agreement with each other. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:55–57, 2014

Printed RFID reader antenna with circular polarization for handheld operation

A novel circularly polarized antenna for ultrahigh frequency (UHF) radiofrequency identification (RFID) readers is proposed in this article. A prototype that operates in the UHF RFID band is successfully developed using an orthogonally truncated radiation patch, an obliquely slotted ground plane, and a 50-Ω microstrip line that proximally fed the antenna. All elements are printed on a microwave substrate in a vertical structure. The antenna dimension of 65 × 900 × 8 mm3 is suitable to use for handheld devices. The impedance bandwidth for 2.5 VSWR and the 3-dB axial-ratio bandwidth is 15.2% (880 MHz∼1025 MHz) and 6.5% (890 MHz∼950 MHz), respectively. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2792–2797, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27180

Broadband UHF RFID tag antenna with a rectangular‐loop feed and additional patches

AbstractA novel tag antenna with a rectangular‐loop feed, a bent meandered strip and additional patches is designed and analyzed in ultra high frequency (UHF) radio frequency identification (RFID) bands to provide broadband, high gain, and size‐reduction performance simultaneously. It is designed to operate at UHF RFID bandwidths, with resonant frequencies of 842, 868, and 915 MHz, respectively. The dimension of the antenna with resonant frequencies of 915 MHz is around 78 × 23 mm2, which shows near linear phase characteristics. Simulated and measured results show the proposed antenna can obtain 100 MHz bandwidth under the condition of voltage standing wave ration less than 2 and 1.6 dBi gain for worldwide UHF RFID bands. In addition, the antenna provides a good radiation pattern. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1234–1236, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26804

Inkjet-Printed UHF RFID Tags on Renewable Materials

Radio frequency identification (RFID) provides great potential for different Internet of Things (IOT) applications. In the future, material choices in these IOT devices will have a huge effect on the environment and thus use of renewable materials is a growing trend. In this paper, passive ultra high frequency (UHF) RFID tags were inkjet-printed directly on wood, paper, and cardboard substrates, and their performance was evaluated by measuring two key properties: threshold power and theoretical read range. According to our measurements, the tags on wood showed read ranges of 7 - 8 meters, the tags on cardboard exhibited read ranges of 4 - 7 meters, and the tags printed on paper showed read ranges of 2 - 7 meters through the global UHF RFID band. According to these results, the performance of these inkjet-printed UHF RFID tags is sufficient for many IOT devices and potential applications e.g. in construction and packaging industry.

Study of broadband near-field antenna for ultra-high-frequency radio frequency identification applications

A novel antenna for applications in an ultra-high-frequency (UHF) radio frequency identification (RFID) reader system is proposed and investigated. The antenna achieves a gain of lower than −10 dBi in all directions with strong magnetic field distribution over the entire UHF RFID band of 830–950 MHz as well as good performance in detecting tags when applied in UHF RFID systems. The antenna configuration is described and the principle of operation is explained. To investigate the effects of each parameter on the antenna performance, a comprehensive parametric study is carried out and the results are presented in detail and discussed. To prove the concept, a prototype is developed and fabricated. The measurement results demonstrate that the antenna can achieve a broad bandwidth and low gain, and produce a strong magnetic field with relatively concentrated field distribution in the near-field region of the antenna. Hence, this work is very promising for UHF near-field RFID reader applications.

UHF RFID Reader Antenna for Near-Field and Far-Field Operations

In this letter, a radio frequency identification (RFID) reader antenna designed for near-field and far-field operation at the European ultrahigh frequency (UHF) band is presented. Segmented loop technique is implemented for near-field operation, whereas a patch antenna is included inside the loop for far-field operation. The fabricated antenna works from 864 to 873 MHz with reflection coefficient less than 10 dB, thus covering the European UHF RFID band. Its linearly polarized radiation pattern provides a 4-dBi gain. The reading capabilities of the antenna are up to 9 cm and 6 m for near-field and far-field applications, respectively.

A Broadband UHF Near-Field RFID Antenna

A broadband segmented loop antenna is presented for ultra high frequency (UHF) near-field radio frequency identification (RFID) applications. Using a segmented line, the current distribution along the loop is kept in phase even though the perimeter of the loop is more than two operating wavelengths so that the proposed antenna generates strong and even magnetic field distribution in the near-field zone of the antenna. The antenna prototype, printed onto a piece of FR4 substrate, with an overall size of , achieves a large interrogation zone of with good impedance matching and uniform magnetic field distribution over the entire UHF RFID band of 840-960 MHz.

Performance comparison of folded microstrip patch-type tag antenna in the UHF RFID bands within 865 928 MHz using EPC Gen 1 and Gen 2 standards

Emerging use of passive Ultra-High Frequency (UHF) Radio Frequency Identification (RFID) systems requires application-specific tag antennas for challenging materials. The operability of folded microstrip patch-type tag antenna affixed to objects containing conductive and liquid-based materials is analysed and tested in the UHF RFID bands within 865928 MHz. The performance of the antenna design using Electronic Product Code (EPC) Gen 1 and Gen 2 standards is also analysed. The results show that the antenna design is operable in the studied UHF RFID bands and its performance improves when Gen 2 standard is used.