• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.1
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• pp.15-21
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• 2016

In this paper, we considered a design method of a compact quasi-Yagi antenna for portable UHF RFID readers. The antenna consists of a dipole driver and a reflector printed on a dielectric substrate, and it is fed by a microstrip line. In order to reduce the antenna size, the dipole and reflector are bent and the balun between the feeding microstrip line and coplanar strip (CPS) line is integrated within the CPS line. The effects of the geometrical parameters of the proposed antenna on the antenna performance are examined, and the parameters are adjusted to be suitable for the operation in UHF RFID band (902-928 MHz). The size of the fabricated antenna is $70mm{\times}75mm$, and the experiment results reveal a frequency band of 892-942 MHz for a voltage standing wave ratio < 2, a gain > 3.5 dBi, and a front-to-back ratio > 6.6 dB over the frequency band for UHF RFID.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.1
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• pp.193-198
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• 2009

In this paper, we report the design of UHF RFID ceramic antenna using HFSS, one of the widely used RFID design tools. Of the developed antenna system, we analyze its Return Loss using HFSS and its characteristics using Smith Chart methodology. We built the ceramic antenna system based on the HFSS design, and analyzed its performance by measuring the impedence matching and gains using Network Analyzer. We attach the developed prototype to UHF RFID portable terminal, and performed distance measuring for five widely used types of RFID tags to verify the performance of our proposed antenna system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.1
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• pp.131-134
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• 2012

A bar-code shape UHF RFID tag antenna is designed and fabricated with silver conductive ink. It can be recognize by both bar-code scanner and RFID reader. The bar-code shape is taken from a general box of a product, and the product code of the bar-code is used for the antenna design. The tag antenna is fabricated with silver conductive ink using a T-matching structure. The designed tag antenna is satisfied with bar-code system and RFID system simultaneously. The input reflection coefficient characteristics and the reading range pattern are measured. The peak reading range is about 111 cm, which is long enough.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.63-64
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• 2017

In this paper, we studied a design method for a coplanar waveguide-fed compact quasi-Yagi antenna for a dual band of the UHF RFID (915 MHz) and GPS (1.575 GHz). The proposed antenna is composed of three elements of a dipole, a reflector, and a director. To reduce its size, the ends of both the dipole and reflector are bent, the director is placed near to the dipole, and a balun is incorporated in the antenna. From some simulations, the proposed antenna using an FR4 substrate with 0.8 mm thickness was designed for the operations in the UHF RFID and GPS systems, and the antenna characteristics such as reflection coefficient, gain, and radiation patterns were examined.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.5
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• pp.562-571
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• 2008

In this paper, we propose a novel structure of a spiral antenna with a CP characteristic for RFID reader in UHF band. Since the proposed antenna can be built by printing on a FR-4 substrate, it is appropriate for low-cost mass-production. The antenna is designed to operate in UHF band of $860{\sim}960$ MHz. The CP bandwidth is Increased enough to cover an overall UHF RFID band by using a spiral structure for the antenna arm. The matching bandwidth is broadened by using a quarter-wave transformer between the fred and the antenna body. The proposed antenna has advantages of its easy gain and pattern control with a small antenna size. The measured antenna performance shows the matching bandwidth of 13%, the CP bandwidth of 23%, and the gain of 6.5 dBi. This verifies that the proposed antenna is appropriate for RFID antennas in UHF band.

• 한국ITS학회:학술대회논문집
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• v.2006 no.10
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• pp.179-181
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• 2006

톨게이트에서 사용되는 UHF RFID 비발디 배열 안테나를 설계하였다. 안테나의 주파수 대역은 미국 기준의 RFID UHF 대역으로 $902{\sim}928MHz$이다. 안테나 설계는 먼저 단일소자 비발디 안테나를 설계한 후, 전력분배 비율 0.3:1:1:0.3으로 $1{\times}4$ 배열한 안테나로 설계하였다. 설계된 배열 안테나는 VSWR 2:1이하에서 $850{\sim}942MHz$인 S11 특성을 보였다. 이득은 최대방사 9.93dBi를 얻었다. 안테나 제작은 주파수를 높여 scale down하여, 1소자 비발디를 제작하고 이의 특성을 측정하였다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.5
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• pp.46-51
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• 2013

In this paper, a dual-band antenna is proposed for the RF power harvester system as well as RFID tag. The proposed antenna operates as the passive and active RFID tag antenna in the UHF and microwave band, respectively. In addition, to charge the battery of an active RFID tag in the microwave band, it harvest the RF signal for tagging from the passive RFID tag antenna in the UHF band. The proposed antenna operates in the UHF band (917~923.5 MHz) and microwave band (2.4~2.45 GHz). In order to obtain the dual-band operation, the dipole structure and meander parasitic elements are proposed as the ${\lambda}/2$ and $1{\lambda}$ dipole antenna, respectively. The radiating dipole structure in the microwave band acts as the coupled feed for the meander parasitic elements in the UHF band. The impedance bandwidth (VSWR < 2) of the proposed antenna covers 917~923.5 MHz (UHF band) and 2.4~2.45 GHz (Microwave band). Measured total efficiencies are over 45 % in the UHF band and over 70 % in the microwave band. Peak gains are over 0.18 dBi and 2.8 dBi in the UHF and microwave band with an omni-directional radiation pattern, respectively.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.3
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• pp.101-110
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• 2007

This study has designed a circular polarization antenna for UHF bandwidth RFID reader. As a result of performance test of the antenna designed it is found that return loss (S11) is about -45.529dB at 914MHz, which is relatively small, and antenna gain is about 6.09dBi. It has also been confirmed that $50{\Omega}$ impedance matching is about $50.48{$\Omega}$ and it can be applied to every RFID reader. Therefore, the antenna is designed to have higher gain of circular polarization by improving reception, which is one of the most important parameters of RFID reader and is expected to be extensively used to recognize multi-tag in the distance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.11
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• pp.972-977
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• 2016

This paper introduces development process and results of HF & UHF band(13.56 MHz, 920 MHz) tag antennas using a single-side printing method on a PE film. The size of tag antenna is designed in the area of $80mm{\times}50mm$, little bit smaller than a credit card. The UHF tag antenna, $76mm{\times}44mm$, is located at the outside of the card size tag antenna, and the HF tag antenna, $40 mm{\times}42 mm$, is located at the center of the UHF tag antenna. The UHF and HF tag antennas are designed with consideration of coupling effects. The single-side printing method with a jumper structure without using a via is used to make a loop antenna of HF tag antenna. The reading range of UHF tag antenna is about 6m, and the reading of HF tag antenna is about 5 cm. The designed tag antennas have long enough reading ranges for both bands. The tag is applicable to logistics and authentification.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.282-287
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• 2007

A circular UHF RFID tag has been designed. This circular tag antenna can be optimized simply by controling two parameters, outer radius and inner radius of the tag antenna. The resistance and resistance values of the tag antenna have been researched based on the variation of inner and outer radii of the circular tag antenna. The simulation and measurement results are compared.