• The Journal of the Korea Contents Association
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• v.9 no.10
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• pp.67-74
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• 2009

Incorrect deployment of RFID readers occurs reader-to-reader interferences in many applications using RFID technologies. Reader-to-reader interference occurs when a reader transmits a signal that interferes with the operation of another reader, thus preventing the second reader from communicating with tags in its interrogation zone. Interference detected by one reader and caused by another reader is referred to as a reader collision. In RFID systems, the reader collision problem is considered to be the bottleneck for the system throughput and reading efficiency. In this paper, we propose a novel RFID reader anti-collision algorithm based on evolutionary algorithm(EA). First, we analyze characteristics of RFID antennas and build database. Also, we propose EA encoding algorithm, fitness algorithm and genetic operators to deploy antennas efficiently. To show superiority of our proposed algorithm, we simulated our proposed algorithm. In the result, our proposed algorithm obtains 95.45% coverage rate and 10.29% interference rate after about 100 generations.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.8
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• pp.872-879
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• 2010

This paper describes the design for radiation pattern directivity of vehicle license plate RFID tag antenna to improve the readable range. Directivity pattern of the proposed passive antenna is decided by the meander line position and the bumper size attached to the tag antenna. In order to prove the verification of the calculated directivity pattern and readable range of the proposed antenna, the tag antenna has been fabricated and measured at the anechoic chamber. It is shown that the maximum directivity gain of the measured radiation pattern of active and passive tag antenna were observed 2.32 dBi and 3.1 dBi, respectively. The maximum readable range of passive tag antenna was measured about 8.5 m at ${\pm}45^{\circ}$ beam direction on the basis of the driving car direction($0^{\circ}$ of azimuth angle).

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.699-699
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• 2006

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.5
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• pp.480-492
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• 2009

In this paper, we proposed a broadband U-shaped RFID tag antenna with near-isotropic characteristic at UHF band. The proposed tag antenna is composed of the U-shaped half wavelength dipole and a rectangular shaped feed. The rectangular shaped feed that is located inside U-shaped dipole is connected for conjugate impedance matching with the commercial tag chip. A better constant gain deviation characteristic in the operating frequency band is achieved by inserting a rectangular slit in the lower center of the U-shaped antenna body. On the condition of VSWR<2, the tag antenna had the measured bandwidth of 10.36%, from 860.5 to 954.5 MHz, and 9.84%, from 864.5 to 954 MHz, for antenna without slit and with slit, respectively. On the condition of VSWR<5.8, the tag antennas had the measured bandwidth of 15.78%, from 835.5 to 979.5 MHz, and 15.89%, from 837 to 981.5 MHz, for antenna without slit and with slit, respectively. The difference between the maximum and minimum gain deviations of tag antenna without slit in the operating frequency band is 0.53 dB since the maximum and minimum gain deviations are 3.86 dB and 3.33 dB, respectively. Whereas the difference between the maximum and minimum gain deviations of tag antenna with slit in the operating frequency is 0.06 dB since the maximum and minimum gain deviations are 3.60 dB and 3.54 dB, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.8
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• pp.694-700
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• 2009

In this paper, we propose a RFID tag antenna with low performance degradation due to nearby dielectric materials. The proposed antenna is designed to be appropriate for ink printing fabrication. The antenna is designed to operate in UHF band of $860{\sim}960$ MHz. The antenna uses a T-matching network in the middle of the main body and two parasitic patches in vicinity for complex conjugate matching with a commercial tag chip. In addition, the two parasitic patches induce currents at different dielectric constants of nearby dielectric materials. This can minimize the performance degradation due to nearby dielectric materials. The measured results show the half power matching bandwidth from 844 MHT to 1,268 MHz. It exhibits the reading distance of about 3.5 m in free space when the tag antenna is used with the commercial reader antenna (transmitting power of 20 dBm and the reader antenna gain of 6 dBi). When the tag is attached on dielectric materials of wood and FR4, the resulting reading distances are 2.61 m and 2.51 m, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.1 s.92
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• pp.40-48
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• 2005

In this paper, we explore the inductively coupled concept and propose a class of electrically small planar antennas. The antennas are optimized using NEC in conjunction with a Pareto GA. These antennas show good efficiency and bandwidth performance without any additional matching network. Several optimized designs are fabricated and measured. We explain the operating principle of these antennas using a simple lumped element circuit model. The proposed antennas are translated as printed lines on Duroid for RFID tag antennas.

• Journal of Broadcast Engineering
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• v.23 no.6
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• pp.925-930
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• 2018

In this paper, we present a low profile dual-microstripline-fed double 4-arrayed meander monopole antenna with a cross-type element back by separated four-segments mesh-type reflector. The cross-type element and separated four-segments mesh-type reflector leads to enhance radiation patterns and antenna gain characteristics. The measurement value of the proposed antenna show that it has dipole-like radiation pattern characteristics. The experimental peak gain of fabricated antenna is about 2.89 dBi, which presents relatively high gain characteristics for a low profile(small-size) one. This antenna can be applied mobile RFID(radio frequency identification) readers, small medical instruments, broadcasting and home-networking operations, and other low profile high-gain systems.

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.99-102
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• 2009

본 논문에서는 RFID를 이용하여 PC 보안 소프트웨어를 설계 및 구현을 하였다. 본 논문에서 연구한 PC 보안 소프트웨어는 송신기인 RFID Tag와 수신기인 RFID Reader에 연결된 안테나를 통해 서로 통신하여 PC에 설치된 S/W를 이용하여 사용자 인증을 받는 PC 보안 방법이다. 이는 위조 및 변조가 불가능하며, 스니핑 공격 및 스푸핑 공격에 대하여 기존의 PC 보안 시스템보다 안전성이 향상되었다.

• Proceedings of the KAIS Fall Conference
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• 2010.05a
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• pp.572-575
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• 2010

본 논문에서는 RFID를 이용하여 PC 보안 소프트웨어를 설계 및 구현을 하였다. 본 논문에서 연구한 PC 보안 소프트웨어는 송신기인 RFID Tag와 수신기인 RFID Reader에 연결된 안테나를 통해 서로 통신하여 PC에 설치된 S/W를 이용하여 사용자 인증을 받는 PC 보안 방법이다. 이는 위조 및 변조가 불가능하며, 스니핑 공격 및 스푸핑 공격에 대하여 기존의 PC 보안 시스템보다 안전성이 향상되었다.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.4
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• pp.537-542
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• 2014

Track circuit is a simple electrical device which lies in the connection of the two rails by the wheels and axle of locomotives and rolling stock to short out an electrical circuit, used to detect the absence of a train on rail tracks. In railway signaling system, there are similar systems such as RFID and wheel sensor, GPS etc, are research and developing. Hybrid track circuit is using RFID antenna and reader on the cab and RFID tag on the sleeper. because of the safety in railway operation, tag detection of train position detection function in the hybrid track circuit needs high reliability. This paper studied tag recognition enhancement used tag angles.