• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.108-111
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• 2011

도서관에 RFID 시스템을 도입함으로써 업무의 효율을 높일 수 있다. R-LIM2는 도서의 위치까지 안내하는 기능을 제공하는 RFID 기반의 진보된 도서관리 시스템이지만 위치 추정과 내비게이션에 다수의 안테나 및 별도의 PDA를 사용함으로써 경제적으로는 비효율적이었다. 이에 본 논문에서는 R-LIM2의 내비게이션 기능을 별도의 기기 없이 사용자가 휴대한 스마트폰으로 가능하게 하고, 기존에 구축되어 있는 무선 네트워크 인프라를 활용하여 위치 추정이 가능하게 함으로써 보다 경제적이고 효과적인 도서위치 검색 시스템을 개발하였다.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.353-356
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• 2005

There have been many researches on the antenna performance degradation with the presence of the human body around the antenna structure to accomodate personal communication service [1][2]. To better understand the human body effects on the antenna resonance, radiation pattern, and input impedance, simulation was carried out with changing of the distance between antenna and lossy material. Effects on the antenna performance by the surrounding materials are also important in the case of the RFID system. It is desirable that the tag antennas for RFID system must reveal isotropic radiation pattern as well as attain the good impedance matching. In this paper, we investigated the antenna resonance and input impedance characteristic when there exist a lossy material sphere near various types of antenna at 900 MHz. In short antenna resonance was mostly affected by lossy material in the case of a rectangular loop antenna, and impedance variation was smallest in the case of a halfwave dipole.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.4
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• pp.203-211
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• 2013

UHF RFID tag designers usually ndde the chip impedance and read power sensitivity value obtained when a tag chip is mounted on a chip pad. The chip impedance, however, is not able to be supplied by chip manufacturer, since the chip impedance is varied according to tag designs and fabrication processes. Instead, the chip makers mostly supply the chip impedances measured on the bare dies. This study proposes a chip impedance and read power sensitivity evaluation method which requires a few simple auxiliary and some RF measuring equipment. As it is impractical to measure the chip impedance directly at mounted chip terminals, some form test fixture is employed and the effect of the fixture is modeled and de-embeded to determine the chip impedance and the read power sensitivity. Validity and accuracy of the proposed de-embed method are examined by using commercial RFID tag chips as well as a capacitor and a resistor the value of which are known.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04b
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• pp.55-56
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• 2009

Small RFID tag antenna were fabricated on Si substrate and their physical and electrical properties were evaluated. With decreasing the size of tag antenna on Si substrate, small SMD-type RFID tags could be fabricated, which is very useful for PCB tracking. Firstly, tag antenna pattern and the electromagnetic properties were simulated with HFSS. The frequency was 13.56MHz, the line-width and line-gap were modeled in the range of $50{\sim}200{\mu}m$. S parameters, SRF, and Q value were calculated from geometry. When the line-width and line-gap were 100um and the loop-turn was 10, the SRF was 80MHZ and the Q value was ca. 9. When the microstrip antenna pattern of aluminum was fabricated by using DC sputtering, Vpp of ca. 1.6V was obtained when the reader-tag distance was 40mm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.8A
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• pp.661-668
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• 2012

In this paper, we introduce the low power wireless communication method and propose new protocol and algorithm for wireless communication which can be applied Active RFID system. Transceiver module is composed of MCU, RF transceiver and chip antenna. and it used the lithium coin battery for power supply. The experimental result is confirmed minimum power consumption which show average $10{\mu}A$(packet transmit) and $30{\mu}A$(packet receive) per second. It can be used ultra low power wireless communication. this result is possible for using the algorithm which predict the arrival time of packet. and it indicates that are possible to prevent malfunction and enhance responsiveness.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.2
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• pp.93-98
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• 2018

This paper introduces the development of HF(NFC) and UHF band(13.56 MHz, 920 MHz) tag antennas, imbedded in a box. In dual band antennas, the HF band tag can be used to inspect the box using NFC, and the UHF band tag can be used for logistics. The dielectric constant of the box material is measured and used for simulation. The Ntag213 chip manufactured by NXP is used in HF loop antennas, since NFC is possible with Ntag213. For the UHF band, the Higgs-3 chip manufactured by Alien is used. The HF tag antenna is located at the center of the UHF tag antenna, and the location of the HF tag antenna is calculated while considering coupling effects. The designed tag can be used by both the bands for the purposes of logistics and authentication.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.3
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• pp.195-198
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• 2013

Many libraries utilize RFID tags for checking in and out of books. However, the recognition rate of this automatic process may depend on the orientation of antennas and RFID tags. Therefore we need supplemental systems to improve the recognition rate. The proposed algorithm sets up the ROI of the book existing area from the input image and then performs Canny edge detection algorithm to extract edges of books. Finally Hough line transform algorithm allows to detect the number of books from the extracted edges. To evaluate the performance of the proposed method, we applied our method to 350 book images under various circumstances. We then analyzed the performance of proposed method from results using recognition and mismatch ratio. The experimental result gave us 97.1% accuracy in book counting.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.2
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• pp.140-147
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• 2011

In this paper, we propose a novel feeding method that uses a windshield ground in a vehicle. The feeding method enables for various antennas to integrate easily in a vehicle windshield. To connect a coaxial feeding cable directly to the windshield ground, we inserted a coaxial-to-ground adapter between the cable and the ground, and reflection coefficients using the proposed feeding method were compared to that using a conventional feeding method. The size and position of the windshield ground were optimized in order to achieve a high radiation gain in the azimuth direction. Then the triangular WiBro patch antenna, incorporating the proposed feeding method, was designed and installed on a rear windshield of a commercial sedan. The antenna using the proposed feeding method shows a similar reflection coefficient, and it shows 2 dB increased average azimuth radiation gain compared to that using a conventional sash ground method. These results demonstrate that the proposed feeding method can be applicable for integrating multiple antennas in a rear windshield.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.3
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• pp.747-754
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• 2013

This paper proposed a new transponder detection method to reduce tag recognition time and simplify anti-collision process in RFID systems. In conventional systems, a transponder in detectable area is passively recognized by responding to a reader command. In addition, if there are multiple tags in the area, a collision between tags occurs by responding at the same time to a command and anti-collision process begins. In the proposed method, tags are actively recognized without any command from a reader which results to reducing a tag recognition time and simplifying anti-collision process. To compare transponder recognition time, the process of transponder recognition in conventional systems is analysed. A circuit to detect transponder directly is developed and antenna voltage variation of a reader in the appearance of multiple transponders is analysed for the implementation of the proposed method.

• Journal of the Korea Society of Computer and Information
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• v.15 no.4
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• pp.75-82
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• 2010

At this time, our country's social welfare system for the handicapped is switching to increase independence, education is the most important. This study increases the quality of Visual handicapped people's life which have limit to learn and reduces their inconvenience which may occur during their independent school life through the development of the system which helps them safely to reach their destination by themselves using IT technologies in an educational institute which helps their ability to get information and be independent. This study supports Visual handicapped people to move safely by using cell phone which is necessary items for most modern people, RFID tags and white canes with antenna and reader which read the information installed in the raised blocks outside of school buildings and in the hall or aisle inside of buildings and inform the path by voice and vibration.