• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.1 s.343
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• pp.1-8
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• 2006

In this paper, we suggested a new antenna structure for the RFID(Radio Frequency IDentification) reader. The conventional RFID reader uses a loop antenna. The central area of a loop antenna shows a low magnetic field strength, especially for the case of a large loop antenna diameter. We proposed a parallel-fed multiple loop antenna. Simulation and measurement were carried out for a single loop antenna, series-fed and parallel-fed multiple loop antennas. Simulation results show that we can obtain 0.40A/m, 0.68A/m, 1.98A/m of magnetic field strengths at the central point of a reader antenna for a single loop antenna, series-fed and parallel-fed multiple loop antennas, respectively. We measured the $79mm{\time}48mm$ tag area averaged induced voltages with applying 20Vp-p same source signals to reader antennas through the resistors. Measured tag area averaged induced voltages at the central point of a reader antennas were 0.76V, 1.45V, 4.04V for a single loop antenna series-fed and parallel-fed multiple loop antennas, respectively. The results show that we can get high induced voltage which can grantee a longer reading distance with a proposed parallel-fed multiple loop antenna.

• Journal of Korea Multimedia Society
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• v.12 no.9
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• pp.1288-1296
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• 2009

This paper is for multi-frequency thin film loop antenna used on smart phone, PMP and PDA like as a multi-media devices. We developed a loop pattern folding methods to reduce a thin film antenna dimension using that mutual coupling folding loop occurs the higher frequency resonation. To reduce the thin film size for loop antenna, we fold the loop pattern repeatedly control the coupling coefficient than generate a not only higher mode resonation but also basic resonation from loop pattern. To realization the thin film folded loop antenna, we used a $30mm{\times}9mm$ PI film the thickness is 20um so that we realize the CDMA850, GPS, DCS, PCS, WCDMA antenna simultaneously and it's radiation efficiency is over 50% and gain is 0dBi.

• Journal of Korea Multimedia Society
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• v.12 no.7
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• pp.971-978
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• 2009

The paper is a phase controlled loop antenna for multi-media devices. We developed a phase control loop pattern arrangement methods for loop antenna in mobile devices like as a cell phone and PCS, WCDMA. In the loop antenna pattern, arrange close adhesive the loop antenna pattern $180^\circ$ cycle in wave length, the radiated electro-magnetic wave from close adhesive loop pattern become to coherent wave than the phase controlled loop antenna has high efficiency and high radiation gain. To acquire a wide band width on phase controlled loop antenna, we arrange a multiple phase controlled loop pattern that has a different length each other. Different length for each other loop pattern cause a different frequency that we can acquire a wide band width for loop antenna from close adhesive phase control. In experiment, we designed a CDMA850 mobile multi-media antenna in 20mm$\times$20mm area thickness 0.4mm, the radiation efficiency is over 60% and radiation gain is over 0dBi.

• Proceedings of the KAIS Fall Conference
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• 2002.05a
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• pp.209-211
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• 2002

차량 탑재 FM 수신용 전 방향성 루프 안테나를 개발하였다. 2개의 수직 루프를 90도 교차하고, 1개의 수평 루프와 결합함으로써 전 방향 특성을 가질 수 있다. 또한 수직 및 수평편파 모두를 박기 때문에 도심 등 주위 환경변화에 따른 편파 다이버시티 현상도 제거한 수 있다. 10cm 직경의 19회 감긴 각 루프를 정합시키고 증폭하여, 90도 이상기와 함께 결합한 안테나를 개발하였다. FM 대역인 88-108MHz 대역에서 측정된 반사특성 및 패턴은 이론치와 잘 맞고 있으며, 기존 whip안테나 보다 평균 4dB 향상된 수신전력 특성을 보이고 있다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.10
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• pp.1845-1851
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• 2016

In this paper, a design method for a wideband square loop antenna for Digital TV applications is studied. The proposed loop antenna is a square loop antenna combined with circular sectors to connect with central feed points. The square loop is used instead of the circular loop in order to miniaturize the antenna size. The input reflection coefficient and gain characteristics of the proposed antenna are analyzed to match with the 75 ohm port impedance for DTV applications. The effects of the gap between the circular sectors and the length of the square loop on the input reflection coefficient and gain characteristics are examined to obtain the optimal design parameters. The optimized antenna is fabricated on an FR4 substrate, and the experiment results show that it operates in the frequency band of 470-1,300 MHz for a VSWR < 2, which assures the operation in the DTV band.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.11A
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• pp.912-920
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• 2003

This paper is about the design of a small wide-band slot loop antenna, which consists of dual offset-fed and rectangular loop within the slot on a substrate. The proposed antenna is a novel structure generating a multi-resonances due to three geometrical resonance structures. The impedance matching of this antenna can be accomplished by changing the offset position of dual-fed at resonance frequencies. In this experiment, the slot of a fabricated antenna has a center frequency of 6.755㎓, 12.5mm${\times}$50mm in size and the rectangular loop has 10.5mm${\times}$27.5mm in size. The measured result is fractional bandwidth 63.21% with VSWR 2:1, which is agreed with the simulated result within 5% of error, and the maximum antenna gain is 7.42㏈i.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.6 s.121
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• pp.591-601
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• 2007

In this paper, the miniaturized radio frequency identification(RFID) tag antennas used in UHF band$(908.5{\sim}914MHz)$ are designed and fabricated by using the circular loop antenna(CLA). Miniaturization of CLA was possible to transform the structure of circular loop into the structure of meander line. In the case of double meander line CLA is reduced up to 83% compared with the general type CLA. The $S_{11}$, -10 dB bandwidth, and gain of double meander line CLA were -11.9 dB, 12 MHz(1.3%), and -1.18 dBd. Also, a small half-wavelength CLA using double meander line is designed and fabricated for flat snack bag coated aluminum. The antenna is reduced up to 92.1% except ground. It shows the $S_{11}$ of -16.5 dB, -10 dB bandwidth of 48 MHz(5%) and gain of -0.58 dBd. The radiation pattern shows omni-directional pattern in z-y plane(x-axis pol.). Through this result, we can confirm that miniaturized type CLAs using meander lines are suitable for miniaturized RFIB tag antennas with the UHF band.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.12
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• pp.2816-2822
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• 2014

In this paper, a wideband loop antenna for UWB applications is studied. The structure of the proposed wideband loop antenna is a circular loop antenna with appended circular sectors to obtain an ultra-wideband characteristic. The circular sectors are used instead of conventional triangular sectors to match with the 50 ohm feed line. Optimal design parameters are obtained by analyzing the effects of the gap between the circular sectors and the radius of the circular loop on the input reflection coefficient and gain characteristics. The optimized wideband loop antenna is fabricated on an FR4 substrate with a dimension of 41 mm by 41 mm. Experiment results show that the proposed antenna has a frequency band of 3.1-11.0 GHz for a VSWR < 2.25, which assures the operation in the UWB band. Measured gain ranges 1.3-5.3 dBi in the UWB band.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.71-72
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• 2015

본 논문에서는 CPW(Coplanar waveguide) 급전되는 평면 루프 슬롯을 2.45 GHz 대역 Wi-Fi용으로 소형화 설계하는 방법에 대해 연구하였다. 제안된 구조는 직사각형 형태의 CPW 급전 루프 슬롯 안테나를 기본형으로 하여 내부 패치에 슬롯을 좌우 대칭으로 여러 개 수직 방향으로 배치한 안테나이며, FR4 기판의 한 면에 인쇄된다. 여러 가지 파라미터 값들이 안테나의 특성에 미치는 영향을 관찰하고 기존 루프 슬롯 안테나를 소형화하는 방법에 대해 연구하였다. FR4 기판에 $80mm{\times}50mm$ 크기로 2.45 GHz 대역용으로 설계된 안테나의 특성을 시뮬레이션을 통해 분석하였다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.2
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• pp.30-37
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• 2013

An extended loop antenna, to be continued BLA(Branch Loop Antenna) in the previous volume, for the mobile handset is designed in this paper. It's introduced an ELA(Extended Loop Antenna) that is added extended loops to rectangular loop, and verified antenna performances for applying to mobile handset. Extended loops are located upside, left and right side of rectangular loop, and low resonance is obtained by the length of line. Multiple resonances are established by the extended loops, and obtained the desired service bands by the connection points and lengths. By the implementation and measurement for the multiband ELA, it's showed -3.0~-1.46dBi average gains with 50.15~71.41% efficiencies at CDMA/GSM frequency band, and -8.28~-1.7dBi average gains with 14.87~67.68% efficiencies at DCS/USPCS/WCDMA frequency band.