• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.5
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• pp.459-467
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• 2010

A new type of circularly polarized(CP) antenna that is characterized by having both low-profile and greater axial-ratio bandwidth(ARBW) beyond existing antennas is introduced through analysis of artificial magnetic conductor(AMC) polarizer, and experimentally demonstrated. Although it is made use of a linear-polarized dipole antenna with close proximity to ground plane, it is backed by AMC polarizer so as to efficiently radiate with circularly changed polarization whose ARBW is determined by the texture geometry, whereas existing antennas exhibit CP surface-current on radiators, which limit ARBW. The mechanism of the polarization conversion is theoretically analyzed for ARBW, and the experimental properties including the impedance matching, CP radiation pattern, axial-ratio pattern, ARBW, and two-port isolation are discussed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.5
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• pp.747-756
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• 1999

In this paper, we analyzed microwave-DC conversion efficiency for the dual-polarization rectenna and antenna position changing. And then we analyzed and applied Square-Loop FSS structure for reducing the diode harmonic components as a rectifying circuit. The results of microwave-DC conversion efficiency for the each of designed dual-polarization rectenna has 69.1% with $360\Omega$ (dipole type) and 75.4% with $340\Omega$ (patch type) optimum load resistor. When the each of dual-polarization rectenna has a optimal load resistor, it's conversion efficiency shows of $\pm$20% in dipole type and $\pm$5% in patch type at $0~180^{\circ}$position. When applied Square-Loop FSS structure for Rectenna, Insertion loss was under 1 dB as the passband and over 20 dB as the stopband. The microwave -DC conversion efficiency was represented good properties of $\pm$2% variation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.939-940
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• 2015

In this paper, a design method for a quasi-Yagi antenna (QYA) suitable for UHF band is studied. Due to the mutual coupling between a coplanar strip (CPS)-fed planar dipole and a conducting strip director placed close to the dipole, the dipole obtains broadband characteristics. A ground reflector improves gain in the lower frequency band, and the antenna size might be reduced by employing a bent reflector. The balun between the CPS line and the microstrip(MS) line is constructed by connecting the end of MS line and the CPS line through a shorting pin. In addition, a ring-type conductor connects the CPS line and reflector. The effects of various geometrical parameters and balun on the antenna characteristics are examined. An antenna, as an design example for the proposed antenna, is designed for the operation in the frequency band of 470-806 MHz for terrestrial DTV.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.2
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• pp.21-26
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• 2022

In this paper, we investigated the effect of tilting and bending of an 2.45GHz ISM band embroidered dipole array antenna due to the human body movement. The antenna characteristics showed larger variations in tilting on the X-axis than the Y-axis. The antenna gain varied by 0.25[dB] when the antenna tilted by 3.5°. As tilting angle increased the operating frequency(f_o) showed decreasing tendency and the return loss(S₁₁) showed increasing tendency. The antenna characteristics also showed more variation in bending on the X-axis than the Y-axis. As bending the antenna the antenna characteristics affected much more in bending on the X-axis than the Y-axis. The antenna gain varied by 3.73[dB] as the curvature(1/R_rad) increased by 0.04[mm^-1]. As it bended more the operating frequency(f_o) showed decreasing and then increasing tendency and the return loss(S₁₁) showed increasing tendency.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.6
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• pp.958-964
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• 2001

In this paper, we propose a novel wide band printed monopole antenna called the staircase bow-tie monopole antenna (SBMA). We apply an extraordinary method for an impedance matching to conventional bow-tie monopoles. So we get the SBMA with a very wide band. Our antenna is smaller than a quarter wavelength in size but provides a 2:1 VSWR bandwidth of about 77.1 %. An antenna gain and a radiation pattern are about 1.7 dBi and omni-directional at 1.7 GHz, respectively.

• Proceedings of the KAIS Fall Conference
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• 2005.05a
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• pp.177-179
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• 2005

본 논문에서는 지상파 UHF 휴대용 슬리브 안테나를 설계 제작하였다. 이 안테나는 차량 네비게이션장치에 들어가는 지상파 UHF TV 수신을 위한 안테나이다. 기존 모노폴 형태가 갖는 단점을 제거하고 성능 향상을 위해 세트 external 안테나로, 필요시에 목걸이형으로 부착이 가능한 구조를 가지고 있다. 동축선을 이용하여 슬리브 다이폴 안테나로 설계함으로써 안테나 입장에서 볼 때 접지가 부족한 문제를 해결하였다. 제작 측정한 결과 UHF 대역에서 VSWR 2:1 이하의 특성을 만족하였다.

• Journal of the Korea Knowledge Information Technology Society
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• v.12 no.4
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• pp.539-550
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• 2017

In this paper, we designed, fabricated and tested an UHF band cylindrical dipole array antenna. In the proposed antenna, cylindrical dipoles were vertically arranged in four stages. A parallel structure feeding circuit was installed inside the cylindrical dipole and mounted so as to be broadband matching. The feeding circuit was installed at the center of the cylindrical dipole to optimize the gain flatness characteristic of the azimuth direction omnidirectional radiation pattern. Minimizing the difference between the signals branched from the feeding circuit and realizing the symmetry of the radiation pattern. The required specifications are more than 11.2% bandwidth in UHF band, above 6dBi antenna gain, standing wave ratio of 2:1 or less, less than ${\pm}1dB$ gain flatness in azimuth radiation pattern, more than 13 degrees in elevation radiation pattern of 3dB beamwidth. We confirmed the possibility of implementation through M&S and verified the result of M&S through production and testing. The test results are 11.2% bandwidth in the UHF band, 6.30 to 8.31 dBi gain, 1.53:1 standing wave ratio or less, within ${\pm}0.2dB$ gain flatness in the azimuth radiation pattern, elevation radiation pattern of 3dB beam width was 15.62 to 15.84 degrees. The test result meets all requirements specifications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.4
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• pp.1908-1914
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• 2013

In this paper, we introduce a design method for a broadband planar quasi-Yagi antenna (QYA) for terrestrial digital television (DTV) reception. The coplanar strip line which feeds the driver dipole is connected to a microstrip line and is terminated by short circuit. By appending a wide strip-type rectangular director at a location close to the driver dipole, broadband impedance matching and gain enhancement in a high frequency region are obtained. The gain characteristics in a low frequency region are improved by adding a reflector formed by a truncated ground plane. To reduce the antenna size, the strip-type dipole and reflector are modified to half bow-tie (V)-shaped elements. The effects of various parameters on the antenna characteristics are examined. An antenna, as a design example for the proposed antenna, is designed for the operation in the frequency band of 470-806 MHz for terrestrial DTV. The optimized antenna is fabricated on an FR4 substrate and the experimental results show that the antenna has a good performance such as a frequency band of 450-848 MHz for a VSWR < 2, gain > 4.1 dBi, and front-to-back ratio > 10.4 dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.10
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• pp.883-891
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• 2016

In this paper, we propose an asymmetric dipole antenna utilizing the metal case as a ground radiator for a pen-type wireless presenter which operates in the ISM frequency band(2.4~2.48 GHz). A normal mode helix mounted on the top end of the long metallic cylinder case which acts as the ground plane takes the form of the asymmetric dipole structure in the proposed antenna. The metallic cylinder case which performs as a radiating element increases the inherent narrow bandwidth and low gain of the helix. The effects of the hand contacts with the metal case on the antenna performance are measured and analyzed with a specially designed human phantom. Experimental results show that the -10 dB return loss bandwidth of the proposed antenna in free space(no hand contact) is 200 MHz that ranges from 2.3 to 2.5 GHz and the maximum gain is measured to be 5 dBi. Under the normal operating condition where the metal case is contacted with a human hand, the bandwidth is 480 MHz from 2.24 to 2.72 GHz. The maximum gain is 2 dBi, lowered by 3 dB due to the hand contact.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.492-498
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• 2021

This feasibility study evaluated an optically transparent planar antenna using liquid salt-water as the conducting material. The most significant reason behind using liquid salt-water for transparent antenna applications is its excellent average optical transparency (OTav) (> 95% at a salinity of 40 ppt) compared to other typical solid transparent thin-film electrodes, such as indium tin oxide (ITO:> 73%) or multi-layer films (MLF: > 78%). Each conductive arm of the proposed dipole is constructed from a salt-water layer held between two clear planar acrylic layers (��r = 2.61, tan�� = 0.01, OTav > 90%) (acrylic/salt-water/acrylic; ASA) due to surface tension. To examine the electrical and optical properties of the ASA structure, the surface tension was measured to determine the thickness of the salt-water layer that finalized its sheet resistance and OTav. The average gain and efficiency of the antenna were 1.72 dBi and 74%, respectively, in the operating UHF (Ultra high frequency) band (470-771 MHz). Therefore, the proposed antenna can be a good candidate for applications as a transparent planar antenna using salt-water.