• Title/Summary/Keyword: Solid Surface Antenna

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Effects on Performance of Deployable Solid Antenna for Panel Misalignment (패널오차에 의한 전개형 솔리드 안테나 성능 영향)

  • Lee, Ji-Yong;Lee, Kyo-Il;Yoon, Seong-Sik;Lee, Taek-Kyung;Lee, Jae-Wook
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.28 no.8
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    • pp.603-609
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    • 2017
  • In the deployable solid surface antennas, the effects on the performances of antenna due to the structural errors that occur during the deployment are analyzed. The deployable solid surface antennas employed in a satellite are launched in folded configuration and those are deployed in the space environment, and the effects on the antenna performance are calculated depending on the type of surface errors. When the deviation error occurs in one panel, the degradation of performance appears in the side where the incomplete deployment of panel occurs. By assuming that the panel error distribution is in cosine function, the effect of errors are calculated and analyzed with regard to the types and the magnitude of the error. If the antena panel error is uniform, the gain is reduced and pattern is symmetric. For the panel error of cosine 1 or 3 cycle, the main lobe tilts while the pattern is symmetric and the gain reduces for 2 or 4 cycle error.

The Frequency Characteristics of Electromagnetic Waves and Discharge Phenomena Caused by Polluted Condition of Solide Insulator Surface (고체절연체표면의 오염상태에 따른 방전현상과 방사전자파의 주파수 특성)

  • 김충년;박원주;이광식;이동인;김인식
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.15 no.4
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    • pp.43-50
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    • 2001
  • In this paper, the discharge phenomena and electromagnetic waves caused by discharge with insertion of a solid insulator and flame between sphere-sphere electrodes in air ware investigated. The surface discharge light and patterns of flame generated on a solid insulator surface were observed by using a CCD(Charged Coupled Device) camera. Also, the radiated electromagnetic waves were measured by using a biconical antenna and a spectrum analyzer. The surface discharge light generated on the solid insulator surface was larger and the size of flame was smaller by increasing allied voltages. Also, voltage distortion by voltage drop was strongly revealed when a insulator surface was polluted. When a solid insulator surface was not polluted, the electric field stength of electromagnetic waves was 10∼17[dBuV/m] higher than a polluted solide insulator, and 5∼9[dBuV/m] higher than a polluted solide insulator and flame.

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High Transparent Planar Dipole Antenna using Ionized Salt-water of ASA Structure (이온화된 소금물을 이용한 ASA 구조의 고 투명 평면형 다이폴 안테나)

  • Phan, Duy Tung;Jung, Chang Won
    • 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.

THE EFFECT OF SURFACE METEOROLOGICAL MEASUREMENTS ON PRECISION GPS HEIGHT DETERMINATION

  • Wang Chuan-Sheng;Liou Yuei-An;Wang Cheng-Gi
    • Proceedings of the KSRS Conference
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    • 2005.10a
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    • pp.178-181
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    • 2005
  • The positioning accuracy of the Global Positioning System (GPS) has been improved considerably during the past two decades. The main error sources such as ionospheric refraction, orbital uncertainty, antenna phase center variation, signal multipath, and tropospheric delay have been reduced substantially, if not eliminated. In this study, the GPS data collected by the GPS receivers that were established as continuously operating reference stations by International GNSS Service (IGS), Ministry of the Interior (MOl), Central Weather Bureau (CWB), and Industrial Technology Research Institute (ITRI) Of Taiwan are utilized to investigate the impact of atmospheric water vapor on GPS positioning determination. The surface meteorological measurements that were concurrently acquired by instruments co-located with the GPS receivers include temperature, pressure and humidity data. To obtain the influence of the GPS height on the proposed impact study. A hydrodynamic ocean tide model (GOTOO.2 model) and solid earth tide were used to improve the GPS height. The surface meteorological data (pressure, temperature and humidity) were introduced to the data processing with 24 troposphere parameters. The results from the studies associated with different GPS height were compared for the cases with and without a priori knowledge of surface meteorological measurements. The finding based on the measurements in 2003 is that the surface meteorological measurements have an impact on the GPS height. The associated daily maximum of the differences is 1.07 cm for the KDNM station. The impact is reduced due to smoothing when the average of the GPS height for the whole year is considered.

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The Measurement of Electromagnetic Waves caused by Surface Discharges of Solide Insulator at VHF Band Using an Antenna (안테나를 이용한 VHF대역에서 고체절연체의 연면방전에 기인한 방사전자파의 측정)

  • Kim, Ch.N.;Park, K.S.;Kim, K.C.;Lee, K.S.;Lee, D.I.
    • Proceedings of the KIEE Conference
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    • 2001.11a
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    • pp.219-223
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    • 2001
  • In this paper, electromagnetic waves were measured in accordance with propagating the discharge when positive and negative DC high voltage was applied to needle-plane electrdes and plane-plane electrdes that solid dielectric was inserted between the electrodes. The radiated electromagnetic waves were investigated in bandwidth of VHF($30{\sim}230$[MHz]) using an biconical antenna. In needle-plane electrodes high electric field intensity is shown in both frequency band of 90(MHz) and 170[MHz], and gradually decreasing characteric is appeared at high frequency band. However high electric field intensity is shown in both 80[MHz] and 140[MHz] in case of plane-plane electrodes configuration. And over 150[MHz] frequency band, rapidly decreasing characteristic is shown. Moreover, electric field intensity of positive DC is about $5{\sim}10$[dB] higher than negative DC.

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Study on Insulation Diagnosis of Poor Contact between Electrode and Solid Insulator in Eco-Gas (친환경 가스 중 전극과 고체절연체의 불량접촉에 관한 절연진단연구)

  • Lim, Dong-Young;Choi, Eun-Hyeok;Bae, Sungwoo;Choi, Sang-Tae;Lee, Kwang-Sik;Choi, Byoung-Ju
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.10
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    • pp.97-103
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    • 2015
  • This paper presents the characteristics of partial discharge and radiated electromagnetic waves in the existence of a poor contact for the insulation diagnosis of eco-friendly power equipment. AC surface discharge experiment was conducted to simulate the poor contact between a hive voltage electrode (anode) and a solid insulator in $N_2/O_2$ mixture gas under a non-uniform field. The partial discharge voltage to be measured at 0.3MPa increased with the increase of the poor contact gap and was saturated with the gap. In addition to the partial discharge characteristics, it was verified that the defect of the poor contact can be diagnosed using the radiated electromagnetic waves due to the partial discharge, which measured by a biconical EMC antenna and a spectrum analyzer.