• Title/Summary/Keyword: Conductive BM

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Study of the Electro-Optic Characteristics Depending on Electric Characteristic of the Black Matrix in a Homogeneous Liquid Crystal Cell Driven by Fringe-Electric Field (프린즈 전기장에 의해 구동되는 수평 배향 액정셀에서 black matrix의 전기적 특성이 셀의 전기광학 특성에 미치는 영향에 관한 연구)

  • 김미숙;김향율;고재완;이승희
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.16 no.11
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    • pp.1008-1013
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    • 2003
  • We have studied the effect of black matrix (BM) according to the dielectric anisotropy of liquid crystals (LCs) for a homogeneously aligned LC cell driven by fringe-electric field. The results show that for a LC with positive dielectric anisotropy (+LC) there is a large transmittance change when using a conductive BM, whereas the transmittance change is low for a LC with negative dielectric anisotropy (-LC). The conductive BM existing on top substrate produces vertical electric field, which makes the LC molecules be tilt upward from the substrate and have small twist angle for the +LC. However, for the -LC the conductive BM affects the LC distribution only slightly due to characteristic of the -LC orienting perpendicular to the field. Therefore, for the +LC the electro-optic characteristics are strongly dependent on conductivity of the BM on top substrate in a homogeneous liquid crystal cell driven by fringe-electric field.

RFID Tag Antenna Mountable on High-Conductivity and High Permittivity an Materials at UHF Band (고 전도율과 고 유전율 물질에 부착 가능한 RFID 태그 안테나)

  • Kwon Hong-Il;Lee Bom-Son
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.16 no.8 s.99
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    • pp.797-802
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    • 2005
  • In this paper, we design a UHF band RFID tag antenna which is conjugate matched to an impedance of a chip and also mountable on conductive materials. The proposed tag antenna is very compact($50{\times}30{\times}4mm$) with a modified PIFA shape. The proposed tag antenna has an advantage of easy matching to various chip input impedances. The performance of the antenna is evaluated by monitoring RCS in the reader direction. The RCS of the designed tag is $-10.2\;dBm^2$ when the chip is shorted and is $-21\;dBm^2$ when the chip impedance is a complex conjugate of the antenna impedance.

A Study of Electromagnetic Interference in Power Line Communication (전력선 통신에서의 전자파 장해에 관한 연구)

  • Lee Jin-Taek;Chun Dong-Wan;Park Young-Jin;Lee Won-Tae;Shin Chul-Chai
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.53 no.12
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    • pp.620-625
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    • 2004
  • In this paper, we studied the emissive electric field due to the communication signal and the noise in medium voltage power-line. There are many types of conductive noise in power-line channel, which gives rise to radiation. And if the DMT carrier signal was excited, the current by this term was added to the current by noise and, generate radiation. We calculated input impedance by means of signal input network model of medium voltage power-line channel for calculating these currents. We calculated currents by input impedance and, calculated the emissive electric field by this calculated currents. From the measurement results, we knew that the measured results are very similar to the calculated results and if the input signal power level was higher than -40 dBm, the emissive electric field exceeds FCC radiation limit level 69.5 dB$\mu$V/m.

A Fully-integrated Ku/K Broadband Amplifier MMIC Employing a Novel Chip Size Package (새로운 형태의 CSP를 이용한 완전 집적화 Ku/K밴드 광대역 증폭기 MMIC)

  • Yun, Young
    • Journal of Navigation and Port Research
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    • v.27 no.2
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    • pp.217-221
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    • 2003
  • In this work, we used a novel RF-CSP to develop a broadband amplifier MMIC, including all the matching and biasing components, for Ku and K band applications. By utilizing an ACF for the RF-CSP, the fabrication process for the packaged amplifier MMIC could be simplified and made cost effective. STO (SrTiO$_3$) capacitors were employed to integrate the DC biasing components on the MMIC. A pre-matching technique was used for the gate input and drain output of the FETs to achieve a broadband design for the amplifier MMIC. The amplifier CSP MMIC exhibited good RF performance (Gain of 12.5$\pm$1.5 dB, return loss less than -6 dB, PldB of 18.5$\pm$1.5 dBm) over a wide frequency range. This work is the first report of a fully integrated CSP amplifier MMIC successfully operating in the Ku/K band.