• Title, Summary, Keyword: K-band Attenuation

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Design and Fabrication of K-band Attenuation Standard (K-대역 감소량 표준기의 설계 및 제작)

  • Lee Joo-Gwang;Kim Jeong-Hwan;Kang Jin-Seob;Kang Tae-Weon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.17 no.4
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    • pp.387-392
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    • 2006
  • In this paper, measurement scheme and uncertainty estimation of the K-band attenuation standard fitted with 3.5 mm coaxial connectors are described. The standard comprises a build-up chain of four steps of power ratio mea-surement and operates in the frequency range of 18 GHz to 26.5 GHz. The nominal attenuation of each step is around 20 dB and total dynamic range is 80 dB. The expanded uncertainty of the overall system is 0.01 dB at the confidence level of approximately 95%.

Miniature Multilayer LTCC Bandpass Filter with Attenuation poles (감쇄극을 갖는 초소형 적층 LTCC 대역통과 필터)

  • Lee, Y.S.;Song, H.S.;Bang, K.S.;Kim, J.C.;Park, J.C.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.751-755
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    • 2003
  • In this paper, We proposed compact multi-layer LTCC (Low Temperature Cofired Ceramic) bandpass filter for Bluetooth module. A ${\lambda}/4$ coupled stripline resonators are designed, which composed of coupled strip-line section and loading capacitance. This resonator with a loading capacitor has slow-wave characteristics. Due to the slow-wave effect of the proposed resonator, it is possible to design and fabricate a compact bandpass filter with a wide upper stop band. Attenuation poles in the lower stop band are achieved using controlling of electro-magnetic coupling between resonators. Using multi-layer LTCC technology, we designed and fabricated band pass filter with a finite attenuation pole and wide upper stopband. The overall size of the filter is $1.2{\times}2.0{\times}1.0mm^3$.

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Improvement Noise Attenuation Performance of the Active Noise Control System Using RCMAC (RCMAC를 이용한 능동소음 제어시스템의 소음저감 성능개선)

  • Han, S.I.;Yeo, D.Y.;Kim, S.H.;Lee, K.S.
    • Journal of the Korea Society For Power System Engineering
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    • v.14 no.5
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    • pp.56-62
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    • 2010
  • In this paper, a recurrent cerebellar modulation articulation control (RCMAC) has been developed for improvement of noise attenuation performance in active noise control system. For the narrow band noise, a filter-x least mean square (FXLMS) method has bee frequently employed as an algorithm for active noise control (ANC) and has a partial satisfactory noise attenuation performance. However, noise attenuation performance of an ANC system with FXLMS method is poor for broad band noise and nonlinear path since it has linear filtering structure. Thus, an ANC system using RCMAC is proposed to improve this problem. Some simulations in duct system using harmonic motor noise and KTX cabin noise as a noise source were executed. It is shown that satisfactory noise attenuation performance can be obtained.

UHF Sensor Location Optimization for Partial Discharge Signals Detection Method (UHF 센서 위치 최적화로 부분방전 신호 검출 방법)

  • Choi, Mun-Gyu;Cha, Hanju
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.3
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    • pp.409-413
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    • 2014
  • GIS partial discharge that occurred in the UHF band signal is effectively detected by the method to IEC60270 5pc the apparent minimum discharge can be detected over the GIS arrangement of the sensor interior and exterior of the UHF in accordance with the optimized position signal by considering the damping ratio is selected so that the signals can be obtained to be mounted. 362kV, 800kV GIS is installed on the internal and external sensors are UHF band signal attenuation is set by measuring the reference value, but the operation, 170kV case 362kV, 800kV on the basis of the measurement data and to be installed and operated. When 170kV per 1Bay by installing the built-in sensor 1 for detecting a partial discharge signal, But, GIS signal attenuation is large in the case of an internal partial discharge signal is not detected in some cases. Where the attenuation is great UHF signal of the sensor by increasing the quantity of partial discharge signals were acquired to allow relocation. The greater the spacing between the sensor and the sensor is applied simplifies the installation and reduces the cost in terms of maintenance of appropriate optimal position is calculated to detect the partial discharge signal is needed. Thus 170kV GIS signal power attenuation of a partial discharge by measuring the UHF sensor, and by relocating the proper position is calculated in accordance with the sensor signal decay rate and minimize the error of omission in detecting a partial discharge signal was optimized.

High frequency P velocity and attenuation coefficient of the rocks under the broad-band seismic station (광대역 관측소 하부 암석의 고주파수 탄성파 속도 및 감쇠상수에 대한 연구)

  • Lee, Duk-Kee;Oh, Seok-Hoon;Youn, Yong-Hoon;Yang, Jun-Mo
    • Journal of the Korean Geophysical Society
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    • v.5 no.3
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    • pp.165-174
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    • 2002
  • Seismic velocity and attenuation coefficient of the rocks under the broad-band earthquake observatories of the Korea Meteorological Administration have been measured in the laboratory by using very high frequency seismic waves. Estimated P velocities of the rocks range from 3.2 km/s to 5.6 km/s, depending on the rock type, mineral, and weathering, while, the attenuation coefficients vary from 0.06 to 4.3 db/kHz-m. It seems that P velocities is inversely proportional to the attenuation coefficients of the rocks. Average travel-time delays of the broad-band stations seem to be related with the measured P velocities in the laboratory.

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Attenuation Effects of Plasma on Ka-Band Wave Propagation in Various Gas and Pressure Environments

  • Lee, Joo Hwan;Kim, Joonsuk;Kim, Yuna;Kim, Sangin;Kim, Doo-Soo;Lee, Yongshik;Yook, Jong-Gwan
    • Journal of electromagnetic engineering and science
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    • v.18 no.1
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    • pp.63-69
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    • 2018
  • This work demonstrates attenuation effects of plasma on waves propagating in the 26.5-40 GHz range. The effect is investigated via experiments measuring the transmission between two Ka-band horn antennas set 30 cm apart. A dielectric-barrier-discharge (DBD) plasma generator with a size of $200mm{\times}100mm{\times}70mm$ and consisting of 20 layers of electrodes is placed between the two antennas. The DBD generator is placed in a $400mm{\times}300mm{\times}400mm$ acrylic chamber so that the experiments can be performed for plasma generated under various conditions of gas and pressure, for instance, in air, Ar, and He environments at 0.001, 0.05, and 1 atm of pressure. Attenuation is calculated by the difference in the transmission level, with and without plasma, which is generated with a bias voltage of 20 kV in the 0.1-1.4 kHz range. Results show that the attenuation varies from 0.05 dB/m to 9.0 dB/m depending on the environment. Noble gas environments show higher levels of attenuation than air, and He is lossier than Ar. In all gas environments, attenuation increases as pressure increases. Finally, electromagnetic models of plasmas generated in various conditions are provided.

Analysis of C/N Variation of Ku Band Satellite Beacon Receiver According to Rain Attenuation (강우 감쇠에 따른 Ku 대역 위성 비콘 수신기 C/N 변화 해석)

  • Park, Dae-Kil;Lee, Kyung-Soon;Koo, Kyung Heon
    • The Journal of Advanced Navigation Technology
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    • v.22 no.5
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    • pp.415-419
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    • 2018
  • This paper predicts and measures the C/N ratio of a beacon signal transmitted from geostationary orbit satellite KorSat 5A ($113^{\circ}E$) at a ground station located in Kimpo. Based on the ground stations, we compared the rain attenuation of the zone K of ITU-R and the rain attenuation which analyzed the domestic weather information. In ITU-R, the Korean rainfall characteristics are classified into zone K, but forecasting the rainfall intensity and attenuation of three adjacent cities based on the cumulative rainfall data per minute from 2013 to 2017. The calculation of rainfall path and attenuation is based on ITU-R recommendations. The change of the C/N according to the rainfall amount was confirmed through the 2 week satellite beacon signal C/N measurement. The predicted critical C/N was decreased to 12 dB at $A_{0.3}$. During the experiment, it was confirmed that it decreased up to 8 dB according to the concentrated rainfall.

Design and fabrication of multilayer LTCC BPF using Combline structure (Combline 구조를 이용한 적층 LTCC 대역통과 필터의 설계 및 제작)

  • An, S.Y.;Lee, Y.S.;Bang, K.S.;Kim, K.C.;Kang, N.K.;Song, H.S.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.628-631
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    • 2003
  • In this paper, 2.4 GHz WLAN BPF(Band Pass Filter) using LTCC(Low temperature cofiring ceramic) multilayer technology was simulated and manufactured. A modified ${\lambda}/4$ Hair-pin resonator with shunt-to ground loaded capacitor is used to shorten resonator length and improve circuit Q factor. Proposed BPF has a combline structure. Electro-magnetic Coupling between coupled strip-line resonators is controlled to provide attenuation poles at finite frequencies. The overall size of the filter is $3.2{\times}1.6{\times}1.3mm^3$. The measured result shows good agreement with simulated data.

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Improved Plasmonic Filter, Ultra-Compact Demultiplexer, and Splitter

  • Rahimzadegan, Aso;Granpayeh, Nosrat;Hosseini, Seyyed Poorya
    • Journal of the Optical Society of Korea
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    • v.18 no.3
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    • pp.261-273
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    • 2014
  • In this paper, metal insulator metal (MIM) plasmonic slot cavity narrow band-pass filters (NBPFs) are studied. The metal and dielectric of the structures are silver (Ag) and air, respectively. To improve the quality factor and attenuation range, two novel NBPFs based on tapered structures and double cavity systems are proposed and numerically analyzed by using the two-dimensional (2-D) finite difference time domain (FDTD) method. The impact of different parameters on the transmission spectrum is scrutinized. We have shown that increasing the cavities' lengths increases the resonance wavelength in a linear relationship, and also increases the quality factor, and simultaneously the attenuation of the wave transmitted through the cavities. Furthermore, increasing the slope of tapers of the input and output waveguides decreases attenuation of the wave transmitted through the waveguide, but simultaneously decreases the quality factor, hence there should be a trade-off between loss and quality factor. However, the idea of adding tapers to the waveguides' discontinuities of the simple structure helps us to improve the device total performance, such as quality factor for the single cavity and attenuation range for the double cavity. According to the proposed NBPFs, two, three, and four-port power splitters functioning at 1320 nm and novel ultra-compact two-wavelength and triple-wavelength demultiplexers in the range of 1300-1550 nm are proposed and the impacts of different parameters on their performances are numerically investigated. The idea of using tapered waveguides at the structure discontinuities facilitates the design of ultra-compact demultiplexers and splitters.

Analysis of Ka Band Satellite Link Budgets and Earth Station G/T in Korea Rainfall Environment (국내 강우 환경에서 Ka 밴드 위성 링크 버짓 및 지구국 G/T 분석)

  • Choi, Hyeong-Jae;You, Kyoung-A;Park, Dae-Kil;Koo, Kyung Heon
    • The Journal of Advanced Navigation Technology
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    • v.23 no.2
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    • pp.151-157
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    • 2019
  • In geostationary satellite communications, which are widely used for broadcasting and communication, there is a path loss where the signal power on the path is largely reduced. It is important to consider rain attenuation when calculating link budget because the Ka band frequency is vulnerable to rain attenuation. In this study, rainfall trends were analyzed by using rainfall data from the year 2000 in four regions of Korea (Seoul, Incheon, Busan, Jeju) and the rainfall attenuation was calculated. This was used to analyse the satellite link budget and receiving performance for the down-link of the korea satellite COMS. In this study, the calculated G/T for the rainfall intensity of 0.5% per year using the rainfall data for 18 years increased by approximately $8.5dBK^{-1}$ compared to the ITU's zone-K rain model, and decreased by approximately $1dBK^{-1}$ compared to the precipitation data for 13 years from the TTA(Korea Telecommunications Technology Association). The results of this study can be used for the design of G/T in domestic-installed satellite ground station.