• Title/Summary/Keyword: 임피던스미터

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Traveling-wave Ti:LiNbO3 optical modulator capable of complete switching (완전 스위칭이 가능한 Ti:LiNbO3 진행파 광변조기)

  • 곽재곤;김경암;김영문;정은주;피중호;박권동;김창민
    • Korean Journal of Optics and Photonics
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    • v.14 no.5
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    • pp.545-554
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    • 2003
  • Design of the optical modulator composed of a three-waveguide coupler and CPW traveling-wave electrodes was carried out. Switching phenomena of three-waveguide couplers were analyzed by using the coupled mode theory, and the coupling-lengths of the devices were calculated by means of the FDM. CPW traveling-wave electrodes were analysed by the CMM and SOR simulation technique in order to find the conditions of phase-velocity and impedance matching. Traveling-wave modulators were fabricated on z-cut LiNbO$_3$ substrate. Ti was in-diffused in LiNbO$_3$ to make waveguides and Au electrodes were built on the waveguides by the electrolyte technique. The fabricated modulator chip was end-polished, pig-tailed and packaged in a brass mount with K-connector. The insertion loss and the switching voltage of the optical modulator were about 4㏈ and 19V, respectively. Network analyzer was used to obtain the S parameter and the corresponding RF response. From the measurement, parameters of the traveling-wave electrodes were extracted to be Z$_{c}$= 45 Ω, N$_{eff}$=2.20, and $\alpha$$_{0}$=0.055/cm√GHZ. The measured optical response R($\omega$) was compared with the theoretically estimated one, showing both responses agree well. The measurement results revealed that 3㏈ bandwidth turned out to be about 13 GHz.

Low-cost Impedance Technique for Structural Health Monitoring (임피던스 기반 저비용 구조물 건전성 모니터링 기법)

  • Lee, Jong-Won
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.12
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    • pp.265-271
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    • 2018
  • This paper presents a method for detecting damage to a structure at low cost using its impedance. The impedance technique is a typical method to detect local damage for structural health monitoring. This is a common technique for estimating damage by monitoring the electro-mechanical admittance signal of the structure. To apply this technique, an expensive impedance analyzer is generally used. On the other hand, it is necessary to develop a low-cost variant to effectively disseminate the technique. In this study, a method based on the transfer impedance using a function generator and digital multimeter, which are generally used in the laboratory instead of an impedance analyzer, was developed. That is, this technique estimates the damage by comparing the damage index using the amplitude ratio of the output voltage measured in the healthy and damaged state. A transfer impedance test was carried out on a steel specimen. By comparing the damage index, the presence of damage could be assessed reasonably. This study is a basic investigation of an impedance-based low-cost damage detection method that can be used effectively for structural health monitoring if supplemented with future research to estimate the damage location and severity.

Bias-Dependent Data Extraction of Gate Impedance Model Parameters for RF MOS Transistors (RF MOS 트랜지스터를 위한 게이트 임피던스 모델 파라미터의 바이어스 종속 데이터 추출)

  • Choi Munsung;Lee Yongtaek;Ku Janam;Lee Seonghearn
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.42 no.5 s.335
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    • pp.1-8
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    • 2005
  • A RC parallel gate model is used to consider gate distributed effect that affects RF MOSFET performance, and extraction formula based on $Y_{11}$-parameters are used to extract model parameters directly from measured S-parameters. Better agreement between measured and modeled S-parameters in the frequency range beyond 10 GHz is achieved by using the RC parallel model than conventional Rg one, demonstrating the accuracy of the RC model and extraction technique. Using these extraction methods, gate voltage dependent curves of RC gate model parameters are newly extracted, and these parameter data will greatly contribute to developing a RF nonlinear gate model.

CDN을 이용한 전자파 전도내성시험의 측정불확도

  • Mun Jun-Cheol;Im Yeong-Chae
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.16 no.4 s.56
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    • pp.84-92
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    • 2005
  • 본 논문은 CDN(Coupling/Decoupling Network)을 이용한 전자파 전도 내성 시험의 측정 불확도를 연구하였다. 측정 불확도의 영향 인자를 추출하여 인자별 불확도를 산출하였다. 측정 불확도 인자는 인가 레벨 교정시 반복 측정, $150\sim50\Omega$ 아답터의 삽입 손실, 신호 발생기의 정확도, 파워미터의 정확도, 전력 증폭기의 하모닉, 전력 증폭기와 CDN의 부정합, CDN과 파워미터 사이의 부정합에 의한 불확도를 고려하였다. 불확도 산출 결과 확장 불확도는 95% 신뢰 구간에서 1.17 dB(k=)를 가지며, 정보기기의 경우 시험 전압 3 V에서 ${\pm}0.42V$의 오차 범위를 가지는 것을 알 수 있었다. 또한 시험기기간의 부정합에 의한 불확도가 불확도 인자에서 가장 큰 영향을 미치는 것을 알 수 있었으며, 전자파 전도 내성 시험의 경우 임피던스 매칭이 가장 중요한 것으로 나타났다.

Design of Electrodes of the Tapered Region of the Traveling-Wave Optical Modulator: SOR Method (진행파 광변조기의 Taper영역 전극 설계 : SOR기법)

  • 정석원;김창민
    • Korean Journal of Optics and Photonics
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    • v.7 no.1
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    • pp.77-86
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    • 1996
  • We employ the SOR method to analyze CPW electrodes of Ti:$LiNbO_3$ Mach-Zehnder traveling-wave optical modulator in the tapered region of an optical modulator. In the tapered region of the modulator, we design the electrodes satisfying $Z_c=50{\Omega}$. In the modulation region, we find two find sets of design parameters. One set is for $Z_c=50{\Omega}$, $n_{eff}=2.26$ and the another is for $n_{eff}=2.2$, $Z_c=47.7{\Omega}$.

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Microstrip patch antenna using 3 dimensional microstrip transition (3차원 천이를 이용한 마이크로스트립 패치 안테나)

  • 박동국;최형동
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.5 no.4
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    • pp.817-821
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    • 2001
  • In this paper, we design a microstrip patch antenna using 3-dimensional microstrip transition with the VSWR 1.3 over the PCS band (1.75 -1.87 GHz). We study experimentally the effect of the antenna parameters on antenna input impedance. And using the proposed antenna, we fabricate a polarization diversity any antenna and discuss the possibility of antenna for PCS base station.

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Enhanced Parameter Measurement Method of Battery 2nd RC Ladder Model (배터리 2차 RC Ladder 모델 변수 측정법 개선)

  • Kim, Jae-Gu;Lim, Dong-Jin;Ahn, Jung-Hoon;Lee, Byoung-Kuk
    • Proceedings of the KIPE Conference
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    • 2015.07a
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    • pp.451-452
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    • 2015
  • 본 논문은 리튬 폴리머 배터리 전기적 등가 회로 모델의 정확도 향상을 위하여 내부 파라미터를 결정하는 개선된 방법을 제안한다. 종래의 파라미터 결정 방법이 내부 용량성 임피던스의 영향으로 부정확해지는 현상을 분석하고, 해결방안을 제시한다. 제안하는 방법으로 얻어진 배터리 모델의 정확성은 시뮬레이션 결과 및 단전지의 실험적 결과를 통하여 검증한다.

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A RF Modeling Technique of Accumulation Mode Varactor (축적형 버랙터의 RF 모델링 기법)

  • 김지활;이승엽;홍승호;정윤하
    • Proceedings of the IEEK Conference
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    • 2003.07b
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    • pp.699-702
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    • 2003
  • 본 논문에서는 주파수 1∼7GHz 에서 게이트 바이어스가 □ 2.0 ∼ 2.0 V 일때 사용 가능한 축적형 버랙( accumulation mode varactor )의 RF 모델링 기법을 제안하였다. 기존의 모델링 기법은 가변 커패시터가 존재하는 부분에서 임피던스의 실수성분이 일정한 값을 가지는 것으로 모델링 하였으나 소자의 측정결과를 통하여 실수성분이 일정한 값이 아닌 주파수에 따라 변화하는 값임을 알았다. 이를 설명하기 위해서 기존의 모델링 기법에 커패시터와 저항을 하나씩 추가하여 새로운 모델을 구성하고 각각의 파라미터를 추출하였다.

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Studies on the Concrete Reinforcement Corrosion by Electrochemical Impedance Spectroscopy (전기화학적 임피던스법에 의한 철근콘크리트의 부식연구)

  • Kang, Tae-Hyuk;Cho, Won-Il;Cho, Byung-Won;Ju, Jeh-Beck;Yun, Kyung-Suk
    • Applied Chemistry for Engineering
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    • v.9 no.6
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    • pp.907-913
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    • 1998
  • Corrosion behavior of steel reinforcements embedded in concrete containing various chloride ion concentrations was investigated by an electrochemical impedance spectroscopy(EIS). Chloride ions were introduced into the concrete by dissolving the NaCl and $CaCl_2$ in the water with a given weight of cement. Based on the impedance parameters measured by EIS, more complete equivalent circuit, a schematic physical model, and the mechanism of concrete reinforcement corrosion were suggested. By the implement of experimental impedance parameters obtained from the model with corresponding CNLS-fitting data, the corrosion rate of steel reinforcement with chloride ions could be predicted.

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Impedance Characteristics of the Gel Type VRLA Battery at the Various State-of-Charge (겔식 납축 전지의 충전상태에 따른 임피던스 특성 연구)

  • An, Sang-Yong;Jeong, Euh-Duck;Won, Mi-Sook;Shim, Yoon-Bo
    • Journal of the Korean Electrochemical Society
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    • v.11 no.1
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    • pp.33-36
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    • 2008
  • In the present study, impedance spectrometry has been used for predicting State-of-Charge (SoC) of gel type, Valve Regulated Lead Acid (VRLA), battery. The impedance measurements of VRLA battery (2V/1.2 Ah) at various SoC were made over the frequency range from 100kHz to 10mHz with an amplitude 10 mV. The impedance parameters have been evaluated by the analysis of the data using an equivalent circuit and a complex non-linear least squares (CNLS) fitting method. The charge transfer resistance values and double layer capacitance values of the positive electrode were higher than those of the negative electrode. The gel resistance values increased with decreasing in SoC. This indicates that the gel resistance is an important parameter for predicting SoC of VRLA battery.