• Title/Summary/Keyword: impedance characteristics

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Extraction and Analysis of Dual Gate FET Noise Parameter for High Frequency Modeling (고주파모델링을 위한 이중게이트 FET의 열잡음 파라미터 추출과 분석)

  • Kim, Gue-Chol
    • The Journal of the Korea institute of electronic communication sciences
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    • v.8 no.11
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    • pp.1633-1640
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    • 2013
  • In this paper, noise parameters for high frequency modeling of dual-gate FET are extracted and analyzed. To extract thermal noise parameter of dual gate, noise characteristics are measured by changing input impedance of noise source using Tuner, and the influence of pad parasitic elements are subtracted using open and short dummy structure. Measured results indicated that the dual-gate FET is improved the noise figure by 0.2dB compared with conventional cascode structure FET at 5GHz, and it confirmed that the noise figure has dropped due to reduction of capacitances between the drain and source, gate and drain by simulation and analysis of small-signal parameters.

A Novel Fault Location Scheme on Korean Electric Railway System Using the 9-Conductor Representation

  • Lee, Chang-Mu;Lee, Han-Sang;Yoon, Dong-Hee;Lee, Han-Min;Song, Ji-Young;Jang, Gil-Soo;Han, Byung-Moon
    • Journal of Electrical Engineering and Technology
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    • v.5 no.2
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    • pp.220-227
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    • 2010
  • This paper presents a novel fault location scheme on Korean AC electric railway systems. On AC railway system, because of long distance, 40[km] or above, between two railway substations, a fault location technique is very important. Since the fault current flows through the catenary system, it must be modeled exactly to analyze the fault current magnitude and fault location. In this paper, suggesting the novel scheme of fault location, a 9-conductor modeling technique including boost wires and impedance bonds is introduced based on the characteristics of Korean AC electric railway. After obtaining a 9-conductor modeling, the railway system is constructed for computer simulation by using PSCAD/EMTDC. By case studies, we can verify superiority of a new fault location scheme and propose a powerful model for fault analysis on electric railway systems.

A Resonant Circuit Design of the Inverter for Induction Heating by Analysis of the Coupling Coefficient (결합계수 해석에 의한 유도가열용 인버터의 공진회로 설계법)

  • 이광직;김주홍
    • The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.11 no.6
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    • pp.90-95
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    • 1997
  • In designing a resonant circuit of the inverter which puts induction heating with high frequency to the load, an inductance L of the circuit, the coupling coefficient of a transformer transfering the output power to load, and the coupling coefficient of load circuit heating with coil affect to the output power of a resonant circuit, the circuit Q and the frequency. Those characteristics of the circuit are analyzed through Thevenan's equivalent circuit of the coupling coefficient type which is derived from the T-type equivalent circuit of a transformer. On this equivalent circuit, the impedance of a transformer referred to its primary side is not only proportional the square of turn ratio, nZ, but also the square of coupling coefficient, K2 This paper proposed a more accurate fundamental method to design a resonant circuit of the inverter by using the Thevenan's equivalent circuit.

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A Force-Reflecting Haptic interface using Ultrasonic Motors (초음파 모터를 이용한 힘 반영 촉각장치)

  • Shin, Duk;Oh, Geum-Kon;Kim, Young-Dong
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.13 no.1
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    • pp.111-118
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    • 1999
  • Throughout this thesis, I describe the design, fabrication, and evaluation of the 3 DOF farce-reflecting haptic interface using USMs(ultrasonic motors). This haptic interface allows a htmlaIl "observer" to explore and interact with a virtual environrrent for the sense of touch. To effectively display the mechanical impedance of the htmlaIl hand we need a haptic device with specific characteristics, such as low inertia, alrmst zero friction and very high stiffness. USMs have attracted considerable attention as the actuator satisfied these conditions. An observer may grasp the end effector of revice and interact with surfaces and objects created within a virtual environment The revice provires force feedback, allowing users to "feel" objects within the environment. The device works very well, as users are able to detect the edge of the wall, the stiffness of the button and the puncture. TIle force-reflecting haptic interface could be suitable as a master for micro-surgery or as an interface to virtual reality training systems.

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A Design of Insulted Diagnosis Sensor and the Characteristics of Frequency Spectrum from the Radiated Electromagnetic Waves according to Surface Discharge (GIS 절연진단센서 설계와 연면방전에 따른 방사전자파 특성)

  • Park, Sung-Gyu;Choi, Eun-Hyeok;Lee, Kwang-Sik
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.26 no.10
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    • pp.27-34
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    • 2012
  • If obstacle in GIS(Gas Insulted Switchgear), its affects are great are on the community and it is consequently demanded lots of difficulities to recover and repair. Accordingly, diagnosis techniques, that are able to prevent from accidents before they happen by providing more stable and highly reliable power effectively and finding sign of the accidents is very important. A novel UHF(Ultra High Frequency)-microstrip antenna is presented. The measured impedance bandwidth of the proposed antenna is from 0.5GHz to 15GHz with the stop band from 0.5GHz to 10.7GHz for VSWR<2. Form results of this study, The antenna is will play an important role for the senser for insulation diagnosis system by UHF method of real site GIS and power equipment using $SF_6$ gas.

A Study on Implementation and Performance of the Low Noise Amplifier for Satellite Mobile Communication System (위성통신용 광대역 저잡음증폭기의 구현 및 성능평가에 관한 연구)

  • 전중성;김동일;배정칠
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.4 no.1
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    • pp.67-76
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    • 2000
  • In this paper, a low noise amplifier has been developed, which is operating at L-band i.e., 1525-1575 MHz. By using resistive decoupling circuits, the resistor dissipates undesired signal in low frequency band. By adopting this design method the stability of the LNA is increased and the input impedance matching is improved. The LNA consists of the low noise GaAs FET ATF-10136 and the internally matched VNA-25. The low LNA is fabricated by both the RP circuit and the self-bias circuits in an aluminum housing. As a result, the characteristics of the LNA implemented show more than 32 dB in gain, lower than 0.5 dB in noise figure, 18.6 dBm output gain in 1 dB gain compression point.

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RFID Location Based Tree Management System (TMS) Using Insertion UHF RFID Tag and GPS (UHF RFID 태그와 GPS를 사용한 위치기반 수목관리용 RFID 시스템 구현)

  • Nam, Seahyeon;Chung, You Chung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37C no.10
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    • pp.909-914
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    • 2012
  • The paper introduces the RFID location based Tree Management System (TMS) using UHF RFID tag and GPS. The bolt shape tag has been developed since the wood material has high dielectric constant. Since the characteristics and impedance of tag antenna can be changed by the material next to the tag, the plastic bolt shape tag antenna has to be carefully designed with consideration of the high dielectric constant of the wood material. The RFID TMS system has been utilized with the bolt shape tag antenna and GPS. The TMS system uses and links Google map to locate the location of the trees. Therefore, this system allow us to manage the trees economically and efficiently.

The Ferroelectric Frequency characteristics of Bi$_{4-x}La_x$Ti$_3O_12$ ceramics with the variation of Lanthanum additives (La 첨가량에 따른 Bi$_{4-x}La_x$Ti$_3O_12$ 강유전체의 주파수특성)

  • 김응권;박복기;박기엽;박춘배
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11a
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    • pp.463-466
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    • 2001
  • In recent year, Ferroelectric BLT($Bi_{4-x}$La$_{x}$Ti$_3$O$_{12}$) is a promising candidate materials. This study was Practiced to make good conditions of BLT targets. In this study, calcination and sintering temperature were kept at 75$0^{\circ}C$, 110$0^{\circ}C$ for 2 hour respectively. the density obtained 7.612, 7.98, 7.877 g/㎤ as La$_2$O$_3$ contents were 0.0mol%, 0.25mo1%, 0.5mol%. Especially, the lanthanum content of 0.5 mol% measured C-axis (117) preferred orientation more than the others targets in the XRD. In $\varepsilon$$_{r}$-f relationship using by HP 4194 A impedance analyzer, the 0.5 mol% observed above 200 relative dielectric constant. but the dissipation factor was higher than others targets at 100Hz~13MHz range. SEM photograph with the content of La$_2$O$_3$ was observed like rod and plate types.types.s.

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A study on Electrical and Electromagnetic Properties for Driving the Ring-shaped electrodeless fluorescent lamp (환형 무전극 형광램프 구동을 위한 전기적, 자기적 특성 분석)

  • Jo, Ju-Ung;Lee, Young-Hwan;Nam, Joong-Hee;Choi, Yong-Sung;Kim, Yong-Kab;Park, Dae-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.05b
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    • pp.69-72
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    • 2004
  • In recent, there have been several developments in lamp technology that promise savings in electrical power consumption and improved quality of the lighting space. Above all, the advantage of ring-shaped electrodeless fluorescent lamp is the removal of internal electrodes and heating filaments that are a light-limiting factor of conventional fluorescent lamps. The ring-shaped electrodeless lamp is intended as a high efficacy replacement for the incandescent reflector lamp in many applications. Therefore, the life time of ring-shaped electrodeless fluorescent lamps is substantially higher than that of conventional fluorescent lamps and last up to 60,000 hours. In this paper, we present measurement results of electrical characteristics of a ring-shaped electrodeless fluorescent lamp as a function of frequency and number of coil turns using a highly permeable Mn-Zn ferrite. It is found that the impedance are increased while the quality factor decreases as frequency increases.

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A Study on Gel-free Probe for Detecting EEG (뇌파 탐지용 Gel-free probe 연구)

  • Yun, Dae-Jhoong;Eum, Nyeon-Sik;Jeong, Myung-Yung
    • Journal of Sensor Science and Technology
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    • v.21 no.2
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    • pp.156-166
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    • 2012
  • Over the past 15 years productive BCI research programs have arisen. Current mainstream EEG electrode setups permit efficient recordings but most of electrodes has the disadventages of need for skin preparation and gel application to correctly record signals. The new gel-free probe was adapted for EEG recording and it can be fixed to the scalp with the micro needle without neuro-gel. It use standard EEG cap for wearing electrodes on scalp so it is compatible with standard EEG electrodes. A comparison between electrode characteristics is achieved by performing simultaneous recordings with the gel electrodes and gel-free probe placed in parallel scalp positions on the same anatomical regions. The quality of EEG recordings for all two types of experimental conditions is similar for gel-electrodes and gel-free probe. Subjects also reported not having special tactile sensations associated with wearing of gel-free probes. According to our results, it is expected that gel-free probe can be adapted to BCI, BMI(Brain Machine Interface), HMI(Human Machine Interface) because of its simple application and comfortable wearing process.