• Title/Summary/Keyword: Electromagnetic Pulse Measurement

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3.5 mm Coaxial One Port Vector Network Analysis Using Time Domain Reflectometry (반사 펄스의 주파수 해석을 이용한 광대역 3.5 mm 동축형 단일 포트 벡터 회로망 분석법)

  • Lee, Dong-Joon;Kwon, Jae-Yong;So, Joon-Ho;Kang, No-Weon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.23 no.8
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    • pp.967-975
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    • 2012
  • This paper presents a method to measure reflection coefficients of microwave devices or antennas based on time domain analysis with sampling oscilloscopes. The reflection coefficients were extracted by the Fourier transformation of echo pulses from devices with respect to the 20 GHz incident pulse signals. The three-error terms, which are commonly used for the correction of a microwave network, were determined using a 3.5 mm calibration kit. In addition, a modified error-correction model associated with a directional coupler for reflection coefficient measurements is introduced. The results were compared with those of measured with a commercial vector network analyzer.

Measurement of the Propagation Constant of a Power Cable Using a Two-Port Time-Domain Reflectometry Technique (Two-Port Time Domain Reflectometry 방법을 이용한 XLPE 전력용 케이블의 전파 특성 측정)

  • Shin, Dong Sik;Cho, Hyeon Dong;Park, Wee Sang;Yi, Sang-Hwa;Sun, Jong-Ho
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.24 no.3
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    • pp.310-315
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    • 2013
  • This paper presents a two-port time-domain reflectometry(TDR) measurement technique for extracting the complex propagation constant of a cross-linked polyethylene(XLPE) cable. For the extraction, a short pulse transmitted through the cable is measured in the time domain and analyzed in the frequency domain. The propagation constant of a 22.9 kV XLPE cable with a conductor area of 325 $mm^2$ is extracted up to a frequency of approximately 2.14 GHz. The $S_{21}$ measured using a network analyzer and the two-port TDR technique are compared for verification. As a result compared with previous TDR method, the upper possible frequency limit for extracting the propagation constant increases and the measurement error decreases.

Thermal Conductivity and Dielectric Strength Measurement of the Impregnating Materials for the Next Generation Winding Type Superconducting Fault Current Limiter (차세대권선형한류기를 위한 함침용 재료의 열전도도 및 절연 내력 측정)

  • Yang Seong Eun;Bae Duck Kweon;Ahn Min Cheol;Kang Hyoung Ku;Seok Bok Yeol;Chang Ho Myung;Kim Sang Hyun;Ko Tae Kuk
    • Progress in Superconductivity and Cryogenics
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    • v.7 no.1
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    • pp.42-46
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    • 2005
  • The resistive type high temperature superconducting fault current limiter (HTSFCL) limits the fault current using the resistance generated by fault current. The generated resistance by fault current makes large pulse power which makes the operation of HTSFCL unstable. So, the cryogenic cooling system of the resistive type HTSFCL must diffuse and eliminate the pulse energy very quickly. Although the best way is to make wide direct contact area between HTS winding and coolant as much as possible, HTS winding also needs the impregnation layer which fixes and protects it from electromagnetic force. This paper deals with the thermal conductivity and dielectric strength of some epoxy compounds for the impregnation of high temperature superconducting (HTS) winding in liquid nitrogen. The measured data can be used in the optimal design of impregnation for HTS winding. Aluminar filling increased the thermal conductivity of epoxy compounds. Hardener also affected the thermal and electric characteristic of epoxy compounds.

A CMOS UWB RFIC Based Radar System for High Speed Target Detection (초고속 이동체 탐지에 적합한 초광대역 CMOS RFIC 기반 레이다 시스템)

  • Kim, Sang Gyun;Eo, Yun Seong;Park, Hyung Chul
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.28 no.5
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    • pp.419-425
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    • 2017
  • This paper presents CMOS UWB RFIC based radar system for high speed target detection. The system can achieve resolution of 15 cm and detection range of 15 m. For developed system, single chip CMOS UWB IC is implemented. To reduce the measuring and processing time, envelope detection and equivalent time sampling technique are used. Measurement results show that the bandwidth and center frequency of UWB pulse can be adjusted in the range of 0.5 GHz~1.0 GHz, 3.5 GHz~4.5 GHz, respectively. Signal processing time including scan time over 15 m distance is about $150{\mu}sec$.

S-Band Internally-Matched High Efficiency and High Power Amplifier Using GaN HEMT Die (GaN HEMT Die를 이용한 S-대역 내부 정합형 고효율 고출력 증폭기)

  • Kim, Sang-Hoon;Choi, Jin-Joo;Choi, Gil-Wong;Kim, Hyoung-Joo
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.26 no.6
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    • pp.540-545
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    • 2015
  • This paper presents the design, fabrication and measurement results of a S-band internally-matched power amplifier using Gallium Nitride High Electron Mobility Transistor(GaN HEMT) die. In order to fabricate the S-band internally-matched power amplifier, a high dielectric substrate and alumina were used for input/output matching circuits. The measured output power is 55.4 dBm, the drain efficiency is 78 % and the power gain is 11 dB under pulse operation at the frequency of 3 GHz.

테라헤르츠 펄스 기술

  • Han, Hae-Ok;Yu, Nan-Lee;Jeon, Tae-In;Jin, Yun-Sik;Park, Ik-Mo;Kim, Jeong-Hoe;Mun, Gi-Won;Han, Yeon-Ho;Jeong, Eun-A;Gang, Cheol;Lee, Yeong-Rak;Go, Do-Gyeong;Lee, Ui-Su;Ji, Young-Bin;Kim, Geun-Ju;Han, Gyeong-Ho
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.19 no.5
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    • pp.87-103
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    • 2008
  • In recent years, the field of THz photonics based on THz pulse technology has gained tremendous, world-wide interest as a new exciting research subject. With a possibility of many commercial applications as well as fundamental scientific achievements in the field, many advanced nations are stepping up their effort in advancing the field of THz photonics. This fact is supported by the observation of the significant increase in the number of papers on THz pulse technology presented in renowned international journals and conferences. The subject that is interesting for the THz application is the development of THz pulse sources and detectors, and other passive devices. In this paper, we present a brief review on some of the key devices and their relavant measurement techniques such as THz photoconductive antennas, optical rectification, difference frequency geneneration with quasi-phase matching structures, electro-optic sampling, high speed real time measurements, THz transmission lines, and other various waveguide structures.

A Study on the Biotelemetry using Infra-red Light (적외선을 이용한 생체신호의 원격측정에 관한 연구)

  • Huh, Soo-Jin
    • Journal of Biomedical Engineering Research
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    • v.14 no.2
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    • pp.169-175
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    • 1993
  • Recently, interest in infra-red(IR) telemetry has increased because of the entirely different propagation and reflection properties of IR light as compared to radiowaves. IR hardly penetrates most materials and is reflected from obstacles. An biotelemetry system using these characteristics of indirect transmitted IR lights was developed, in which 3 ECG's are multiplexed and modulated in PDM/PIM pulse sequence. This proto-type system enables us to realize the non-restraint measurement of biological signals. Compared with conventional radio telemetry, this technique has some merits such as no electromagnetic interference, no frequency allocation problem, no government control over transmission power.

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An Experimental Study on the Measurement of Electrical Conductivity of Cementitious Composites According to the Type of Steel Fiber (강섬유 종류에 따른 시멘트 복합체의 전기전도도 측정에 대한 실험적 연구)

  • Lee, Yae-Chan;Kim, Gyu-Yong;Nam, Jeong-Soo;Lee, Sang-Kyu;Shu, Dong-Kyun;Eu, Ha-Min
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2020.06a
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    • pp.191-192
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    • 2020
  • The purpose of this study is to measure the electrical conductivity of cementitious composites as an early step to obtain shielding performance by mixing various type of steel fiber into cementitious composites, the main building material of protection facility, to shield electromagnetic pulse (EMP) damage. Fiber such as conductors as amorphous metallic fiber, hooked steel fiber, and smooth steel fiber are mixed into cementitious composites to give electrical conductivity and measure the impedance of concrete using LCR meter. By doing this, the electrical conductivity of each type of steel fiber reinforced cementitious composites (FRCC) is compared.

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Measurement and Analysis of Antenna Induced Voltage for Tactical Mobile Wireless Communication System under HEMP Environment (HEMP 상황 하 전술기동무선통신체계 안테나 유도전압 측정 및 분석)

  • Park, Kyoung-Je;Jeong, Kil-Soo;Kim, Jung-Sup;Park, Yong-Woo;Park, Jae-Hyun
    • Journal of the Korea Society for Simulation
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    • v.30 no.2
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    • pp.33-40
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    • 2021
  • The situation of high-altitude electromagnetic pulses (HEMP) arises from high-altitude nuclear explosions. The HEMP situation can be simulated through the threat level investigation (TLI). In this paper, the induced voltage according to the antenna type of the tactical mobile radio communication system was measured and analyzed by TLI. Under the influence of HEMP, electronic equipment can be paralyzed or damaged. HEMP protection filters are commercially available for power lines and signal lines. However, commercialization of HEMP filters for antennas is insufficient, and even some of them exist for lightning protection. In order to make an appropriate HEMP protection filter according to the frequency and type of the antenna, the induced voltage was measured and the maximum induced voltage was analyzed through extrapolation. It was found that the measured induced voltage decreased as the frequency increased, such as in the HF, VHF and UHF bands of the measurement results.

Multi-purpose Geophysical Measurements System Using PXI (PXI를 이용한 다목적 물리탐사 측정 시스템)

  • Choi Seong-Jun;Kim Jung-Ho;Sung Nak-Hun;Jeong Ji-Min
    • Geophysics and Geophysical Exploration
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    • v.8 no.3
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    • pp.224-231
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    • 2005
  • In geophysical field surveys, commercial equipments often fail to resolve the subsurface target or even sometimes fail to be applied because they do not fit to the various field situations or the physical properties of the medium or target. We developed a geophysical measurement system, which can be easily adapted for the various field situations and targets. The system based on PXI with A/D converter and some stand alone equipment such as Network Analyzer was applied to borehole radar survey, borehole sonic measurement and electromagnetic noise measurement. The system for borehole radar survey consists of PXI, Network Analyzer, dipole antennas, GPIB interface is used for PXI to control Network Analyzer. The system for borehole sonic measurement consists of PXI, 24 Bit A/D converter, high voltage pulse generator, transmitting and receiving piezoelectric sensors. The electromagnetic noise measurement system consists of PXI, 24 Bit A/D converter, 2 horizontal component electric field sensors and 2 horizontal and 1 vertical component magnetic filed sensors. The borehole radar system has been successfully applied to detect the width of the artificial tunnel through which the borehole pass and to image buried steel pipe, while the commercial borehole radar equipment failed. The borehole sonic system was tested to detect the width of artificial tunnel and showed a reasonable result. The characteristic of electromagnetic noise was grasped at an urban area with the data from the electromagnetic noise measurement system. The system is also applied to characterize the signal distortion by induction between the electric cables in resistivity survey. The system can be applied various geophysical problems with a simple modification of the system and sensors.