• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.1
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• pp.23-28
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• 1999

Rectangular waveguide slot antenna which has simple structure, high efficiency, high trust and small size, is extending in a field of application such as many Radar and Microwave communication. A slot cut into a wall of waveguide is propagated electromagnetic wave to free space it interrtupts the flow of current inner conductor of waveguide. Therefore incident of slot, cutdepth, width, length, i.e. are important parameter of characteristic change of the slot antenna. Result from difficulty of theoretical analysis about slot frequently experimental measured data useful design and manufacture have been accomplished. In this paper, we find the suitable method of analysis that compare two analysis results with measured result of established literature - admittance of slot be solved by propagated power from electric field distribution of slot and mode current computation and accomplishment of computable chart which hasresonant length and cutdepth, incident of slot, i.e. and use the HFSS which applyed finite-element method obtain equal slot analyed method.

• Geophysics and Geophysical Exploration
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• v.2 no.2
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• pp.96-103
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• 1999

Most of saline water inousions have been diagnosed by geophysical or geochemical approach independently. The objective of this study is to provide the effective method to detect the saline water intrusion on the ground water in the vicinity of seashore using these two methods. Schulumberger sounding, frequency domain electromagnetic sounding and geochemical analysis of ground water were carried out to explore saline water intrusion. Schulumberger sounding was implemented in dry surface condition before irrigation water was introduced into the field, while electromagnetic sounding was carried out in wet ground condition after the irrigation. The purpose of duplicated measurements on the equivalent spot at different times was to investigate the variation of anomaly zone depending on the amount of ground water. It was possible to discriminate the anomalous zone due to high water saturation from the low electric resistivity zone by high salt concentrations through this way. For the verification of the geophysical result, the ground water samples in the study area were collected and analysed at the 23 points near the measuring spots. The groundwater at the spot nearest to the sea water intrusion identified by geophysical method indicates higher salinity than the standard limit concentration for agricultural irrigation water (250 mg/1). Isotope analysis of $D({^2}H)$ vs. is ${^18}O$ and PCA analysis were used to discriminate the anthropogenic pollution from those of high salinity from sea water intrusion.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.10
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• pp.1204-1211
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• 2012

Measurement and analysis results of the extracted radiation-patterns from the field-experiments which were conducted to acquire the generic technology for calibration and validation of the satellite SAR system(Synthetic Aperture Radar) are presented in this study. Prototype of active transponder is adjustable within maximum 63.1 dBsm of RCS (Radar Cross Section) and includes the receiving-function with external receiver. To increase an accuracy of these field experiments, we repetitively measured satellite SAR systems of the same operating mode(i.e., COSMO-SkyMed No. 2 & 3, hh-pol., strip-map himage mode, 3 m resolution). Then, the reliability of experimental results was cross-checked through analysis of the RCS of active transponder on SAR image. The property of azimuth radiation patterns of satellite SAR system extracted from them has $0.352^{\circ}$ of HPBW(half-power beamwidth), $0.691^{\circ}$ of FNBW(first-null beamwidth), and 11.17 dB of PSLR(peak to side lobe ratio), respectively.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.3
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• pp.229-232
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• 2005

Finite element method (FEM) is a very powerful tool for the calculation of magnetic field of electromagnetic devices. MATLAB/Simulink is also well known as a very useful tool for control systems. This paper proposes a very promising method, where the FEM is coupled with MATLAB. We apply this method to analyze a permanent magnet (PM) motor drive system, and compare with results using MATLAB only.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1772-1774
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• 2004

Because the physics occurring during an interruption process is not well known, it is not easy to analyze the characteristics of a self-blast circuit breaker neither theoretically nor experimentally. Fortunately the available computational power and the numerical method improved recently make it possible to predict an interruption process as precisely and fast as possible. Therefore many researches using computational methods have been done for the interruption process of interrupters and applied to extend the information such as thermal and dielectric reignition. In this paper, we have simulated the interruption process of SF6 self-blast circuit breakers with the arc plasma during the fault interruption of a 10 kA current. The CFD program used here is coupled with the electromagnetic field analysis, the radiation model and the effects of turbulence. Through this work, we have get further information about the thermal performance as well as the behavior of the arc. The results have been compared with the measured arc voltage.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.113-115
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• 2003

Recently, many linear motion generators and are rapidly finding applications that ranges from short stroke linear motion vibrators, such as dynamic cone type loud speakers tostirling engine driven linear reciprocatings, alternators, compressors, textile machines etc. In this paper the dynamic performance with load is computed by a general purpose method, which the equation of electromagnetic field, the equation of electric circuit and the equation of motion are coupled together. We fumed out the driving system and the dynamic characteristics of current, voltage and displacement is confirmed experiment.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.565-569
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• 2002

To improve the driving sensitivity of an optical pickup actuator for high density and high speed drive, we present a new actuator design using multipolar flux-density distribution by magnetic materials and Nd-Fe-B sintered magnets. We expect this actuator to use in 3-axis actuator for tilt compensation as well as conventional 2-axis actuator. The electromagnetic field analysis applying 3-D FEM was performed and several samples were actually tested. From comparing simulated data with experimental results, we verified the accuracy of the simulation and the superiority of the presented method.

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.121-122
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• 2007

본 연구는 유한 길이를 갖는 솔레노이드 내에 원통형 도체가 존재하는 경우, 코일에 펄스 전압을 인가했을 때 정적, 동적 특성을 고찰하였다. 또한 솔레노이드 내에 자속을 한 부분으로 집중시켜주는 B-field shaper를 삽입하여 같은 방법으로 펄스 전류 인가시의 정적, 동적 특성을 고찰하였다. 원통형 도체의 재질로는 Al, Cu, Fe 계열을 사용하였으며, 인가 전압은 고압용 콘덴서를 충전하여 수백 micro sec 단위의 짧은 시간에 통전하였다. 본 논문에서는 유한 길이 솔레노이드는 설계 기본 방법을 제시하였고, 설계된 시작품에 대한 동적특성 해석은 유한요소법을 이용하여 검증하였다. 해석결과로는 현상에 따른 솔레노이드 내의 원통 도체에 작용하는 자기력 분포, 인덕턴스 등 설계 변수에 대한 자기력 특성 값을 제시하였다.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.381-383
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• 2006

A de-wiring trolley wire usually makes the electrical system complex and may have an adverse effect on the electrical system inside the train. It is important to analyze the effect on trains in de-wiring trolley wire. we accomplished an equivalent model of the electric train system. We used PSCAD/EMTDC, an electromagnetic transient program. The result of this study can be used as a facility design to use a power conversion system filter and needs to prove through actual field data in the main circuit of an electric train for a precise analysis about effect of de-wiring.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 1999.02a
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• pp.146-149
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• 1999

A 30kVA superconducting generator has been designed, developed and successfully tested recently. The design is based on 2-dimensional electromagnetic field analysis. The rotor has been wound with superconducting wire of Nb-Ti alloy. The stator has the air-gap type armature windings. Open-circuit test, short-circuit test and lamp load test have been conducted. The details of design program, design, machinebuilding, test results and conclusions are given in this paper.