• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.7
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• pp.1378-1384
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• 2011

In this paper, the electromagnetic shielding performance of a BiMODAL Tram is investigated by means of an electromagnetic analysis tool, called HFSS. For the purposed of doing this, first, three-dimensional finite element modeling for the tram including electronic devices and engine room is carried out. Then, for quantitatively assessing the electromagnetic shielding performance of the tram's body, concentration indexes for electric field magnitude and time-average stored electric energy are introduced. From numerical results, it is inferred that the tram's body can protect the electronic devices and engine room against external electromagnetic waves from 30 MHz to 100 MHz.

• Journal of Magnetics
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• v.11 no.2
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• pp.90-94
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• 2006

A finite-element method is used to analyze loss generation and electromagnetic noise absorption characteristics of a coplanar waveguide transmission line integrated with a magnetic thin film. Parameters used in the analysis are the electrical resistivity of the magnetic layer and the thickness of both magnetic and insulating layers. The results indicate that L-C resonance is the main loss mechanism of the electromagnetic noise absorption.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.2 no.1
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• pp.37-45
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• 1991

The electromagnetic field distribution within rectangular coaxial transmission lines (RCTL:TEM cells) is calculated using a numerical method. Boundary integral equations(BIE) considering equivalence theorem and extended boundary condition(EBC) in tapered region are used, thereby restricting the operational frequencies (0~130 MHz) below the cell cutoff frequency(130 MHz). The EM fields within NIST TEM cell ($1\times0.6\times2m$) are calculated by this method. The results of the numerical calcuation have a good agreement in the cross-sectional EM field distribution of TEM cell with 2-dimensional analysis results. Based on this method, the first cutoff freque- ncy in high order modes in the cell and the electric field polarization are considered.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.6 no.2
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• pp.11-18
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• 1995

The goal of this research is to get a measuring system for absorption characteristics of electromagnetic wave absorbers in fernite type which are flat, grid-type and special type, etc. It is, however, very difficult to measure the absorption characteristics in as low frequency as 30 MHz. To solve the problem, therefore, we propose a standing wave method and a measurement method in time domain using paralledl striplines, construct the measuring system, and measure the charac- teristics of ferrite microwave absorbers in grid type using the proposed measuring system.

• Transactions of the Society of Information Storage Systems
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• v.2 no.4
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• pp.230-235
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• 2006

The machine locking system is an important device for the safety of persons using the machine. In this study, a locking system using electromagnetic fields is proposed to decrease the defects and the cost for repairing and maintenance of the existing locking system using structural mechanism. We analyze the electromagnetic locking system and calculate the generated force considering direction by the finite element method. Also, we set up two design domains for the topology optimization; first domain is optimized to reduce the volume and the other is optimized to maximize the generated force keeping the volume, especially. The optimal design is obtained by integration of the two optimized results. An improved design is obtained by the optimal topology and it is confirmed by comparison with the initial locking system.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.812-821
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• 2018

An electromagnetic excitation force is caused by the air-gap flux density, which greatly influences the noise and vibration of the motor. In many real projects, skewed slot technology is widely used to reduce the harmonic components of the air-gap flux density to reduce the noise and vibration of the motor. However, a skewed slot has several side effects such as a transverse current and axial drifting. Thus, a double skewed slot rotor is selected with the aim of eliminating these side effects. This paper presents the exact structure of the double skewed slot rotor and the mechanism whereby the electromagnetic excitation force can be reduced. A multi-slice method is adopted to model the special structure. Finite element simulation is used to verify the theory.

• Transactions of the Society of Information Storage Systems
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• v.7 no.2
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• pp.80-84
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• 2011

In this paper, we propose the integrated design method that enables multi-physics modeling and coupled-field analysis by connecting an electromagnetic field and a structural field. We design the 3-axis moving magnet type actuator that has the high structural stiffness and the effective electromagnetic circuit generating large electromagnetic force. Through design of experiments (DOE) and optimization, the designed actuator is optimized and satisfies high dynamic characteristics over the desired specifications.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.4
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• pp.483-490
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• 1998

The reflectivity of a grid ferrite electromagnetic wave absorber is analyzed using finite difference time domain (FDTD) method, which is usually used in anechoic chambers for EMI / EMS test. The frequency dispersive characteristics of ferrite medium and its boundary condition are modeled using magnetic flux in addition to E- and H-fields. By applying Floquets theorem, FDTD analysis of the grid ferrite absorber with periodic infinite array is simplified as a unit cell problem. The method of homogenization which is mainly utilized in the calculation of absorber reflectivity as a low frequency technique takes only into account volume fraction of the unit cell of the absorber except for the structure of medium geometry. However, the presented method in this paper can analyze the geometry effect of the unit cell with its medium characteristics up to high frequency region.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.11
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• pp.1023-1026
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• 2016

We calculate the propagation characteristic of antennas considering refractive indices of space environments. The effective indices of troposphere, stratosphere, and inonshpere are computed and the ray tracing method, geometrical optics, and Huygens' principle are used to estimate refracted and attenuated electromagnetic wave of space environment.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.80-82
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• 1995

The electromagnetic force of magnetic plunger for electromagnetic pump system are calculated by finite element method which consider the eddy current, the plunger motion. The mechanical motion equation are solved Rune-Kutta method, and coupled with the finite element method. With the external circuit equation dynamic simulation of the pump system are achieved. Electrostatic flux is verified by comparing with other commercial analysis software. Similar analysis of other type solenoidal actuators can be done by this procedure.