• 한국전자파학회논문지
• /
• 제14권5호
• /
• pp.431-436
• /
• 2003

본 논문에서는 전자파 장해 및 복사내성 측정에 사용되는 준전자파 무반사실의 대용 방법으로 활용될 수 있는 전자파 잔향실 중에서 원통형 구조 전자파 잔향실의 전자기장 특성과 모드 분포를 연구하여 원통형 구조 전자파 잔향실의 모드 수 계산법을 제시하였으며, 이것을 사용하여 체적이 동일한 원통형 전자파 잔향실의 모드수를 반지름과 높이 비에 따라 비교 분석하였다. 또한 각각의 체적이 동일한 직사각형, 직각 이등변 삼각형, 원통형의 전자파 잔향실의 필드 균일도를 FDTD(Finite-Difference Time-Domain)를 이용하여 비교 해석하였다.

• Journal of Electrical Engineering and Technology
• /
• 제8권2호
• /
• pp.364-370
• /
• 2013

In the current paper, we propose a new modeling algorithm to analyze the coupling between an incident electromagnetic field (EMF) and a twisted conducting line, which is a kind of non-uniform line. Typically, analysis of external field coupling to a uniform transmission line (TL) is implemented by the Baum-Liu-Tesche (BLT) equation so that the induced load responses can be obtained. However, it is difficult to apply this method to the analysis of a twisted conducting line. To overcome this limitation, we used a chain matrix composed of ABCD parameters. The proposed algorithm expands the dimension of the previous chain matrix to consider the EMF coupling effectiveness of each twisted pair, which is then applied to multi-conductor transmission line (MTL) theory. In addition, we included a comparative study that involves the results of each method applied in the conventional BLT equation and new proposed algorithm in the uniform two-wire TL case to verify the proposed method.

• Journal of Magnetics
• /
• 제22권1호
• /
• pp.104-108
• /
• 2017

Induction motors have wide applicability in many fields, both in industrial sectors and households, for their advantages of a high efficiency and robust structure. The introduction of power-source-containing harmonics into the induction motor winding lowers its efficiency and increases its temperature, greatly affecting its operation characteristics. In this study, we performed an electromagnetic field analysis using the time-difference finite-element method with the purpose of analyzing the steady-state current characteristics of an induction motor. Additionally, we calculated the steady-state current with a method combining an electromagnetic field equation and a circuit equation. In the electromagnetic field analysis, the nonlinearity was taken into account using the Newton-Raphson method, and a backward time-difference method was employed for the time derivative term. Then, we compared the steady-state current of the induction motor obtained by calculation with the experimentally measured values, thus validating the proposed algorithm. Furthermore, we analyzed the impacts of the shape and material of the rotor conductor bar of the induction motor on the steady-state current of the main winding.

• 한국전자파학회:학술대회논문집
• /
• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
• /
• pp.13-17
• /
• 2003

In this paper, the design parameters for the magnetic field source at extremely low frequency are proposed. This facility can be used for in vivo experiments with small animals to investigate biological response to the driving magnetic fields. In case that the exposed animals are motionless, the animals may be affected by the directivity of driving field. To avoid this effect, a 2-axis ELF magnetic field driving apparatus was designed, The optimum location and number of turns of each coil were obtained by numerical analysis. Applying these data to the MATLAB code (for computation), the magnetic field distribution was obtained. The calculation result for a well-designed facility showed that the space in which the amplitude of the magnetic field lies within the 95% of the magnetic field distribution was more than 60% of each axis length.

• 한국전자파학회논문지
• /
• 제25권12호
• /
• pp.1201-1211
• /
• 2014

본 논문에서는 무한 도체평판의 슬롯을 통해 침투하는 침투 전자파를 저감(차단)시키기 위한 개구면 차단필터를 제안하고 슬롯으로 침투하는 전자파의 저감(차단) 특성을 검토하고 있다. 개구면 차단필터의 개념을 정립하기 위해 무한 도체평판에 있는 슬롯의 개구면 전계분포에 관한 적분방정식을 유도하고, 적분방정식의 해를 모멘트법으로 구하여 평면파가 슬롯 개구에 입사할 때 개구면 차단필터에 의한 침투 전자파의 저감(차단) 효과를 검토하였다. 이론해석의 결과, 도체평판의 슬롯으로 침투하는 침투 전자파를 저감(차단)시킬 수 있는 개구면 차단필터가 실현 가능함을 확인할 수 있었다. 개구면 차단필터의 개념 및 이론해석의 타당성을 검증하기 위해 폭이 좁은 슬롯에 개구면 차단필터를 부착하여 침투 전자파의 저감(차단) 효과를 실험적으로 확인하였다.

• 한국전자파학회논문지
• /
• 제18권5호
• /
• pp.471-477
• /
• 2007

본 논문은 전자파 장해 및 복사 내성 측정의 대용 시험 시설로서 활용될 수 있는, 다중 유전체로 구성된 평탄형 QRD(Quadratic Residue Diffuser)를 사용한 전자파 잔향실에 대한 연구이다. 잔향실은 $2.5{\sim}3$ GHz 대역에서 사용 가능하도록 설계되었으며, 기존 QRD의 특성을, 다양한 유전체를 이용하여 낮은 평탄형 구조물로 구현하였고, 이를 적용한 전자파 잔향실 내부에서의 전자기장 특성 변화 및 시험 공간 확장에 관해서 비교 분석하였다. 잔향실 내부의 전자기장 분포 해석을 위해서 FDTD(Finite-Difference Time-Domain) 수치 해석 방식을 이용하였다. 잔향실 내에 새로 제안된 확산기를 사용하면, 기존 확산기에 비해 물리적인 크기가 줄어들 뿐만 아니라 전자기장 균일도, 편파 특성 및 공차 등의 성능이 비슷하거나 우수해짐을 확인하였다. 따라서 다중 유전체로 구성된 평탄형 확산기를 사용한 잔향실이 기존의 QRD를 사용한 잔향실에 비해 전자기적 성능 및 공간 활용면에서 우수한 시험시설임을 확인하였다.

• 한국소음진동공학회논문집
• /
• 제22권8호
• /
• pp.791-799
• /
• 2012

In this paper free vibration analysis of symmetric and cross-ply elastic laminated shells based on FSDT was performed through discretization of equations of motion and boundary condition. Structural model of laminated composite cylindrical shells subjected to a combination of magnetic and thermal fields is developed via Hamilton's variational principle. These coupled equations of motion are based on the electromagnetic equations(Faraday, Ampere, Ohm, and Lorenz equations) and thermal equations which are involved in constitutive equations. Variations of dynamic characteristics of composite shells with applied magnetic field, temperature gradient, and stacking sequence are investigated and pertinent conclusions are derived.

• 한국군사과학기술학회지
• /
• 제11권6호
• /
• pp.74-80
• /
• 2008

Analysis of the electromagnetic environment on topside of a ship is needed for optimal arrangement of all kinds of antennas to be installed on the shipboard in order to minimize the probability of EMI of equipment and subsystems in real ship after construction phase. In this paper we analyze the characteristics of electric-fields such as radiation patterns and near E-fields of V/UHF antennas installed on a shipboard. We compare simulated results with measurements on the real ship for near E-fields to verify the reliability of the computed electromagnetic environment. Although there are various factors causing errors such as cable loss and impedance mismatching etc. when measuring near E-field, both data show similar trends in the range of the acceptable tolerance.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 1999년도 학술대회논문집-국제 전기방전 및 플라즈마 심포지엄 Proceedings of 1999 KIIEE Annual Conference-International Symposium of Electrical Discharge and Plasma
• /
• pp.141-144
• /
• 1999

This paper offer fundamental ones about insulation diagnosis with electromagnetic wave, when discharges occurred. To simulate Partial-Discharge(PD), It is used needle-plane electrode in air. As the voltages applied, measure the electromagnetic wave with monopole antenna and analysis its fundamental characteristics, then, acquired data were operated. The results presented as the form of graph, and the magnitude of charge when occurred PD simultaneously. In conclusion, when the magnitude of charge over 100[pC], the electric field strength changed, and then the magnitude of charge and the electric field strength increased samely.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2012년도 추계학술대회 논문집
• /
• pp.653-660
• /
• 2012

In this paper free vibration analysis of symmetric and cross-ply elastic laminated shells based on FSDT with two different boundary conditions(C-C, S-S) was performed through discretization of equations of motion and boundary condition. Model of laminated composite cylindrical shells subjected to a combination of magnetic and thermal fields is developed via Hamilton's variational principle. These coupled equations of motion are based on the electromagnetic equations (Faraday, Ampere, Ohm, and Lorenz equations) and thermal equations which are involved in constitutive equations. Variations of dynamic characteristics of composite shells with applied magnetic field, temperature gradient, and stacking sequence for each boundary conditions are investigated and pertinent conclusions are derived.