고고도 전자기 펄스 환경에서의 전도성 및 복사성 결합 해석

Abstract

본 논문에서는 HEMP와 같은 외부전자파 환경에 노출된 전송선로 및 건물에 유기되는 전자파 결합 응답을 해석하기 위해서 정확하고 효율적인 해석 방법을 제안하였으며, 각각의 해석 방법을 전도성 결합 및 복사성 결합으로 구분하였다. 먼저 HEMP 환경에 노출된 전송선로에 대한 전도성 결합 응답을 해석하기 위해 다중도체 chain 행렬 모델을 제안하였다. 제안된 다중연결 chain 행렬 모델은 전체 선로를 단위길이 전송선로의 다중연결로 구성하여 각각의 단위길이 전송선로를 단위길이 chain 행렬로 모델링하는 것으로 BLT 방정식과 같은 기존의 전도성 결합 해석 방법과 달리 전송선로 구조에 상관없이 간단하게 적용할 수 있다. 하지만 제안된 다중연결 chain 행렬 모델을 이용하여 TWP 전송선로 구조에 대한 전도성 결합 해석을 수행할 경우, 구조적으로 bifilar-helix 형태로 구성되는 선로를 정확하게 모델링할 수 없다. 따라서 이를 보완하기 위해서 개선된 다중연결 chain 행렬 모델을 새롭게 제안하였으며, 이를 이용한 해석 결과를 기존에 제안한 다중연결 chain 행렬 모델과 상용툴을 이용한 해석 결과와 비교하여 제안된 해석 방법의 효율성과 정확도를 확인하였다. 그 다음으로 외부전자파 환경에 노출된 건물에 대한 복사성 결합의 유기 응답을 정확하게 해석하기 위해서 QCRF 분산모델을 적용한 분산 FDTD 알고리즘을 이용하는 방법을 제안하였다. 복사성 결합 해석에 이용된 QCRF 분산 FDTD 알고리즘은 다양한 물질의 전자파 해석에 적합한 FDTD 수치해석 기법을 기반으로 하고 있으며, FDTD 수치해석 기법에 해석의 정확도를 높이기 위해 건물을 구성하는 물질의 전기적 특성을 정확하게 모델링할 수 있는 QCRF 분산모델을 적용하였다. 본 논문에서는 QCRF 분산 모델 기반의 분산 FDTD 해석 알고리즘을 이용하여 2차원 건물 구조에 대한 복사성 결합 해석을 수행하여 제안된 복사성 결합 해석 방법의 정확도와 효율성을 확인하였다. 또한, 50MHz~1GHz 대역에서 다양한 건물 구조의 차폐특성을 심도 있게 분석하였다.|In this dissertation, an accurate and efficient method for analyzing the electromagnetic pulse (EMP) coupling effect on a transmission line (TL) and building under external EMP environment, such as high-altitude electromagnetic pulse (HEMP), is proposed. Each analysis method is classified by the conducted coupling and the radiated coupling. First, in order to analyze the conducted coupling for the TLs under HEMP environment, a multi-cascaded chain matrix model is proposed. The proposed multi-cascaded chain matrix model is modelled by each unit-length TL and then a chain matrix is employed to correctly connect each unit-length TL. Differently from the conventional BLT equations, this method can be applied to various uniform or nonuniform TLs. When, however, the multi-cascaded chain matrix model is applied for the conductive coupling analysis of a twisted-wire pair (TWP) TL, its accuracy deteriorates due to the bifilar-helix structure of the TWP-TL. Therefore, in order to tackle this problem, a improved version of the multi-cascaded chain matrix model is proposed by considering the bifilar-helix configuration. The efficiency and accuracy of the proposed method was validated by comparing the proposed multi-cascaded chain matrix model with commercial electromagnetic tools. Next, to efficiently analyze the radiated coupling effect on a building under external EMP environment, dispersive finite-difference time-domain (FDTD) algorithm was employed based on a quadratic complex rational function (QCRF) model. In this work, the QCRF dispersion model is applied to accurately characterize the electrical properties of windows and concretes composed of a building and then the QCRF-based FDTD algorithm is used to analyze the radiated coupling effect on two-dimensional building structures. Numerical examples are used to illustrate the efficiency and accuracy of the proposed method. In specific, the shielding effectiveness of various building structures in the frequency range of 50 MHz to 1 GHz is investigated.; In this dissertation, an accurate and efficient method for analyzing the electromagnetic pulse (EMP) coupling effect on a transmission line (TL) and building under external EMP environment, such as high-altitude electromagnetic pulse (HEMP), is proposed. Each analysis method is classified by the conducted coupling and the radiated coupling. First, in order to analyze the conducted coupling for the TLs under HEMP environment, a multi-cascaded chain matrix model is proposed. The proposed multi-cascaded chain matrix model is modelled by each unit-length TL and then a chain matrix is employed to correctly connect each unit-length TL. Differently from the conventional BLT equations, this method can be applied to various uniform or nonuniform TLs. When, however, the multi-cascaded chain matrix model is applied for the conductive coupling analysis of a twisted-wire pair (TWP) TL, its accuracy deteriorates due to the bifilar-helix structure of the TWP-TL. Therefore, in order to tackle this problem, a improved version of the multi-cascaded chain matrix model is proposed by considering the bifilar-helix configuration. The efficiency and accuracy of the proposed method was validated by comparing the proposed multi-cascaded chain matrix model with commercial electromagnetic tools. Next, to efficiently analyze the radiated coupling effect on a building under external EMP environment, dispersive finite-difference time-domain (FDTD) algorithm was employed based on a quadratic complex rational function (QCRF) model. In this work, the QCRF dispersion model is applied to accurately characterize the electrical properties of windows and concretes composed of a building and then the QCRF-based FDTD algorithm is used to analyze the radiated coupling effect on two-dimensional building structures. Numerical examples are used to illustrate the efficiency and accuracy of the proposed method. In specific, the shielding effectiveness of various building structures in the frequency range of 50 MHz to 1 GHz is investigated.