核电磁脉冲与开孔金属腔体耦合特性研究

利用基于时域有限差分法(FDTD)的电磁仿真软件XFDTD,研究了核电磁脉冲与开孔腔体的耦合规律。分析了不同极化方向的核电磁脉冲入射时,矩形孔洞长宽比对耦合特性的影响;讨论了核电磁脉冲照射下,腔体谐振和孔缝与腔体的耦合谐振现象;给出了腔体内部电场分布的截面图,讨论了核电磁脉冲入射时腔体内外电场的空间分布情况。研究结果表明:当核电磁脉冲的极化方向与开孔矩形短边平行时,耦合的电场强度比正方形开孔时的要大,且长宽比越大,耦合的电场强度越大;当核电磁脉冲的极化方向与开孔矩形长边平行时,耦合的电场强度比正方形开孔时的小,且长宽比越大,耦合的电场强度越小。极化方向与矩形开孔短边平行时,腔体内产生了腔体谐振和孔缝与腔体的耦合谐振,开孔尺寸的变化会引起谐振频率的偏移;极化方向平行于长边时无明显电磁谐振发生。核电磁脉冲对屏蔽体内的影响主要局限于开孔附近。

Research on the Characteristics of the NEMP Coupling into a Metallic Cavity with Apertures

The coupling law of the nuclear electromagnetic pulse(NEMP) with the opening cavity is studied by using electromagnetic simulation software XFDTD which is based on finite difference time domain (FDTD). When the nuclear electromagnetic pulse incidents in different polarization directions, the coupling characteristic which is influenced by the aspectratio of rectangular hole is studied. This paper also discussed the phenomenon of cavity resonance and aperture cavity coupling resonance under the radiation of NEMP, and the sectional view of the electric-field distribution inside the cavity is given. The research shows that: when the polarization direction of nuclear electromagnetic pulse is parallel to the short sides of the rectangular hole, the coupling field strength is bigger than the situation of the square hole, and the larger the lengthwidth ratio, the greater the electric field strength. When the polarization direction of nuclear electromagnetic pulse is parallel to the long sides of the rectangular hole, the coupling field strength is smaller than the situation of the square hole, and the larger the length width ratio, the weaker the electric field strength. Cavity resonance and aperture cavity coupling resonance are generated in the cavity when the polarization direction of nuclear electromagnetic pulse is parallel to the short sides of the rectangular hole, and the change of the size of the hole will cause the shift of the resonant frequency; when the polarization direction is parallel to the long sides, no obvious electromagnetic resonance occurs. The effects of nuclear electromagnetic pulse on the shielding body are mainly confined to the neighboring of the open hole.