【作者】 李树军；

【导师】 马富明；

【作者基本信息】 吉林大学 ， 计算数学， 2011， 硕士

【摘要】 电磁场的时域有限差分法(FDTD)是基于在时间和空间中对Maxwell旋度方程进行差分离散化,利用具有二阶精度的差商来代替原方程的微分形式。本文利用FDTD法研究了含孔腔体的电磁屏蔽效能问题,介绍了FDTD方法的原理,讨论了数值色散关系,给出了FDTD法关于空间步长△x与时间步长△t的courant稳定条件。论文推导了Mur和PML两种吸收边界条件并给出了在吸收边界处的FDTD差分离散格式,同时以平面正弦波为激励源验证了PML吸收边界的吸收效果。在文中利用FDTD法对含孔腔体进行了数学建模,仿真分析了孔缝对腔体屏蔽效能的影响。通过与等效传输线法的对比证明了本文所建模型的正确性,在此基础上,分别就NEMP激励源与腔体对称双侧开孔情况进行了讨论分析。本文将法拉第积分环路法应用到解圆柱形含孔腔体电磁屏蔽效能问题,推导出了FDTD法的三维共形网格算法,建立了导弹侧壁开孔计算模型,且结合matlab编程技术仿真分析了导弹侧壁开孔情形下,分别开有面积形同、形状不同的孔缝对弹体内设备屏蔽效能的影响。更多还原

【Abstract】 Discreting the Maxwell curl function in time and space,finite difference of time do-main(FDTD) method makes use of difference quotients with two order accurancy to replace differential in original equations.In this paper, FDTD method was used to research shielding effectiveness for the cavity with slots. We also introduce the principle of FDTD method, discuss the numerical disper-sion relation,and show the courant stability conditions of the FDTD method on the space stepΔx and the time stepΔtIn the third chapter Mur and PML absorbing boundary conditions were derived, and FDTD discrete difference scheme in the absorbing boundary was presented.FDTD method was used to construct the mathematical model for the cavity with slots, and simulate the influence of cavity aperture on the shielding effectiveness.By comparing the TLM method, the correctness of the FDTD method was proved. According to the discussion above, the NEMP excitation source and the cavity with the hole of bilateral symmetry were discussed respectively.In the papter the Faraday loop method was applied on the electromagnetic shielding effectiveness of the cylindrical cavity with slots,and introduced the conformal mesh method of FDTD in 3D.Combined with the matlab programming.then analyzed the effect of open-ing on the missile’s side wall to the shielding effectiveness for electronic equipments in the missile’s body. Compared the effect of the shielding with different shape openings having the same area.更多还原