有耗介质空间完全匹配层吸收边界条件及其应用

 针对Gedney提出的完全匹配层(PML)无法用于有耗各向同性计算域的截断及其对倏逝波的衰减不理想等问题，提出了一种扩展方法。扩展的PML的主要思想是在各向异性的PML中引入与有耗介质空间相一致的复介电常数和复磁导率，使之可以与有耗介质计算域相匹配。通过给PML的张量介电常数、张量磁导率增加衰减因子以加速倏逝波的衰减。构造了PML吸收效果验证模型，数值结果证明了扩展的PML在处理有耗介质计算域截断问题中的有效性。利用该吸收边界条件，采用时域有限差分法计算了电磁脉冲作用下地面铺设电缆的电磁脉冲响应，计算结果和试验结果取得了较好的一致。

Perfectly matched layer absorbing boundary condition and itsapplication in truncation of lossy media space

Extensional method was presented for the origin of Gedney perfectly matched layer(PML) absorbing boundary condition could not be used in truncation of lossy media and was not effective in absorbing evanescent waves. The main idea of extensional PML was to overcome the limitation of Gedney PML by deriving complex permittivity and complex permeability from lossy media to PML. Evanescent coefficient was put forward also to accelerate evanescent wave fading down. The computational model was designed to study the reflection of PML to lossy media. The numerical results prove that the extensional method is very efficient in terminating computational domain composed of lossy media. The extensional PML was used in FDTD method to simulate the EMP effect of a ground laying shielded cable. Compared with experimental data, the numerical results have proved to be reliable.