中文摘要：

本文比较了TLM、ILCM和M-MOM三种快速算法在斜入射波和多面开孔情况下计算金属腔屏蔽系数（SE）的适用性,发现M-MOM在各种情况下的计算结果最为准确,ILCM无法计算多面开缝情况,而TLM不适用于电大尺寸情况.本文还研究了电磁波的入射角和极化角、孔缝长边、腔体内观测点位置及相对面孔缝位置等参数对SE的影响.结果表明单面开缝时SE随方位角、极化角增大而增大,随仰角增大而减小,而相邻面开缝的SE则由方位角和腔体尺寸决定.当孔缝长度接近或大于半波长时,SE不再随长度的增大而减小.腔体内观测点位置不同,SE有不同的变化特性,因此仅用腔体中心点位置上的SE表示腔体的屏蔽效能是不够的.当屏蔽腔不可避免需要开缝时,应尽量选择开等效面积较小的孔缝.

英文摘要：

A comparative study of transmission line model,intermediate level circuit model and modal based method of moments for fast calculation of shielding effectiveness of a metal enclosure with apertures in multi sides and oblique incidence is conducted in this paper.Results show that the M-MOM can provide the accurate SE for almost all cases and ILCM cannot deal with multi apertures,while TLM is not applicable for electrically large structures.Moreover,the effects of incidence and polarization angles,lengths of apertures,observation positions and apertures perforated opposing walls on SE are studied.Results show that SE for apertures on the single wall increases with elevation and polarization angles,but decreases with elevation angles.However the relations between SE for apertures perforated on adjacent walls and elevation angles are relative to the structure of enclosures.When the length of apertures is equal or longer than half wavelength,SE does not decease with length increasing any more.SE varies greatly in terms of observation positions inside the cavity,so it is not reasonable using the SE at central point to represent the shielding effectiveness of the enclosure.Finally,the panel irradiated by incident wave should be perforated with small equivalent area.