利用扩展TLM研究内置带孔隔板结构的箱体屏蔽效能

Analyzing of Shielding Effectiveness of Enclosure with Inner Plate with Round Hole Based on TLM

基于扩展的传输线方法,对内置带孔金属隔板的带缝箱体,建立了平面波照射下腔体屏蔽效能的等效电路模型,推导出屏蔽效能的计算公式,屏蔽效能的计算结果与CST软件仿真结果进行对比,验证了扩展的传输线方法计算的可行性.分析了金属隔板上圆孔的尺寸及位置对电场屏蔽效能的影响,以及金属隔板的位置对测试点的屏蔽效能的影响,结果表明圆孔直径越小,位置离开隔板中心的距离越大,屏蔽效能越高,谐振频率向下偏移量越大;隔板位置的变化会造成箱体谐振频率的偏移,隔板距离孔缝面越近,谐振频率向上偏移且偏移量越大.基于单缝单孔的箱体,对含有多缝多孔的复杂箱体进行分析,结果表明增加孔和缝的数量会使屏蔽效能增大,孔数量的改变也会使谐振频率产生偏移.

Based on the adjusted transmission line method（TLM）,the shielding effectiveness of an enclosure with aperture and inner metal plate with round hole was analyzed.The equivalent circuit model was established under plane wave and the electric shielding effectiveness（SE）is calculated as a function of the opening wideness of metal windows.The result of TLM was in good agreement with the CST simulation result.The electric shielding effectiveness under different structure of inner metal plate was analyzed.The result showed that the smaller size of the round hole and larger distance between the hole and plate center will make the higher shielding effectiveness and the resonance frequency of cavity will shift down.Also different position of inner metal plate will cause the resonance frequency of the cavity shift.The smaller distance between plate and aperture face will make resonance frequency shift up more.Based on the enclosure with single aperture and round hole,the complex enclosured with multiple apertures and round holes was analyzed.The result shows the increasing number of apertures and round holes will raise the electric shielding effectiveness and also make the resonance frequency shift.