混合孔缝箱体屏蔽效能电磁拓扑分析方法

Electromagnetic Topology Analysis Method for Shielding Effectiveness of Enclosure with Multi-scale Apertures

武器产生的电磁脉冲会通过＂前、后门＂耦合效应对箱体内部电子元器件及电路板造成毁伤,严重威胁到电气电子设备的安全运行。为此,必须对箱体电磁屏蔽效能（SE）进行分析研究。基于Robinson等效电路模型,提出了一种估算混合孔缝箱体屏蔽效能的电磁拓扑理论（EMT）方法。以孔缝散射参数为基础,建立了箱体外部场和内部场的BLT方程,解决了孔缝耦合问题;通过引入偏心系数对孔缝等效阻抗进行修正,实现了对偏心孔缝箱体的屏蔽效能分析;基于电磁波相干原理,将混合孔缝箱体的内部场分解成偏心单孔和偏心孔阵箱体内部场,从而实现了对混合孔缝箱体的屏蔽效能分析。基于CST仿真数据,在0～1.5 GHz频域内,对Robinson、Parisa Dehkhoda和EMT算法结果进行对比分析。仿真结果表明,EMT算法的最小误差均值为3.227 2 dB,最大误差均值为5.467 5dB,其计算精度较高。EMT算法的运行时间是CST仿真软件的1/23,比Robinson、Parisa Dehkhoda算法的运行时间长,但仍保持了较高的计算效率。该算法建立了箱体、孔逢参数与屏蔽系数间的直接映射关系,比CST仿真软件更适用于工程实践。

Electromagnetic pulse from weapons could destroy the electric components and circuit boards in enclosures through the front-back door coupling effect, threatening the safe operation of electric components. Thus, it is necessary to research the electromagnetic shielding effectiveness （SE） of enclosures. Consequently, we put forward an electromagnetic topology （EMT） method for SE estimation of enclosures with multi-scale apertures based on the Robinson equivalent circuit model. A BLT equation of the enclosure＇s internal and external field was built to solve the aperture coupling prob- lem on the basis of the aperture scatting parameters. Then, we analyzed the SE of enclosures with off-center apertures through introducing the off-center parameters to revise the equivalent resistance. On the basis of the electromagnetic wave coherence principle, we decomposed the internal field of an enclosure into two internal fields, namely, the off-center sin- gle aperture and the off-center aperture arrays, and realized the SE analysis for enclosures with multi-scale apertures. Moreover, by simulations in CST, we compared the results, which were obtained using Robinson, Parisa Dehkhoda, and EMT algorithms, respectively, in a frequency domain of 0-1.5 GHz. It is concluded that, the minimum and maximum mean errors of the EMT method are 3.227 2 dB and 5.467 5 dB, respectively, showing the method is accurate. Though the running time of the EMT method is 1/23 times of CST, which is longer than that of the Robinson and Parisa Dehkhoda algorithms, the EMT method is efficient. Besides, since the EMT method establishes a direct mapping relationship be- tween the shielding coefficients and the parameters of enclosure and aperture, it is more applicable than CST in the engineering practice.