开孔屏蔽腔内传输线负载所受电磁干扰的解析算法

摘要

外界电磁场通过孔缝耦合进入屏蔽腔，并经由线缆对腔内电子设备造成干扰，这是电磁兼容中需要考虑的重要问题，而数值法分析此类尺寸跨度大的电磁问题效率过低。基于电磁拓扑和等效电路法，提出一种快速计算外界平面波辐照下开孔屏蔽腔内传输线负载所受电磁干扰的解析算法。首先利用电磁拓扑将整个耦合问题分解为两个独立的子问题：外界平面波辐照下开孔空腔内的耦合场问题与耦合场辐照下孤立传输线的响应问题，然后提出基于等效电路法求解空腔内耦合电场的计算方法，最后利用场线耦合 BLT 方程求解耦合电场对孤立传输线负载造成的电磁干扰。经 CST 仿真验证，该解析算法能有效计算任意位置开（多）孔屏蔽腔内任意放置传输线负载所受的电磁干扰。相比于数值法，该解析算法不仅花费更少的计算时间与资源，且能用于参数影响规律的研究。%Based on electromagnetic topology and equivalent circuit method,this paper presents an analytic method for the fast prediction of the load response of the transmission line in an enclosure with apertures,irradiated by an external plane wave.In the method,the whole electromagnetic coupling problem is firstly decomposed into two relatively simple sub problems:a)the ex-ternal plane wave irradiates an empty enclosure with apertures and generates interior coupling EM field,and b)the coupling field irradiates the isolated transmission line and generates the load response.Then,the coupling field is computed by equivalent circuit method,and the load response of the transmission line is computed by BLT equation.The validity of the analytic method is veri-fied by CST simulation tool.The results show that the analytic method can calculate the load response of the transmission line fast and efficiently,and costs much fewer computing resources compared with numerical methods.In addition,the analytic method offers designers feasibility to study influence parameters on the load response of the transmission line,while it is difficult with nu-merical methods.