贯通导体及其电路对金属腔体内部电磁场的影响

为研究贯通导体及其负载电路对金属腔体内部电磁场的影响,建立了不同贯通导体端接负载模型,使用电磁仿真软件CST进行仿真,利用GTEM室、矢量网络分析仪、功率放大器、ETS电场探头组建实验测试系统,验证了仿真结果的正确性,揭示了贯通导体及其电路对金属腔体内部电磁场的影响规律。研究结果表明:腔体内部电磁场同时受到贯通导体与腔体谐振的影响,在谐振频点干扰场强取得极大值,屏蔽效能取得极小值甚至为负值。贯通导体端接负载不接地与贯通导体两端开路情形相似,贯通导体端接负载直接接地时内部场显著降低,谐振频点降低,贯通导体端接负载浮点接地时内部场变化规律低频时与开路模型相似,高频时与直接接地模型相似。贯通导体端接负载的电阻值、电容值也会影响腔体的内部场。

Influence of electromagnetic field on metallic enclosure caused by penetrating conductor and its load circuit

In order to study effect on electromagnetic field in enclosure affected by penetrating conducting and its circuit, different models of penetrating and its circuit were established. Electromagnetic simulation software CST was used to do simulation. Experimental system was set up with a GTEM chamber, a vector network analyzer, a power amplifier and an ETS electric field probe to verify simulation results. Laws of influence on electromagnetic field in enclosure by penetrating conductor coupling and its terminal load effect were revealed. The results show that electromagnetic field in enclosure is affected by the combination of penetrating conductor resonance and enclosure resonance. Electric field strength got extremum at resonant frequency. Shielding effectiveness curve of penetrating conductor open at two terminals was close to the curve of penetrating conductor loading but not grounding model. Electric field of penetrating conductor loading grounding directly was significantly lower while resonant frequency was reduced. Changing laws of penetrating conductor loading floating grounding was similar to model of penetrating conductor loading but not grounding in low frequency and similar to model of penetrating conductor loading grounding directly in high frequency. The value of resistance and capacity at terminal of penetrating conductor can also affect electric field.