含贯通线及PCB板开孔腔体的电磁耦合研究

外界能量通过贯通线进入开孔屏蔽体,与PCB上MSL耦合而生成感应电流(Current),加剧了对敏感器件的耦合伤害。故建立含贯通线及PCB板开孔屏蔽腔模型,进行多角度耦合特性计算。在建模有效性验证后,利用有限元法探讨平面波激励下PCB不同模型、MSL上不同端接电阻、贯通线半径、贯通线与腔体壁相接及多贯通线等参数变化对Current的影响规律。结果表明:双介质模型的使用更接近实际PCB 结构对场的影响;两端接电阻取值相差不大条件下,可不考虑与MSL的阻抗匹配,取值也可不相等;Current 数值随贯通线半径的增加而增加;贯通线与腔体壁不同表面相接对应Current幅值要远高于非接触的情况,并会激出新的谐振点。多根贯通线及线间距改变时Current幅值都要高于单线的情况,尤以第一谐振之前更为明显,多线存在不会影响谐振点出现位置。

Study on Electromagnetic Coupling of Slotted Cavity with PenetrativeWire and PCB Plate

The external energy that enters the slotted cavity through the penetrative wire will generate the induction current on the MSL. The coupling damage to sensitive device is increased. The model of the shield cavity with penetrative wire and PCB are established. The coupling calculations are carried out by multi angles. After validating the model validity,the corresponding current variation law due to the parameter variations such as the different PCB models, the different termination resistances, the wire radius, the connection between the wire and the cavity wall and the multi wires are discussed by the finite element method. The results show: the effect for field of the double medium model is closer to the actual PCB structure; the impedance matching with MSL can''t be considered under the condition of little resistance difference, the resistance may not be equal. The current will increase when the wire radius becomes large. The current when the wire is connected with the different cavity surface are much higher than non contact situation, and they will inspire the new resonance points. The current of the multi wires is higher than the single case, it has the same effect when the line spacing changes. It is more obvious especially before the first resonance;The resonance position will not be affected by multi wires.