电磁脉冲与开孔腔内PCB板级MSL间的耦合研究

The Coupling Study between PCB Board-Level MSL in Slotted Cavity and Electromagnetic Pulse

因PCB上微带线(MSL)与外界电磁能量耦合而生成感应电流(Current),会对敏感器件造成耦合伤害。而目前对此研究的关注度不够,故以带拐角MSL的PCB板内置于开孔屏蔽腔为研究对象,以Current计算为主要切入点,进行多参数耦合特性计算。先建立相应数值模型并验证建模方法有效性后,外置平面波激励源,利用有限元法考察不同计算位置、有无屏蔽腔、MSL夹角大小及拐角补偿等参数变化对电流的影响。结果表明:直MSL上不同计算位置对Current影响不大,其数值都要比MSL弯折时要大,两者差值随频率增加而逐渐减小;谐振点处腔体抑制效果会被弱化甚至完全失效;MSL与电场E平行放置时,迹线需布成短线,MSL与电场E垂直放置时,迹线可布成长线;MSL宽度增加,电流数值会增加但趋势减缓。拐角补偿方法对提高信号完整性(SI)有效,但对降低电磁耦合作用有限。不会影响谐振点出现位置是上述多参数研究的共性结果。

The current produced by the coupling between the MSL and the external electromagnetic energy will cause damage to sensitive devices. But the research is not enough at present. The PCB board with a corner MSL in the slot shelled is built as the research object. Using current as the main entry point, the multi parameter coupling is calculated. First, the corresponding model is established and validated. The plane wave excitation is used to investigate the influence for current. The Parameters include the different positions, whether there is a shielding cavity, the MSL angle size and the corner com- pensation. The results show： the currents of the different positions have little effect for the straight MSL. The value of straight MSL is greater than the one of bend MSL, and the difference decreases with the increasing frequency. At the resonance point, the suppression effect of the cavity is weakened or even completely ineffective ; When MSL and E are placed in paral- lel, it can be arranged into short trace, When MSL and E is placed vertically, it can be arranged into long trace. With the increase of MSL width, the current will increase, but the trend will slow down. The corner compensation is effective for im- proving SI, but it is limited for the electromagnetic coupling. The resonant point position is not affected due to the multi pa- rameters variation is the common result.