PCB传输线间串扰抑制方法分析

Analysis of Crosstalk Reduction in Transmission Lines on PCBs

研究数字电子技术设备中,串扰是印刷电路板(PCB)上电磁兼容的重要内容之一。为了抑制PCB传输线间串扰,提高系统信号准确性,消除噪音,通常在传输线间插入一列用金属填充的、顶端用微带连接的接地柱线(简称保护带)。由于加有保护带的传输线系统结构复杂,理论分析比较困难,利用网络级联的方法对加有保护带的传输线建模进行分析。计算分析结果表明,加入保护带能有效地抑制线间串扰,保护带参数(接地柱间距、半径)的变化对串扰抑制有明显影响。研究对工程中正确设置保护带以降低串扰提供了必要的参考。

Crosstalk is one of the important EMC problems on PCBs. To reduce the crosstalk between transmission lines,metal filled via holes which were connected by microstrips on the top of via holes and grounded （guard trace） were inserted between the transmission lines,the circuit concept approach for transmission line sections and impedance modeling for via hole sections are used to simulate the guard trace. The results show the effectiveness of crosstalk suppression,the significantl effects of guard trace on the crosstalk suppression with parameters （hole spacing,radius） changing. The study provides the essential reference for setting up guard trace in order to lower crosstalk in the engineering project.