印刷电路板影响信号完整性的频域分析

理论上定性分析了印刷电路板(PCB)印制线拐角的特性阻抗不连续性,及其对信号完整性的影响。利用CSTMICROWAVE STUDIO5.0高频三维电磁场仿真软件,通过数值计算比较了90°弯曲的任意几何结构印制线拐角的信号传输和反射特性,并且将数值结果和现有文献的结果进行了比较,部分数值结果与文献结果一致。数值计算结果表明:印制线拐角传输特性改善的次序依次为:直角圆角内外45°斜切45°外斜切,最佳几何结构为直角弯曲45°外斜切;小于8GHz的频率范围内,直角弯曲45°外斜切拐角的最佳斜切率约为0.535。

Frequency-Domain Analysis of Impact of PCB on Signal Integrity

Qualitative analysis of characteristic impedance discontinuity of trace corners on printed circuit board （PCB） as well as its impacts on signal integrity is provided. By using of high frequency （HF） 3D electromagnetic filed simulation software CST MICROWAVE STUDIO 5.0, comparison between signal transmission and reflection characteristics of 90° trace corners with different geometry structures are made through numerical calculation; comparison between the calculation results and results given in some reference verify that some numerical calculation resuits are consistent with the results provided in the reference. The numerical calculation results show that transmission characteristics of trace corners on the PCB are respectively in following orders： right angle 〈 round angle 〈 internal and external 45° chamfered 〈 external 45° chamfered, the optimal geometry structure is right angle with external 45° chamfered; and if the frequency is less than 8GHz, optimal chamfered rate of the right angle with external 45° chamfered is about 0. 535.