高速印刷电路板中电磁带隙结构的同步开关噪声抑制和传输特性分析

Analysis of the Electromagnetic Band-gap Structure for Simultaneous Switching Noise Suppression and Transmission Characteristic in High-speed Printed Circuit Board

该文从频域和时域两方面对一种正六边形贴片的电磁带隙(EBG)结构进行了特性分析和研究。利用等效电路理论分析和研究了贴片边长、贴片间距和过孔半径对该结构的带隙和传输特性的各自不同的影响,得到并验证了准确估算不同贴片边长带隙的上、下限频率和带宽的数学表达式。研究表明可以通过贴片间距来改变带宽,但不影响带隙左侧特性,过孔半径的缩小会导致带隙左移并变窄。最终分析了以EBG结构为返回路径的信号线的时域特性,实验证明EBG结构的周期越小,信号的传输质量越差。

The characteristics of the Electromagnetic Band-Gap （EBG） structure composed of regular hexagonal patches is analyzed in the frequency domain and time domain. Respective influences of the side length of patches, space between patches and the radius of vias on the band-gap and transmission characteristics are investigated from the theory of the equivalent circuit. Mathematical expressions which estimate accurately the upper and lower cutoff frequency and bandwidth of the band gap for different side lengths of patches are obtained and verified. Studies show that space between patches changes the bandwidth, but has no influence on the characteristics of the left part of the band gap. When the radius of vias is reduced, the band-gap shifts left and becomes narrow. Finally, The time-domain characteristic of the signal transmission line using EBG structure as a return path is also analyzed. Experiments show that the smaller the period of structure, the worse the signal quality.