光模块中刚柔线路板电连接宽带阻抗匹配研究

Research on Broadband Impedance Matching of Rigid-flex Printed Circuit Board Interconnection in the Optical Transceiver Module

摘要:

文章分别对光收发组件中50Ω柔性线路板和50Ω刚性线路板,以及25Ω柔性线路板和50Ω刚性线路板间的电互连阻抗匹配进行了设计、仿真与实验验证。对于50Ω50Ω刚柔板的高频连接,通过对其返回路径的通孔位置优化设计,使反射损耗S11在高频段降低约11%,插入损耗S21减小19%;对于25Ω50Ω刚柔板的高频连接,提出新的优化方式:在硬板信号线的金手指上做通孔设计,并提取该结构的寄生参数,构建电路模型。该结构大幅提高了连接处容性阻抗,降低了阻抗失配,使得S11在高频段降低约38.2%,S21减小约34%。提出的柔性线路板与刚性线路板的电互连方式,能实现传输线间的阻抗匹配,减小信号反射和插入损耗,提高光模块传输质量,对于光器件的接入具有较大应用价值。

Abstract:

This study mainly focuses on the design, simulation and verification of impedance matching of the rigid-flex printed circuit board interconnections, including 50Ω flexible PCB and 50Ω rigid PCB, as well as 25Ω flexible PCB and 50Ω rigid PCB. For 50Ω flexible PCB and 50Ω rigid PCB interconnection, the positions of ground vias in the return path were optimized, and reflection loss S11 and insertion loss S21 were reduced by about 11% and 19% respectively in the high frequency band. For 25Ω flexible PCB and 50Ω rigid PCB, a novel structure was presented, in which there were two vias in the high-speed signal transmission line of the PCB. Capacitance was increased effectively because of the vias and ground planes. S11 and S21 were reduced by about 38.2% and 34% respectively in the high frequency band. The connection structure of the rigid-flex PCB reported in this article, can improve signal quality of the optical transceiver module, and shows broad application prospects .