Study On Crosstalk In High-speed Passive Electric Backplane

Passive electric backplane consists of PCB and connectors, is the most complex case in high-speed board-level interconnect systems.In the backplane interconnect, Crosstalk is one of the most important and critical issue of many signal integrity problems, which exists in the places such as chip, package, PCB and connectors and so on.With the promotion of signal transmission rate, crosstalk worse,and even canses system failure. At present, crosstalk in backplane interconnect has not yet attracted enough attention,and suppressing crosstalk still stays in the stage with experience.In recent years,circuit simulation tools based on Electromagnetic have made great progress in many aspects such as functionality,performance and accuracy.Therefore,exploring the physical mechanism of crosstalk based on elecreomagnetic simulation software,and proposing new crosstalk suppression scheme,thereby providing effective guidance for the design of high-speed circuit is extremely urgent and necessary.Focused on the crosstalk issue in the high-speed backplane interconnect, in-depth and detailed studies are conducted, involving the crosstalk theory and assessment method research,modeling and simulation optimization of the interconnect structure, research of crosstalk suppression methods,simulation and test of backplane interconnect full link and so on.The main work includes:(1) Analyze crosstalk coupling mechanism, time-frequency-domain simulation process and evaluation methods of crosstalk in detail.(2) Explore influence of the basic elements of PCB design on crosstalk.(3) Present a rectangular-shaped resonators method to suppress crosstalk.Verify the effectiveness of the method for inter-microstrip and stripline crosstalk suppression by simulation, and study the impact of structural parameters of the rectangular-shaped resonator on near-end crosstalk.(4) Simulate and optimize the design of connector on the high-speed backplane to reduce crosstalk.Optimize connector pin assignments,including the signal/ground pin allocation and TX/RX distribution;do series of analysis,modeling and simulation for the vias which are used to crimp the connector and stubs, then study the possibility of reducing crosstalk by optimizing these structures.(5) Combined with previous crosstalk suppression research and the demand for engineer, design a set of 25 G backplane experiment systems.On the basis of studying backplane specification IEEE802.3bj/D1.3 and OIF-CEI-03.0, make use of the Matlab to program the calculation process of COM and ICN.Construct the full link simulation models and test benches for 25 G backplane experiment system, and verify the system by simulation and test.Based on this subject, provide a lot of valuable design guidances for the development of follow-25 G transmission system.