Simulation Design Of Signal Integrity Of High-Speed Backplane Connector

With the arrival of the 5G era of high-speed,low delay and large connection,electronic equipments or systems are also rapidly stepping into the era of high-speed,miniaturization and integration.It makes PCB board become one of the important components in the electronic industry,and the backplane connector,which plays the role of connecting PCB board and backplane,is significant.When the clock frequency of the signal is getting higher and higher,the problem of signal integrity of the product must be taken into consideration.It may cause instability in the transmission system at best,or make the transmission system unable to continue to work at worst.Therefore,in the design of high-speed PCB system,it is more important to ensure the signal integrity of high-speed backplane connector as the signal transmission bridge.This paper takes the high-speed backplane connector as the research object,designs the internal structure of a high-speed backplane connector,simulates and analyzes its signal integrity parameters,solves the highfrequency signal problem of the connector in the transmission process,reduces the impedance mismatch of the connector,reduces the reflection of each differential transmission pair and the crosstalk between differential transmission pairs,and improves the transmission efficiency.The main contents of the study are as follows:First,this paper expounds the basic knowledge of transmission line and signal integrity,which is the theoretical basis for the subsequent design,simulation and analysis of the high-speed backplane connector.In particular,the signal integrity problem provides important theoretical support for the subsequent analysis of simulation results.Then,in order to ensure the quality of signal transmission,a good physical model must be established.This paper introduces the structure composition and performance index requirements of high-speed backplane connector,and designs and models each component of signal wafer of high-speed backplane connector,including terminal layer,plastic layer,metal shield layer and conductive adhesive layer.After the modeling is completed,the two-dimensional solver PolarSI9000 is selected to verify the characteristic impedance and matching of the designed wafer model to ensure the reliability of the model.Next,According to the target of signal integrity parameters and the hardware requirements of the simulation equipment,this paper selects appropriate simulation software and formulates a complete simulation scheme.The three-dimensional electromagnetic simulation software CST Studio is used to model the high-speed backplane connector wafer,set the parameters before simulation(including unit,frequency range,background material and boundary conditions),set the material properties,set the coaxial port and select the solver.The signal integrity parameters including return loss,insertion loss,near-end crosstalk,far-end crosstalk and TDR impedance are obtained by simulation.Finally,through the comparative analysis of the simulation results and the signal integrity index requirements,the design scheme has been improved or optimized for many times.By changing the dielectric constant and loss factor of the dielectric material,changing the structure size of the signal terminal and changing the structure size of the grounding terminal,a total of six sets of design schemes have been designed and ultimately meet the requirements of the signal integrity index.Compared with scheme 1,the crosstalk and TDR impedance of scheme 6 are improved by at least 25.7%and 9.8%,respectively.According to the design process of six schemes,this paper summarizes six design principles and inspirations for high-speed backplane connectors,mainly by changing the structural dimensions of differential pairs,the structural dimensions of grounding terminals and the dielectric constant or loss factor of dielectric materials to achieve the signal integrity index requirements of high-speed backplane connectors.