The Analysis Of The Influence Of PCB-level Electrothermal Coupling On The Signal Integrity

With the rapid improvement in the integration of printed circuit board(Printed Circuit Board,PCB)in electronic products,ensuring the integrity of the signal in high speed circuit has become the key to the design of high speed circuit.Meanwhile,the working temperature of PCB has been becoming higher and higher as the function of the device and the layout improved,which could cause that the quality of the signal is the most important issue for producers and users under the influence of temperature.The change of PCB temperature caused by the working of electronic products must be bound to influence the parameters of the material itself,which could affect the performance of high speed circuits at the same time.According to the above,it is necessary to consider the electrothermal coupling for the analysis of the PCB-level signal integrity with high precision.However,most of the traditional electrothermal coupling studies tended to establish coupling variables such as thermal conductivity and electrical conductivity to analyze the coupling analysis between temperature and power distribution network and the signal quality under the influence of electrothermal coupling was rarely considered as the research focus.Therefore,this paper proposes an electrothermal coupling methodbased on the dielectric constant of the research object PCB,which is combined with electromagnetic analysis to explore the effect of temperature change on the PCB-level signal integrity.Firstly,under the terms of the temperature field output based on Workbench,eight groups of experiments with parameterized analysis of dielectric constant are carried out in this paper.According to the analysis,we obtain the regulation of the PCB surface temperature distribution changing with alteration to the relative dielectric constant when PCB works.After that,the paper analyzes the influence of the temperature on the relative dielectric constant of the research object at 20?,100?,110? by measuring,which determines the PCB dielectric-temperature characteristic.Finally,under the condition of variable temperature,the parameterized dielectric constant is used to analyze the evaluation index of signal integrity of the PCB high speed channel,such as insertion loss,return loss and characteristic impedance by electromagnetic analysis based on HFSS.Furthermore,the influence of the temperature on the PCB-level signal integrity of the high speed channel is obtained.