Analysis Of The Effect Of Aircraft Cable Shield Termination Process Specification On Shielding Effect

With the development of more-electric aircraft,the electromagnetic environment on aircraft has become increasingly complex.In order to meet the requirements of electromagnetic compatibility standards,shielded cables are widely used in aircraft,and the cable shield is properly grounded according to the shield termination process standard.Different shield termination requirements and methods of the shield termination process standard will affect the shielding effect of shielded cables.At present,domestic shield termination process standards for aircraft cables mainly draw on foreign related standards,and there is a lack of theoretical and experimental research related to standard formulation.Therefore,it is of practical engineering significance to investigate the effect of the shield termination process on the shielding effect of cables.Transfer impedance and crosstalk are used to reflect the difference in shielding effect of cables with different shield termination methods.Firstly,based on the definition of the shield transfer impedance,the transfer impedance of lead wires and the transfer impedance of the shielded cables grounded through lead wires ware given.Then,the crosstalk model of shielded cables with 360-degree grounded and the crosstalk model of shielded cables with lead wire grounded ware obtained based on the transmission line theory,and the numerical simulation models for crosstalk prediction ware established in CST cable studio.Finally,the transfer impedance of shielded cables with different shield termination methods was measured by the line injection method,and the crosstalk voltage was obtained by the scattering parameters postprocessing,which ware measured by a vector network analyzer.The research shows that the transfer impedance of shielded cables terminated by lead wires is mainly determined by the transfer impedance of the lead wire section,and the effect of the lead wire grounding position on crosstalk transfer ratio is the most obvious,which can reach 20 d B between different grounding positions.The research enriches the application of transfer impedance and crosstalk in the evaluation of the shield termination process.