Research On Calculation Method Of Electromagnetic Radiation Of Interconnection Cable

Interconnection cables,as the signal transmission and energy transfer link between electronic devices,are an indispensable part of realizing system functions.They provide a main gateway for radiated interference and play a major role in the electromagnetic compatibility emission affecting the surrounding electromagnetic environment.For the good shielding electronic equipment,the radiation of the cable is usually the main cause of the excessive radiation of the system.Therefore,the research on the calculation method of the electromagnetic radiation of the interconnection cable is very important.Based on the electromagnetic radiation calculation method of interconnection cable,the following research is carried out:(1)Research on calculation method of electromagnetic radiation of non-continuous penetrating cable.This method takes into account the influence of electrical connector on the transmission signal along the interconnection cable in the calculation model.The internal cable,the electrical connector and the interconnection cable is regarded as two-port network,which is cascaded with each other.The transmission parameter model of non-continuous penetrating cable is established.The terminal voltage and current of the cable are determined by solving the equation of chain parameter,and then the current distribution along the cable is determined.Finally,the electromagnetic radiation of the non-continuous penetrating cable is obtained.(2)Research on calculation method of electromagnetic radiation of curved non-uniform cable.In order to solve this kind of problem,the distributed parameters at different positions in the line are analyzed and the bending non-uniform cable is modeled as a cascade of each uniform unit.The current distribution on the cable is approximately solved according to the matrix of the chain parameters of the non-uniform transmission lines.The current elements in each section are decomposed along the coordinate system.Based on the dipole antenna theory,the radiation field of the cable is calculated,and then the validation of the calculation method is confirmed by using CST software.Finally,the parameter model of the example is used to analyze the influence of different parameters on the electromagnetic radiation of the cable,such as the distance height,cable length and radius and so on.(3)Research on calculation method of electromagnetic radiation of non-uniform cable harness with random distribution of wires.The calculation method of electromagnetic radiation of curved non-uniform cable is extended to the electromagnetic radiation of the non-uniform cable bundle with random distribution of wires.Considering the randomness of the wire position in the wire harness,firstly the random position of the Gaussian distribution is generated by using Matlab software,and the position of the wire is determined by using spline interpolation method.Then the non-uniform cable bundle is treated as multi-conductor transmission line with distribution parameters,and it is decomposed as the cascade of uniform sub-segment.In order to simplify the calculation,assuming that there is transposition between the sub-sections of the wire,the transmission parameter distribution of the wire bundle can be calculated,and then the non-uniform multi-conductor transmission line equation is solved.Finally,the radiation field generated by each sub-segment is superposed to obtain the electromagnetic radiation of the multi-core wire with randomly distributed wires.The numerical simulation confirms the validation of the method.