Study On An Efficient Simulation Method For Analyzing EMI Effect Of Transmission Line Networks Of Communication Systems

With the rapid development and wide use of typical communication systems,it has been attracted more and more attention to the electromagnetic compatibility(EMC)and electromagnetic interference(EMI)features due to the complex and poor electromagnetic environment in these structures.Generally,these electronic structures include antenna,cable network,terminal circuit load,and so on,and the electromagnetic interaction mechanism is very complex.In order to accurately model the energy coupling process and their surge effects among typical structure,antennas,transmission line network,and terminal circuit modules,a hybrid method should be presented which must be compatible with the field,transmission line,and circuit numerical solvers.Based on the electromagnetic protection of typical electronic information system,this paper devotes to the efficient and accurate numerical methods of its surge effect simulation and prediction so as to reveal the transmission law,coupling process,and especially their terminal transient responses introduced by the external electromagnetic pulses(EMPs),among the antenna,cable network,and the apertures of the typical cabin.For the simulation challenges introduced by a complex,multi-scale,and multi-stage coupling system,our research will be focused on three parts which are shown as follows.Firstly,we propose a FDTD method of two-conductor transmission line to deduce the processing when transmission line terminating with impedance and capacitance,and the distribution parameters of the transmission line is studied.Secondly,according to the complex characteristics of the typical communication system,this paper proposes a hybrid finite difference time domain method for building equivalent model of the internal cable network,and the characteristic equation of the transmission line with different loads is solved by introducing the MNA(Modified Nodal Analysis)method.The transient voltage and current response at the termination is obtained and compared with PSPICE to verify the accuracy of the proposed method,so as to realize the co-simulation of whole communication system.Finally,by studying the coupling among the external EMPs,the antennas,the cable network,as well as the internal circuits,we introduce some reasonable boundary conditions to connect the different coupling regions.Then,a novel hybrid field-line-circuit method,which takes into account the interaction between the field and the antennas,the field and the cables,the antennas and the cables,and the cables and the circuits,is proposed to predict and analyze the surge effects caused by all types of coupling on different levels.The research process can be summarized as three parts:1)full-wave electromagnetic simulation;2)transmission line equations;3)the equivalent simulation of circuit module.Furthermore,the electromagnetic safety threshold assessment of the typical electronic information system can be obtained and the corresponding protection recommendations should be given as theoretical and technical support for the top-level quantization of the electromagnetic environmental effects of the typical electronic information systems design.