| Modern electronic equipment systems are vulnerable to be interfered and damaged by the electromagnetic pulse.In order to evaluate the security and electromagnetic sensitivity(EMS)of electronic equipment system under electromagnetic pulse interference,and ensure the normal operation of the system,it is necessary to utilize the electromagnetic simulation technology to predict the coupling response characteristics of the system under the electromagnetic pulse interference.However,due to the high integration of electronic equipment system-level platform,complex electromagnetic coupling paths and many kinds of electromagnetic coupling elements,a single electromagnetic simulation approach cannot realize the electromagnetic compatibility and electromagnetic interference coupling simulation of the overall system-level platform.Therefore,this dissertation devotes to the in-depth study on the efficient system-level hybrid simulation method required for the electromagnetic pulse coupling analysis of electronic equipment system-level platform.The main study contents of this dissertation are as follows:(1)Element decomposition and system modeling of electromagnetic pulse coupling for system-level platforms.Firstly,aiming at the complex coupling paths,many kinds of coupling elements and various structural factors of electromagnetic pulse interference of the system-level platform,the time-domain and frequency-domain characteristics of typical electromagnetic pulse signals and their electromagnetic coupling characteristics to complex system-level platform are analyzed.Based on the electromagnetic topology method,the system modeling analysis of electromagnetic pulse coupling of the system-level platform are carried out,then the key coupling elements are determined,and the simulation calculation methods that need to be combined to complete the electromagnetic pulse coupling analysis of system-level platforms are proposed.(2)Study on hybrid FDTD method of electromagnetic pulse coupling of antennas mounted on platform.Aiming at the multi-scale meshing problem of electromagnetic pulse coupling of antennas mounted on platform,a hybrid FDTD method combining improved non-uniform mesh FDTD and improved antenna feeding structure model is studied.Firstly,the nonuniform mesh technology of FDTD modeling is analyzed,and an improved interpolation technology to reduce the boundary error of non-uniform mesh is proposed.Based on the improved non-uniform FDTD,fine meshes can be used in the local fine structure of the antenna and coarse meshes can be used in other areas,thus avoiding using uniform fine meshes in the whole simulation domain and occupying a lot of computing memory by the traditional FDTD.Then,an improved feeding model is established for the feeding structure of antennas,which avoids the fine mesh division for the feeding structure.Finally,by effectively combining the non-uniform mesh FDTD and the improved feeding structure model of antennas,a hybrid FDTD method suitable for the electromagnetic pulse coupling analysis of antenna mounted on platform is established.Based on the hybrid FDTD method,the directional electromagnetic characteristics and electromagnetic pulse coupling response of antennas mounted on the platform are analyzed and studied.(3)Study on system-level field-line hybrid simulation method for multi-coupling paths.In order to efficiently realize the comprehensive simulation analysis under the multi-coupling paths synthesis of system-level platform,and avoid multiple numerical modeling of different incident scenes of antenna electromagnetic pulse coupling,a system-level field-line hybrid method integrating FDTD,improved thin wire model,antenna coupling analytical model and transmission line equation(TL)is proposed.In this hybrid method,based on the reciprocity theorem,the theoretical calculation model of antenna electromagnetic coupling reception is established,and a fast analytical calculation method based on antenna-coupling receiving model is proposed,which avoids multiple numerical modeling and simulation of different antenna-coupling scene analysis.On this basis,the nonuniform hybrid FDTD method is combined with the antenna-coupling receiving model to further realize the fast calculation of the electromagnetic pulse coupling response of complex antenna structure.Aiming at the important coupling element of interconnection transmission cables in the cabin of the system platform,a hybrid FDTD method for electromagnetic coupling analysis of unshielded multi-conductor cables is given.Furthermore,a FDTD modeling method for unshielded cables with arbitrary layout is proposed to realize its electromagnetic coupling analysis.For the electromagnetic coupling analysis of shielded cables in the cabin,a hybrid FDTD-TL method is established by integrating the improved thin wire model and the transfer impedance model.Through the simulation analysis to the electromagnetic pulse coupling response of the complex system-level platform,and compared with the numerical simulation results of commercial software,the efficiency and accuracy of the system-level field-line hybrid method are verified.(4)Study on system-level FDTD-SPICE field-circuit hybrid simulation method.The systemlevel field-line multi-coupled path hybrid simulation method can efficiently solve the coupling response of system terminals,but it is only suitable for solving simple linear terminal circuit responses,while the modeling of non-linear components and complex terminal circuits is not easy to achieve.Therefore,in order to realize the field-circuit hybrid analysis of complex circuit at the terminal of system-level platform,a novel field-circuit hybrid simulation method integrating FDTD and SPICE equivalent circuit is proposed.Based on the antenna-coupling receiving model,by fitting the frequency-domain characteristic parameters of the antenna with rational function,a time-domain analysis method based on equivalent SPICE circuit modeling for the antenna-coupling receiving is proposed.The transient coupling response of the antenna is directly obtained based on SPICE circuit simulation.For the transmission cables,improved SPICE circuit models of unshielded cables with arbitrary layout and shielded cables are proposed.The system-level SPICE circuit model is formed by combining the front-door coupling and the back-door coupling equivalent SPICE circuit.The efficient field-circuit simulation is achieved by combining FDTD to calculate the spatial electromagnetic field and extract the equivalent excitation source of the system-level SPICE circuit.Based on the system-level FDTDSPICE field-circuit hybrid method,the applications of complex filter protection circuit and electromagnetic pulse protection circuit for the system terminal are simulated and analyzed.(5)Experimental study on electromagnetic pulse coupling of antennas mounted on the platform.Because the whole electromagnetic pulse coupling test of system level platform is difficult,several typical antennas mounted on the system level platform studied in this dissertation are selected for electromagnetic pulse interference coupling test,and the coupling voltage responses of the antenna mounted on the local platform structure are obtained under the irradiation of ultra-wide spectrum high power microwave.The hybrid FDTD method for EMP coupling of antenna mounted on platform proposed in this dissertation is used to simulate the corresponding test scenarios of each antenna,and the simulation results are compared with the test results to verify the accuracy of the method.Based on the above study contents,the main innovations of this dissertation are as follows:(1)Studied a hybrid FDTD method for calculating the electromagnetic pulse coupling response of the antenna mounted on the platform.A hybrid FDTD method combining improved non-uniform grid FDTD technology and improved antenna feed structure model is studied for multi-scale simulation modeling of electromagnetic pulse coupling response of antenna mounted on platform.Compared with the traditional FDTD method,this hybrid method avoids the increase of the number of meshes due to the existence of the small antenna structure,and greatly improves the calculation efficiency.(2)Proposed a field-line hybrid simulation method for calculating the comprehensive response of system-level platform.For the system-level platform including multiple complex coupling elements such as platform cabin,antenna,cable and terminal load,a system-level field-line hybrid method integrating FDTD,improved thin line model,antenna-coupling analytical model and transmission line equation is proposed.Compared with the separate modeling for the whole system with numerical simulation method,this hybrid method reduces the difficulty of system-level modeling,improves the ability of co-simulation,and efficiently realizes the comprehensive simulation analysis of multi-coupling paths of system-level platform by combining the numerical method with the analytical calculation method of different coupling elements.(3)Proposed a FDTD-SPICE field-circuit hybrid simulation method for solving the response of terminal complex circuit.In order to extend the comprehensive analysis of complex circuits in system-level terminals,based on system-level field-line hybrid method,an FDTD-SPICE field-circuit hybrid method for system-level platform is proposed.In this method,a system-level equivalent SPICE model combining antenna and cable is proposed,which can solve the front-door coupling and back-door coupling response of the system simultaneously.The FDTD is utilized to calculate the space electromagnetic field,which is then extracted as the equivalent excitation source of system-level SPICE circuit to realize the efficient simulation calculation of field-circuit combination.Compared with the single numerical simulation approach,this method not only simplifies the modeling of system coupling elements and improves the calculation efficiency,but also provides an effective modeling method for realizing the more in-depth field-circuit simulation analysis to terminal complex circuits. |
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