Electromagnetic Interference Modeling And Analysis Methods For The Penetrated Wires In Electronic Devices

With the development of wireless communication technology,a large number of intelligent terminal electronic devices are loaded with wireless communication modules,and some circuits inevitably generate electromagnetic radiation,which makes the internal space electromagnetic field environment more and more complicated.The space electromagnetic field irradiates the penetrated wire used for energy supply and signal transmission,which causes electromagnetic compatibility problems for electronic devices.The traditional electromagnetic interference problem uses experimental methods to carry out repeated tests and rectifications,which has high cost and low efficiency.Therefore,it is very important to use numerical simulation methods to simulate and analyze the electromagnetic interference of the penetrated wire of electronic devices in the concept and design stage.Limited by the complexity of the circuit and the fine structure of the penetrated wire,the existing penetrated wire electromagnetic interference analysis methods still have shortcomings.Therefore,based on the equivalent source model of the electromagnetic radiation of the circuit,this thesis studies the efficient field-circuit hybrid analysis method around the electromagnetic interference problem of two types of typical penetrated wires in electronic device,and provides important technical support for the electromagnetic protection design of electronic devices.The main work of the thesis is summarized as follows:(1)The Equivalent source model of circuit radiation is constructed,and the electromagnetic coupling analysis method of the transmission line irradiated by the equivalent source is studied.Firstly,the equivalent source of electromagnetic radiation is modeled by constructing the Hertz dipole array.Then,according to the transmission line equation,the electromagnetic coupling model of transmission line under the action of Hertz dipole array is established.Using the finite difference time domain(FDTD)method and the automatic mesh generation technology,an efficient field-line coupling analysis method is studied to realize the fast synchronous calculation of the electromagnetic radiation of the circuit and the interference response of the transmission line.The correctness of the algorithm is verified by the corresponding examples,which avoids the direct modeling of the circuit and the transmission line.(2)The field-circuit hybrid analysis method for overhead penetrated wire of electronic device is proposed.Firstly,according to FDTD of thin wire,the equivalent current source model of outer transmission line of overhead penetrated wire is extracted,and the equivalent current source is introduced into inner transmission line as excitation source.Then the field-line coupling algorithm is used to model the electromagnetic coupling of the internal transmission line,and the response of the overhead penetrated wire terminal load is quickly calculated.Finally,the correctness and efficiency of the hybrid analysis method are verified by corresponding examples,and the electromagnetic coupling law of overhead penetrated wire under the radiation field of the circuit is analyzed.(3)The field-circuit hybrid analysis method for discontinuous penetrated wire near the ground of electronic device is studied.Firstly,based on Thevenin's theorem and fieldline coupling algorithm,the equivalent circuit of external transmission line is extracted.Then,the connector and inner transmission line are regarded as cascaded two port network.Based on the two-port network parameter theory,an integrated equivalent circuit model of discontinuous penetrated wire near ground is constructed,and its terminal load response is quickly calculated.Finally,an example is given to verify the accuracy and efficiency of the hybrid analysis method.The hybrid analysis method is applied to the analysis of electromagnetic protection of penetrated wire,and the electromagnetic coupling law of discontinuous penetrated wire near the ground is analyzed.