Study On Electric Field Distribution In The Cavity Under External Field Irradiation

The ability of a large number of electronic and electrical equipment systems to cope with strong electromagnetic environment during normal operation is increasingly weak.Electromagnetic shielding is one of the effective ways to cut off external electromagnetic interference.When the external field is irradiated,the electromagnetic energy coupled into the cavity through the slot-hole coupling channel and through the cable coupling channel will produce a larger field intensity due to the electromagnetic reverberation characteristics of the cavity,which seriously threatens the normal operation of the key electronic equipment in the cavity.Therefore,it is of great significance to study the electric field distribution in the cavity under external field irradiation.The main research contents of this paper are as follows:1.Cavity field distribution analysis scheme.Firstly,the electromagnetic reverberation of the simulated cavity is determined by the reverberation condition,and the electromagnetic reverberation frequency of the simulated cavity is determined by the experimental method.Then based on the generalized extreme value distribution theory,the maximum field intensity in the cavity under the action of internal field source is modeled and the experimental results are analyzed.Finally,the analysis scheme of the electric field distribution in the cavity under the action of external field is given.2.Pore-slot coupling based on equivalent transmission cross section.Firstly,the equivalent transmission cross section of the hole slot is defined and the shielding efficiency of the cavity is defined.Then the equivalent transmission cross-sections of circular and rectangular holes are analyzed by using the nested reverberation chamber method.Finally,based on the test results of the equivalent transmission cross section of the rectangular slot,the calculation results of the cavity shielding efficiency defined by the equivalent transmission cross section and the cavity shielding efficiency defined by the generalized extreme value distribution are compared and analyzed.3.Equivalent modeling of through-line cable coupling.Firstly,the coupling process through the cable is analyzed,and each coupling loop is modeled and calculated.Then the coupling of field lines in reverberation chamber is simulated and verified by experiments.The results show that the inductive current and reverberation field of cable shield have similar statistical distribution characteristics under the irradiation of statistical uniform field.4.The field inside the cavity irradiated.Firstly,the electromagnetic energy coupled into the cavity by the hole and the cable coupling channels on the cavity is calculated.Then the electric field distribution in the cavity under external field irradiation is analyzed by using the nested reverberation chamber method.The results show that the electric field in the undermode section deviates greatly from the ideal Rayleigh distribution statistics.In a fully stirred electromagnetic environment,the measured samples obey Rayleigh distribution statistics,independent of the configuration of the test cavity.The maximum value of the measured sample is closely related to the resonant mode of the cavity.