Research On Test Standards And Applicability Of Shielding Shell And Conductive Gasket Shieding Effectiveness

With the rapid development of electronic science and technology and the increasingly harsh electromagnetic environment,shielding technology is one of the most commonly used measures to suppress radiation interference.Among them,shielding shells and conductive gaskets are the most widely used.In order to meet the needs of measuring the shielding performance of various shielding shells and conductive gaskets,some standards have been formulated at home and abroad for them.However,for the same object,the standards and regulations are not the same,so it needs to be analyzed and studied.For the shielding shell standard,according to the internal radiation source method and the external radiation source method specified therein,the theoretical models of the ideal dipole antenna excitation are established based on the Bethe's small hole theorem,and the actual models are established using the full-wave simulation software HFSS,and using them compares the difference in shielding effectiveness obtained by the two methods,finally analyzes the influence of the antenna position on the difference between the two methods.The results obtained show that the shielding effectiveness difference obtained by the method of internal and external radiation source is small,and there is no significant difference between the two methods when the position of the transmitting and receiving antenna is changed.However the position of the transmitting and receiving antenna has a great influence on the shielding effectiveness.For the conductive gasket shielding performance test standard SAE ARP6248,a set of strip line devices required for the test was designed and manufactured.The designed device can be used in the frequency band 100MHz-18 GHz,which can be used to measure conductive gaskets with a width less than or equal to 10 mm.When using the E5071 C vector network analyzer to measure,it is measured that the designed stripline standing wave ratio is below 1.6,and the designed microstrip line is below 1.9.Before 8GHz,the lowest dynamic range of the stripline device is as high as 80 d B,but gradually decreases after 8GHz,and the lowest dynamic range is55 d B.compared with the existing stripline device,the frequency band is broadened down to100 MHz and its overall minimum dynamic range is increased by 21 d B.For the conductive gasket shielding performance test standards MIL-DTL-83528,SAE ARP1173 and SAE ARP6248,simulations and experiments are used to study the key influencing factors of the shielding effectiveness results obtained by the methods specified in MIL-DTL-83528 and SAE ARP1173,and compared the consistency between the three standards.The results show that: according to the method specified in the standard MIL-DTL-83528,the antenna distance,antenna type and window size all have a certain impact on its simulation and test results;according to the method specified in SAE ARP1173,the simulation results of the transmitting antenna distance and antenna type The impact is not significant.In addition,the comparison of the simulation results of the three methods shows that although the above standards have different resonance points in the shielding effectiveness results due to differences in simulation or test environments,the overall trend of changes is basically the same.