Research On Shielding Slits Characteristics And Equivalent Calculation Method

The large-scale application of electromagnetic equipment has caused certain electromagnetic pollution,which has seriously affected human health,information system security and national economic development.The prevention and control of electromagnetic pollution requires the use of a shielding box to effectively shield electromagnetic equipment,but due to the need for ventilation and heat dissipation,there will be aperture arrays in the shielding box,which will cause electromagnetic wave leakage and reduce the shielding performance of the shielding box.In view of the above problems,this paper will take the shielding box with aperture arrays as the research object,analyze the characteristics of the aperture arrays and propose a fast and accurate equivalent calculation method for its shielding effectiveness calculation.First of all,take the shield with slits as the object.The influence of the slit length and width on the shielding characteristics is studied,and the key factor affecting the slit is the length of the slit side perpendicular to the magnetic field direction.Then separately add loss materials to the slit,deepen the slit and double-layer shielding three different schemes to repair,the research results show that the three repair schemes can effectively improve the shielding effectiveness of the shield body,the use of double-layer repair can be extremely improves shielding characteristics.Then take the shield with aperture array as the object.Under the condition that the total area of the small apertures is equal,the influence of the shape and number of the small apertures in the aperture array and the distance between the apertures and the apertures on the shielding characteristics of the shielding body is studied.The research results show that round and square small apertures have better shielding characteristics than rectangular small apertures.Under certain conditions,the more the number of small apertures and the larger the distance between the small apertures and the small apertures,the better the shielding effectiveness.Last,taking the shield with eccentric aperture array as the object,in order to simplify engineering calculation and simulation,an equivalent calculation method is proposed.First convert the aperture array into a single aperture of equal area,and then introduce the scale down factor and the coupling coefficient to correct the impedance of the aperture.Finally,by changing the number of aperture arrays,the position of the aperture arrays and the material of the shielding box,the accuracy of the equivalent algorithm proposed in this paper is verified.Through systematic analysis of the slot characteristics of the shield and the study of equivalent calculation methods,the electromagnetic shielding rules of the shield with aperture arrays are obtained,and the optimal slot shielding scheme can be selected.It provides a certain theoretical basis for the structural design of complex shielding boxes,and has important theoretical and engineering significance.