| As electronic technology is developing toward high frequency, high-speed, high sensitivity, high reliability, multi- function and miniaturization, electromagnetic interference modern electronic equipment increases rapidly. Electromagnetic compatibility(EMC)means the coexistent state o f various electro or electric systems,that every electronic equipment can function normally. EMC is an important quality specification for electronic equipment,which ensures the system working efficiently and improves the reliability of the system. Electro magnetic compatibility had drawn much great attention from industry,research institutions,becoming international mandatory standard in electronic product,having taken by many countries. In problems of electromagnetic compatibility shielding is thought as o ne of the three major resolution means,attracted much concern from researchers.In the electromagnetic compatibility(EMC) design to equipment and system,metallic conductor is widely used to shield from electromagnetic interference(EMI), and shielding is a main technique. To most electronic equipment, it is hard to meet the requirement of EMC without shielding measurement. However,due to the various needs such as input and output connections,ventilation panels,etc. There are apertures or slots on the conducting shielding inevitably. Theses apertures or slots are the main factor to influence the shielding performance of system. So,to EMC forecasting and design of the electronic devices and system,it will be of high practical significance to understand the mechanism of electromagnetic scattering,transmitting and coupling through the apertures on the metal ic shield.In this paper, the equivalent transmission line method, on the opening hole for electromagnetic shielding cavity rectangular metal hole arrays and double shielding structure shielding effectiveness was evaluated and analyzed using Matlab simulation calculations. Details are as follows: First, M.P.Robinson, who proposed a basic theoretical hole rectangular cavity transmission line models are introduced and calculate hole rectangular cavity shielding effectiveness derivation formulas. Model for the problem not considered in the direction of polarization of incident plane wave, on the basis of a complete analysis of the incident plane wave and deduced for any direction of polarization condition, shielding effectiveness of the shield cavity calculation formula. Calculated and analyzed by parsing apertures size, hole shape, bore hole spacing array and the polarization direction of the external factors such as the incident electromagnetic wave shielding effectiveness of the cavity, summarizes the conclusions of a number of reinforcement design techniques shield cavity. Then to further promote the study of metal shielding layer shielding effectiveness bolt cavity equivalent circuit model double metal shielding chamber deduced quickly calculate the double metal cavity shielding effectiveness of analytical expressions, also studied the position of the hole and other effects of shielding effectiveness. |
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