Summary: | 碩士 === 國立交通大學 === 電信工程系所 === 97 === In general, it is thought that the metallic enclosure has the functions of shielding and EMC. However, many scientific studies on simulations and measurements indicate that at a metallic enclosure with apertures, the circuit inside the enclosure cannot be shielded completely at peculiar frequencies; moreover, there will be a stronger field at certain positions than when there is no shielding, which may probably cause extra interference in the circuit. It is because through the apertures the exterior electromagnetic field will couple with the cavity, and excite resonance in the cavity.
In this thesis, we explain the definition of shielding effectiveness and the electromagnetic structure first. Secondly, the basic FDTD method and the CST simulator are introduced. Finally, the effects of various factors upon shielding effectiveness of a rectangular metallic enclosure with apertures are researched by using above methods.
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