Acta Metallurgica Sinica(English letters) ›› 2008, Vol. 15 ›› Issue (4): 81-85.doi:

• Electromagnetic Compatibility • 上一篇    下一篇

Shielding effectiveness of rectangular cavity made of a new shielding material and resonance suppression

汪柳平   

  1. Aisino Corporation, Beijing 100195, China
  • 收稿日期:2008-04-10 修回日期:1900-01-01 出版日期:2008-12-30
  • 通讯作者: 汪柳平

Shielding effectiveness of rectangular cavity made of a new shielding material and resonance suppression

WANG Liu-ping   

  1. Aisino Corporation, Beijing 100195, China
  • Received:2008-04-10 Revised:1900-01-01 Online:2008-12-30
  • Contact: WANG Liu-ping

摘要:

New shielding material has become an alternative to traditional metal to shield boxes from electromagnetic interferences. This article introduces the theory of transmission line method to study the shield boxes made of a new sort of material, and then expands the fundamental formulas to deal with the cases of multiple holes and polarization with arbitrary angle. By means of genetic algorithms with the aid of a three dimensional simulation tool, the damping of electromagnetic resonances in enclosures is researched.
The computation indicates that under resonant frequency, electromagnetic resonance results in low, even negative shielding coefficient; whereas, for the same areas, shielding effectiveness of a single hole is worse than that of multiple holes. Shielding coefficient varies when polarization angle increases, and the coupled field through the rectangular aperture with the long side parallel to the thin wire is much weaker than that with the long side vertical to the thin wire. By using the metallic-loss dielectric layer of optimized calculation on the internal surface of the cavity, the best result of resonance suppression has been realized with the same thickness of coating. Finally, according to the calculation result, suggestions for shielding are proposed.

关键词:

apertures,;shielding;effectiveness,;resonance;suppression

Abstract:

New shielding material has become an alternative to traditional metal to shield boxes from electromagnetic interferences. This article introduces the theory of transmission line method to study the shield boxes made of a new sort of material, and then expands the fundamental formulas to deal with the cases of multiple holes and polarization with arbitrary angle. By means of genetic algorithms with the aid of a three dimensional simulation tool, the damping of electromagnetic resonances in enclosures is researched.
The computation indicates that under resonant frequency, electromagnetic resonance results in low, even negative shielding coefficient; whereas, for the same areas, shielding effectiveness of a single hole is worse than that of multiple holes. Shielding coefficient varies when polarization angle increases, and the coupled field through the rectangular aperture with the long side parallel to the thin wire is much weaker than that with the long side vertical to the thin wire. By using the metallic-loss dielectric layer of optimized calculation on the internal surface of the cavity, the best result of resonance suppression has been realized with the same thickness of coating. Finally, according to the calculation result, suggestions for shielding are proposed.

Key words:

apertures;shielding effectiveness;resonance suppression