Study on electromagnetic shield of a lossy shielding screen with apertures

开孔有损屏蔽屏的电磁屏蔽研究

• 批准号: 12831005
• 负责人: YOSHITOMI Kuniaki
• 金额: $ 2.37万
• 依托单位: Kyushu University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12831005/
• 关键词: Electromagnetic shield; Surface impedance; Radiowave absorber; Reinforced concrete; Power frequency magnetic field; 抵抗膜

Shielding effect of electromagnetic shielding plates with apertures, a simple model of a shielding case of an electric device, was studied both analytically and experimentally. In the analytical study, we obtained a Green's function which represents the fields radiated from a source on a lossy ground plane. A Green's function for the field in a waveguide was also obtained. A surface impedance boundary condition was introduced to simplify the boundary conditions for the lossy surfaces of the shielding plates. By using these Green's functions, analytical results of the field scattered by a slot in a lossy screen were obtained. It was found that a thin magnetic coating reduces the transmission power through a slot for the frequency higher than the resonant frequency, while for the frequency lower than the resonance the coating increases the transmission power. This frequency dependence of the transmission power through a slot is important when we use a magnetic coating material to reduce electromagnetic wave leakage through a slot.In the experimental study, the scattered fields by a slot in a metal plate covered with an absorbing material were measured. The results are generally consistent with analytically predicted one.As a study of shielding of an actual electromagnetic field, measurements of power frequency magnetic fields in an apartment building were performed. An effective technique to reduce power frequency magnetic fields were proposed.

对电气设备屏蔽罩的一种简单模型--带孔电磁屏蔽板的屏蔽效果进行了理论分析和实验研究。在解析研究中，我们得到了一个绿色函数，它代表了从一个源上的有耗地面辐射场。还得到了波导中场的绿色函数。引入表面阻抗边界条件，简化了屏蔽板有耗表面的边界条件。利用这些绿色函数，得到了有耗屏缝隙散射场的解析解。有人发现，薄的磁性涂层降低了传输功率通过槽的频率高于谐振频率，而低于谐振的频率的涂层增加了传输功率。当我们使用磁性涂层材料来减少通过缝隙的电磁波泄漏时，通过缝隙的传输功率的频率依赖性是重要的。在实验研究中，测量了覆盖有吸收材料的金属板中的缝隙的散射场。作为对实际电磁场屏蔽的研究，对某住宅楼的工频磁场进行了测量。提出了一种降低工频磁场的有效方法。

项目成果

K.Yashitomi: "Radiation from a slot aperture in a lossy ground plane"Proceedings and Abstracts of 2001 Far-Eastern School-Seminar on Mathematical Modeling and Numerical Analysis (FESS-MMNA'01). FESS MMNA'01. 227-232 (2001)

K.Yashitomi：“有损地平面中缝隙孔径的辐射”2001 年远东学校数学建模和数值分析研讨会论文集和摘要 (FESS-MMNA01)。

K. Yoshitomi: "Radiation from a slot aperture in a lossy ground plane"Telecommunication and Radio Engineering. Vol. 58. 85-92 (2002)

K. Yoshitomi：“有损地平面中缝隙孔径的辐射”电信和无线电工程。

K.Yoshitomi: "Radiation from a slot in an impedance surface"IEEE Transactions on Antennas and Propagation. 49. 1370-1376 (2001)

K.Yoshitomi：“来自阻抗表面槽的辐射”IEEE Transactions on Antennas and Propagation。

K.Yoshitomi: "Radiation from a slot aperture in a lossy ground plane"Telecommunications and Radio Engineering. 49. 85-92 (2002)

K.Yoshitomi：“有损地平面中缝隙孔径的辐射”电信和无线电工程。

K.Yoshitomi: "Radiation from a slot aperture in a lossy ground plane"Proceedings and Abstracts of 2001 Far-Eastern School-Seminar on Mathematical Modeling and Numerical Analysis (FESS-MMNA'01). FESS-MMNA'01. 227-232 (2001)

K.Yoshitomi：“有损地平面中缝隙孔径的辐射”2001年远东学校数学建模和数值分析研讨会论文集和摘要（FESS-MMNA01）。