Shielding effectiveness of infinite metal plate with finite thickness at oblique incident and arbitrary polarizations

Author(s):  
Yang Jing ◽  
Sun Beiyun ◽  
Zhu Zhizhen ◽  
Shi Yuewu
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Duy Tung Phan ◽  
Chang Won Jung

AbstractAn electromagnetic pulse (EMP) with high energy can damage electronic equipment instantly within a wide range of thousands of kilometers. Generally, a metal plate placed inside a thick concrete wall is used against an EMP, but it is not suitable for an EMP shielding window, which requires not only strong shielding effectiveness (SE) but also optical transparency (OT). In this paper, we propose a very thin and optically transparent structure with excellent SE for EMP shielding window application. The proposed structure consists of a saltwater layer held between two glass substrates and two metal mesh layers on the outside of the glass, with a total thickness of less than 1.5 cm. The SE and OT of the structure are above 80 dB and 45%, respectively, which not only meet the requirement of EMP shielding for military purposes but also retain the procedure of good observation. Moreover, the OT of the structure can be significantly improved using only one metal mesh film (MMF) layer, while the SE is still maintained high to satisfy the required SE for home applicants. With the major advantages of low cost, optical transparency, strong SE, and flexible performance, the proposed structure can be considered a good solution for transparent EMP shielding windows.


The induction of eddy currents in metal plates which are subjected to alternating magnetic fields has been discussed by Clerk-Maxwell, J. J. Thomson and many others. When an alternating magnetic field is produced normal to the surface of a metal plate, eddy currents are induced at the surface of the plate, which gradually penetrate its interior, the current dying away as it penetrates more deeply into the metal. The diffusion of the currents into the plate depends upon the self-induction and resistance of the paths along which they flow, and can be calculated by the same kind of formula as is used for determining the conduction of heat through a metal slab.


2012 ◽  
Vol 538-541 ◽  
pp. 655-659 ◽  
Author(s):  
Long Fei Liu ◽  
Qi Shan Zhang

Due to obvious predominances of airing, daylighting and so on, metallic mesh is widely applied in electromagnetic shielding projects. In this paper, we introduce the EMI technique, which the metal material is applied in shielding the strong electromagnetic wave interference on some frequency region in field space, and analyze the electromagnetic shielding principle of the metal plate and the metallic mesh. The design method and the actual manufacture about the shielding system are also given. The test result shows that the system’s shielding effectiveness is practical and effective.


2019 ◽  
Vol 16 (9) ◽  
Author(s):  
Chun Cheng ◽  
Zhonghua Du ◽  
Xi Chen ◽  
Chengxin Du ◽  
Lizhi Xu ◽  
...  

Author(s):  
Bridget Carragher ◽  
David A. Bluemke ◽  
Michael J. Potel ◽  
Robert Josephs

We have investigated the feasibility of restoring blurred electron micrographs. Two related problems have been considered; the restoration of images blurred as a result of relative motion between the specimen and the image plane, and the restoration of images which are rotationally blurred about an axis. Micrographs taken while the specimen is drifting result in images which are blurred in the direction of motion. An example of rotational blurring arises in micrographs of thin sections of helical particles viewed in cross section. The twist of the particle within the finite thickness of the section causes the image to appear rotationally blurred about the helical axis. As a result, structural details, particularly at large distances from the helical axis, will be obscured.


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