As different places have different requirements for shielding, in order to meet people's different shielding needs, the level of shielding technology is gradually improving. Since the shielding materials are different in the use of shielded computer rooms, people have also raised questions about whether the shielding effect of the shielded computer rooms is related to the shielding materials. So what situation will affect the effect of the shielding material? The following is introduced by the editor:
1) The better the conductivity and magnetic permeability of the material, the higher the shielding effectiveness, but the actual metal material cannot take into account these two aspects. For example, the conductivity of copper is very good, but the magnetic permeability is very poor; the magnetic permeability of iron is very good. , But the conductivity is poor. What material should be used, depending on whether the specific shielding mainly depends on reflection loss or absorption loss to determine whether to focus on conductivity or magnetic permeability;
2) Electric field waves are the easiest to shield, followed by plane waves, and magnetic field waves are the most difficult to shield. Especially the low frequency magnetic field (below 1KHz) is difficult to shield. For low-frequency magnetic fields, high-permeability materials should be used for shielding. Several conditions affect the effectiveness of the shielding materials and even use a combination of high-conductivity materials and high-permeability materials.
3) When the frequency is low, the absorption loss is very small, and the reflection loss is the main mechanism of the shielding effectiveness. The reflection loss should be increased as much as possible;
4) The reflection loss is related to the distance between the shield and the radiation source. For electric field radiation sources, the closer the distance is, the greater the reflection loss; for magnetic field radiation sources, the closer the distance is, the smaller the reflection loss; correctly judge the nature of the radiation source It is an important content of structural design to decide whether it should be close to the shield or the principle shield.
5) At higher frequencies, absorption loss is the main shielding mechanism, and at this time it has little to do with whether the radiation source is an electric field or a magnetic field.
6) The reflection loss is related to the characteristics of the radiation source. For the electric field radiation source, the reflection loss is very large; for the magnetic field radiation source, the reflection loss is very small. Therefore, the shielding of the magnetic field radiation source mainly depends on the absorption loss of the material, and the material with higher magnetic permeability should be selected as the shielding material.