Speaking of shielded rooms, perhaps everyone is not unfamiliar. A shielded room can block the diffusion of indoor electromagnetic radiation to the outside world, and strong electromagnetic radiation sources should be shielded and isolated. The shielding room is made of magnetic materials. The parameter to measure the magnetic permeability of the material is permeability. The higher the permeability, the better the shielding effect. There are many materials in the construction of shielded rooms, such as microwave absorbing materials and shielding materials. What is the difference between absorbing materials and shielding materials?
1. Absorbing materials
Absorbing material refers to a type of material that can absorb the electromagnetic wave energy projected on its surface. It converts incident electromagnetic waves into heat or other forms of energy through various loss mechanisms of materials to achieve the purpose of absorbing electromagnetic waves. In engineering applications, in addition to requiring a high absorption rate of electromagnetic waves in a wide frequency band, the absorbing material is also required to have light weight, temperature resistance, humidity resistance, and corrosion resistance. The absorbing effect of the absorbing material is determined by various electromagnetic mechanisms inside the medium, such as Debye relaxation of the dielectric, resonance absorption, interface relaxation, resonance relaxation of the magnetic medium domain wall, electron diffusion, and micro-eddy currents.
2. Shielding material
Shielding material is a type of material that can isolate the metal between two spatial regions to control the induction and radiation of electric fields, magnetic fields and electromagnetic waves from one region to another. Specifically, it is the material used to make the shield. The shielding body surrounds the interference sources of the components, circuits, assemblies, cables or the entire system to prevent the interference electromagnetic field from spreading out; the shielding body surrounds the receiving circuit, equipment or system to prevent them from being affected by the external electromagnetic field.
3. The difference between absorbing materials and shielding materials
The electromagnetic wave of the absorbing material cannot go in and out, but the electromagnetic shielding material does not necessarily reflect the electromagnetic wave, but reduces the amount of electromagnetic wave reaching the other side of the shielding material through either absorption or reflection. Therefore, it can be said that the absorbing material is to make the same side of the absorbing material and the electromagnetic wave emitting source receive as little as possible the reflected electromagnetic waves, and the electromagnetic shielding material is to shield the material and the electromagnetic wave emitting source to receive as little as possible on the opposite side. The influence of electromagnetic waves.
The difference between the above-mentioned absorbing materials and shielding materials is shared here. The absorbing materials and shielding materials in the shielding room effectively shield power sources, relays, transformers, motors, CRTs and other low-frequency magnetic field interference sources or sensitive equipment. The correct use of different types of shielded rooms is also a reliable measure to prevent information from leaking with electromagnetic waves.