Electromagnetic Shielding
With the rapid development of electronic technology, there are more and more electronic products and devices. Computers and other radio transmitting devices will generate electromagnetic waves of different wavelengths and frequencies, and electromagnetic pollution will follow. So how to solve the problem of electromagnetic pollution, the main method is to use electromagnetic shielding materials.
Electromagnetic shielding is to use electromagnetic shielding materials such as metal to make a shielding body, enclose the area that needs to be protected, and isolate the electromagnetic pulse outside the shielding body.
When an electromagnetic pulse comes, its electromagnetic energy is reflected, absorbed or blocked by the shield. Even if the electromagnetic pulse can penetrate the shield, the electromagnetic energy and electromagnetic field strength will be attenuated to an acceptable level.
This is one of the important measures to avoid electromagnetic interference of electronic equipment and electronic systems, and it can effectively reduce the electromagnetic interference leaked by space propagation. It can not only reduce the electromagnetic interference radiated from the electronic equipment, but also prevent the influence of the external electromagnetic interference on the electronic equipment.
Electromagnetic shielding can be divided into three categories according to the shielding principle
1. Electric field shielding
Mainly to prevent capacitive coupling between electronic components or equipment, it uses a metal shielding layer to encapsulate electronic devices or equipment, and its shield is made of good conductors and has a good grounding, so that the electric field stops on the surface of the conductor and passes through the ground. Induced charges in wires and on conductor surfaces, preventing mutual interference caused by electrostatic coupling.
2. Magnetic field shielding
By enclosing the magnetic lines of force in the shielding body, it prevents the internal magnetic field from diffusing outward or the external magnetic field interference from entering, and provides a low magnetic resistance path for the magnetic field inside and outside the shielding body to divert the magnetic field. Magnetic field shielding can well suppress interference caused by magnetic field coupling between noise sources and sensitive equipment.
3. Electromagnetic shielding
It is mainly used to prevent electromagnetic induction at high frequencies, and uses the reflection of electromagnetic waves on the conductor surface and the sharp attenuation of propagation in the conductor to isolate the mutual coupling of variable electromagnetic fields, thereby preventing the interference of high-frequency electromagnetic fields.
The most common electromagnetic shielding materials on the market
Surface conductive shielding materials, filled composite electromagnetic shielding materials, intrinsically conductive polymers, conductive fabrics, transparent conductive films, etc.
With the continuous development of science and technology, researchers will develop more and higher performance electromagnetic shielding materials to benefit mankind and society.
This article is comprehensively compiled from the popular science department of Xinhuanet, Science Popularization China-Scientific Principles Made Easy
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Cheersonic is the leading developer and manufacturer of ultrasonic coating systems for applying precise, thin film coatings to protect, strengthen or smooth surfaces on parts and components for the microelectronics/electronics, alternative energy, medical and industrial markets, including specialized glass applications in construction and automotive.
