What Is Electromagnetic Interference Shielding?
Electromagnetic interference shielding refers to materials used to reduce or prevent electromagnetic interference. This concept is called noise control or EMC measures. Materials used as electromagnetic interference shielding are also called shielding materials.
Electromagnetic waves are generated by various devices in our daily life.
Cellular phones communicate through built-in antennas and base stations by emitting electromagnetic waves called radio waves. They use radio waves in the frequency range of 800 gigahertz to 2 gigahertz, known as microwaves.
Since electromagnetic waves exist in various wavelengths, they are generated when a plug is plugged into an outlet.
The material used to control such electromagnetic waves so that they do not interfere with each other is electromagnetic interference shielding.
Principle of Electromagnetic Interference Shielding
Electromagnetic interference shielding generally reduces the effects of electromagnetic waves by reflecting them. For example, there are two types of electromagnetic interference shielding methods for plastics: surface treatment and combined methods.
Surface treatment methods include the application of conductive paint (silver, nickel, copper) or plating (copper, nickel, chrome), vacuum deposition, sputtering, ion plating, and metal spraying.
Composite methods include glass and carbon fibers, metal fibers, metal flakes, and powders, which are a mechanism to obtain electrical conductivity and shielding properties by mixing conductive fillers with plastics.
In addition to reflecting electromagnetic waves, electromagnetic interference shielding can also be used to prevent electromagnetic waves by absorbing them. The methods are explained below.
How to Choose Electromagnetic Interference Shielding
What you need to know in selecting electromagnetic interference shielding are the composition and properties of electromagnetic waves.
Electromagnetic waves are broadly classified into radiation, light, radio waves, and electromagnetic fields, and are further divided into smaller categories.
For example, radiation is subdivided into gamma rays and X-rays. The frequencies and wavelengths of each are different and must be taken into consideration when selecting electromagnetic interference shielding.
From here, we will explain the less familiar electromagnetic field listed above.
Other Information on Electromagnetic Interference Shielding
1. How to Use Electromagnetic Interference Shielding
There are two types of electromagnetic interference shielding: electromagnetic shielding and magnetic shielding. Each is explained below.
Electromagnetic shielding: Prevents the intrusion or leakage of radio waves by enclosing the target space with conductive materials.
Magnetic Shield: Uses magnetic materials such as iron to seal the space, thereby bypassing magnetism and preventing its intrusion.
2. Absorption of Electromagnetic Waves
Electromagnetic interference shielding can absorb electromagnetic waves by allowing them to pass through their interior, thereby attenuating the energy of the electromagnetic waves.
3. Effectiveness of Electromagnetic Interference Shielding
Electromagnetic interference shielding is evaluated quantitatively using a numerical value called SE (Shielding Effectiveness).
4. About Electromagnetic Fields
Electromagnetic fields exist in power lines and household appliances. The term “electromagnetic field” refers to a phenomenon that combines electric and magnetic fields.