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EMI - RFI Shielding

EMI - RFI Shielding

The electronic world is a classic example of 'the good, the bad and the ugly'! Well, as much as we cannot deny that the media has enhanced our very lifestyles, it has also exposed us to electromagnetism that takes it toll on us.
Gaynor Borade
Nowadays, there is hardly any commercial undertaking that does not involve the demand for electromagnetic interference (EMI) input into the business. With every additional electronic device put in place, there is an increase in the desired and conditioned frequencies as well. This has made it mandatory to address the need for effective shielding from radiation and immunity from an early stage, during the development of new products. There are times when the electromagnetic interference shielding cannot be taken care of, without creating enclosures for the cables that have to be shielded.

EMI - RFI shielding is a fast and efficient way to comply with legal demands, in the case of businesses that need to critically prevent electro-magnetic interference. The methods used today for effective shielding are not time-consuming and the development is very cost-effective. This makes it lucrative to adopt the strategy, especially in the case of non consumer product quantities, that are designed for quick market introduction. EMI - RFI shielding is also used in the case of appliances with high radiation or sensitivity levels.

How are Radiation and Conduction Implemented

EMI - RFI shielding enables electro-magnetic interference to be transferred by radiation and conduction. The program and plan of conduction is effective in frequencies below 10 MHz. To implement conduction, it is necessary to ensure that all the cables and enclosures are shielded or protected with materials that are magnetically conductive. It is important to note that the lower the frequency, the thicker the shielding needs to be. In the case of cable shielding solutions for high frequencies of over 40 MHz, a very thin layer of highly conductive material is used.

The 'Gap' Consideration

When addressing the need for effective EMI - RFI shielding, it is essential to note that the higher the frequency, the shorter will be the wavelength. So when the frequency increases, the tolerable gap dimension decreases. This calls for extensive electric connectivity in doors and panels, from all sides, with the help of the EMI shielding gaskets. The gaskets are self-adhesive and easy to mount. The selection of the appropriate gasket is determined on the basis of the rigidity of the construction, the set distance between the fixtures and the construction materials used. If the gasket is very tense or rigid, then the panel will deflect and gaps will be caused.

There are several kinds of gaskets that have been developed. They combine the versatility of large compression range, low closure force, and high conductivity. The available gasket options for EMI - RFI shielding can be used without changing the existent construction. The prescribed stiffness of the gasket needs to be adhered to for optimum effect. You have to ensure that the fixtures adopted are galvanically compatible with the other construction materials already in place, to prevent corrosion of the contact surfaces. The gaskets with a conductive layer of reinforced materials, like zinc-plated steel and aluminum, effectively prevent any kind of corrosion.

EMI - RFI Shielding Tips
  • It is absolutely safe to consider low light transmission coefficients, even a mesh shield.
  • When adopting shielding at construction level, consider small, rectangular windows, since the distance from the center of the window to the edge is smaller.
  • Always seek options armed with the correct size needed, in mm, and specifications, on the free viewing area.
  • It is necessary to specify quantities and sizes rather than vague square meters.
  • Consider window water seals on the inside or outside of the window.
  • It has become imperative to address the right shielding option, and the construction level of a private or commercial property is the best time to adopt any one.