Magnetic shielding, also called electromagnetic (EMI) shielding, is the process of protecting electronic equipment from ambient electromagnetic interference that can cause electronic components to malfunction. Electromagnetic interference is the magnetic field which is created by electrical currents and can be caused either intentionally or unintentionally, which is far more common.
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Magnetic Shielding
EMI can travel along wires, electrical circuits and conductors, while radio frequency interference (RFI) is radiated electromagnetic "noise" which travels through the air as radio waves. Both EMI and RFI cause interruption and interference of electrical flow in sensitive electronics devices such as mobile phones, laptops, computers, monitors and many others. However, most problematic EMI comes from electromagnetic cross-talk between different components on the same board as EMI travels across wires and conductive materials. Magnetic interference can be blocked through two main methods: physical objects such as EMI enclosures or un-apparent objects such as EMI coating or transmitted signals. Of the two types of magnetic shielding products, physical objects are more commonly used as magnetic shielding and RFI shielding to guard sensitive electronic equipment; magnetic shielding is essential in many industries dependent upon electronic equipment, such as sound, lighting, industrial, medical, defense and telecommunications industries.The most common methods of magnetic shielding protection are through the various are EMI enclosures, EMI coatings, EMI gaskets and EMI filters. EMI enclosures, or "faraday cages" provide magnetic shielding for electronic equipment by absorbing harmful magnetic signals and radio waves. EMI enclosures are generally constructed from aluminum, stainless steel, nickel or copper alloys. EMI coating allows for more flexible applications, as it may be spray-coated to the inside of plastic housings or the outsides of wires and regular enclosures. "Metal inks" containing copper, nickel or chromium alloys may be sprayed on to virtually any housing or material to create the effect of EMI shielding. EMI gaskets create more robust EMI and RFI protection by preventing the leakage of EMI in or out of an enclosure through seams or gaps. Gaskets are made from electrically conductive rubber materials and are often combined with EMI shielding metals. An alternative to enclosures, coatings and gaskets is the EMI filter, a passive electronic device which blocks high EMI frequencies, allowing normal low frequencies to pass. EMI filters are used to block electromagnetic interference which is conducted through power lines and signals, and do not provide magnetic shielding for air-transmitted magnetic radio frequency interference.
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Magnetic Shielding Images Provided by INTERMARK (USA), INC.
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