Electromagnetic interference (EMI), also called radio-frequency interference (RFI) when in the radio frequency spectrum, is a disturbance generated by an external source that affects an electrical circuit by electromagnetic induction, electrostatic coupling, or conduction.
EMI Shielding in electronic devices and equipment is the use of manufacturing techniques and materials to protect signals from being disrupted by external electromagnetic signals as well as preventing generated signals from interfering with surrounding components.
Traditionally, EMI shielding has been fabricated from metal sheets and formed into shapes that fit electronic housings or enclosures: Aluminum, copper, and steel are strong and rigid.
Today, EMI shielding materials include flexible metal screens, metal wires, metal foams and conductive silicones. Coatings made of metallic inks are also applied to the interiors of electronic enclosures to provide EMI shielding solution. Each of these shielding methods has its advantages.