Using Metal for EMI Shielding

Metal makes an excellent conductor of electricity, which means that it can reflect, absorb, and transmit electromagnetic interference. Different types of metal contain different electrical conductivity characteristics. For instance, (Conductivity [S/cm])Silver is 6.8 × 105  whereas Graphite is only 5.0 × 102. Plastic and rubber are both non-conducting, and as such, they are transparent to EMI. Another reason to use metal in EMI shielding is that of metal’s ability to conduct both heat and electricity. Because of its practicality, it is used in many applications. Applications include:

1. Electrical equipment (when high static charges are present)
2. High-speed machinery (especially when generating heat)

The two above applications are protected by being grounded by metal conductors, which dissipate heat and static charges. In addition to this, high-frequency electromagnetic radiation is shielded from stray radiation by metallic covers and shields.

The most commonly used construction is an alloy that is made of iron, copper, chromium, and nickel. Other widely used metals include brass, silver, aluminum, and stainless steel. For those that require shielding applications that are based on reflection, magnesium enclosures can extend over the entire frequency spectrum.

For more information on custom EMI shielding, give us a call to discuss your needs.

Related Reading

• Mounting a Shielding Gasket
• Understanding Oriented Wire Shielding and how it Works
• EMI use of Gaskets in Military
• The Science of Shielding
• Shielding Gaskets and Corrosion