Metals are good conductors of electricity and can reflect or absorb electromagnetic waves, therefore a metallic enclosure, such as a case, chamber, or a cabinet is often used for EMC shielding. It effectively creates a barrier between the electronic equipment and the electromagnetic fields that could cause unwelcome interference.

A metallic enclosure fabricated from sheet metal such as aluminium, completely enclosing the electronic equipment, creates what is known as a Faraday cage. A Faraday cage is a metallic enclosure that can block external electromagnetic fields by creating a conductive surface that is able to reflect or absorb the electromagnetic waves. The Faraday cage can also reduce the electromagnetic radiation that is generated by the electronic equipment itself. It can therefore block EMI progressing inwards and outwards.

The design of a metallic enclosure and its effectiveness for EMC shielding depends on several factors, including the properties of the metallic material, the frequency and strength of the electromagnetic waves to be blocked, and the design and manufacturing of the enclosure. For example, a thicker and well-conductive sheet metal enclosure provides better EMI protection than a metal enclosure manufactured from a less-conductive material. Explore Ocotec’s RF/EMC/EMI engineering and manufacturing here.

In addition to providing protection against EMI, a metallic enclosure can also offer physical protection for the electronic equipment from environmental factors such as moisture, heat, dust, and physical impact. It can also be used to help contain electromagnetic radiation generated by the electronic equipment that it holds, thus preventing interference with other nearby equipment.