What is EMI Shielding and how does it work?

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What is EMI Shielding and how does it work?

EMI Shielding is a way of protecting electronic equipment and machinery from harmful electromagnetic radiations that may disrupt the proper working and functioning of the instrument. It protects the signals from outer radiations while also protecting the inside radiations from leaking. EMI Shielding can cover sensitive components, wires, and cables. EMI or EMC is short for electromagnetic compatibility which means that a circuit when shielded makes it resistant to any waves that may disrupt its smooth functioning.

How does EMI Shielding work?

We are constantly surrounded by electromagnetic radiation. They are invisible but do cause heating and burning effects. The primary function of an EMI shield is to protect sensitive devices from radio and electromagnetic interferences. The device is made to use a metallic shield that absorbs the radiation that our presence in the air. What this screen does is that it absorbs the hear or emissions produced by the radiation and causes a current in the screen of the shield. This current is directed towards the earth or a virtual ground connection thus safeguarding the electronic device. The metallic shield maximizes the effectiveness of the protection since the entire circuit is protected due to the current running underground.

How is EMI Shielding done the best?

There are certain designated substances and materials that are proven to effectively shield electronic devices against any harm. The material used depends upon the nature of the electronic device and the frequency of the rays that it is most exposed to. The three factors that affect the range and strength of target frequencies are:

  • The material used is the shielding.
  • Material thickness
  • Size of the shielded volume

The different types of materials used for shielding electronic equipment are:

  • Coaxial cables have a built-in EMI shield under the insulation layer in the wire construction. The ends of the wire have connectors that require metal shielding and the braiding or foiling needs to be attached to it to give complete protection.
  • In speakers, an inbuilt audio metallic case protects the device from radiation from microwaves, refrigerators, and televisions.
  • Mesh metal screening and conductive plastics are used for providing insulation and protection. Conductive paints are used where the target frequency is less than 100KHz.

Combinations of EMI Shielding

EMI shielding has a broad range of applications. Almost all devices use EMI shielding because this gives the device a longer life. It not only promotes unhindered working but also keeps a check on the durability of the electronic equipment.

  • EMIs are used in medical facilities in pacemakers to keep the outer and inner radiation segregated. Any interference may directly impact the health of the patient.
  • As we know how valuable privacy is, EMIs installed on data chips prevent data theft.
  • For military security and government organization, EMIs help in sending encrypted messages which promote secret communication. These are installed with air-gape security cameras that further protect the privacy of security cameras and other surveillance devices.
  • Even in simple computers, hard drives, disks, motherboards, an EMI is considered to protect these gadgets from any heating due to outer radiation.

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