Without shielding, even the best-designed electronics are susceptible to electromagnetic noise. This is because electromagnetic disturbances affect the functionality and efficiency of every electronic device. Electromagnetic radiation is present all around us. The electronic devices produce waves and signals known as Electromagnetic interference (EMI) and radio frequency interference (RFI). These signals pose a serious risk to electronic devices if not controlled. And that’s where Faraday cages come in.
What is a Faraday cage?
Faraday cage is named after the English scientist Michael Faraday who invented it in 1836. In the present modern technological world, Faraday cages have become omnipresent. A Faraday Cage, also known as a Faraday Shield, is used as a protective shield against electromagnetic radiation. It protects the devices from EMI/RFI coming from the external environment, as well as prevents electromagnetic energy radiated from the internal components from escaping the cage. A Faraday Cage is an electronic isolation chamber or a container that restricts electrical signals or waves from passing through it. These cages may look like a chain-link fence or a fine metallic mesh.
How Does It Work?
A Faraday cage acts as a barrier between the internal components of a device and the external electromagnetic radiations. The cage is made of conductive material which distributes electrostatic charge around the device’s exterior. By blocking the ingress and egress of the electric charges, the Faraday shield ensures the proper functioning of the device without interruption. While designing an electronic device, a non-conductive insulator such as cardboard, plastic, glass, or wood is used inside the enclosure to separate internal components from the outer conductive skin.
Applications of Faraday Cage
Every appliance in your home – from the microwave oven and laptop to the refrigerator is vulnerable to electromagnetic waves. These electronic devices need protection from EMI to function properly. And this is where design engineers need to incorporate a Faraday shield into the devices.
To understand Faraday cage better, let’s take a look at some real-world examples of its applications. The most notable example of everyday uses of Faraday Cages is right inside your kitchen- Microwave. However, unlike other applications, the purpose of a Faraday shield in the microwave is different. The microwave oven uses radiation for reheating your food. To prevent that radiation from leaking, there is a mesh screen in the window of your microwave which is part of a Faraday cage. The metal shell in the microwave oven helps in keeping the radiation within the oven. Another interesting application of Faraday cages is automobiles and airplanes. The fuselages of aircraft and cars work as Faraday Cages for the passengers.
The MRI scan rooms also need faraday cages to block external radio frequency signals from causing interfering with the data coming from the patient. The military and other organizations also use Faraday cages to protect sensitive IT and other electrical equipment. Interestingly, this technique is also used in situations where eavesdropping devices need to be blocked. Politicians and other high-level executives often conduct meetings in specially shielded rooms to ensure secrecy.