Any electronic device can be affected by electromagnetic interference (EMI). Most devices have built-in EMI shielding to minimize the effects of these disturbances. For example, smartphones and tablets have shielding to protect chips and interfaces for cellular, Wi-Fi, and other radio frequency signals.
However, such internal shielding isn’t foolproof, and highly sensitive equipment may need further protection when there’s a significant source of EMI. For example, electrical cords are very efficient at transferring EMI into the surrounding environment and can cause network performance problems and other issues if not properly managed.
What Is a Faraday Cage?
Electronic devices can be protected from EMI using a Faraday cage — an enclosure that uses a conductive material to attenuate undesirable electromagnetic frequencies. Microwave ovens are commonplace examples of Faraday cages. The shielding on network cables is also based on Faraday cage principles.
History of the Faraday Cage
The Faraday cage was invented in 1836 by English scientist Michael Faraday, who discovered that an electrical conductor could be used to block electromagnetic fields. He observed that a charge was present only on the conductor’s surface and did not affect its interior.
He demonstrated the effect by building a room shrouded in metal foil and bombarding it with high-voltage electrostatic discharges. An electroscope inside the room showed that no electric charge was present. The charge remained on the foil’s surface and never penetrated the shielding to enter the room.
What Is a Faraday Cage Used For?
Faraday cages have several applications in IT. They can shield sensitive equipment from electrical disturbances and prevent side-channel attacks in which hackers intercept and analyze electromagnetic emissions. They are also used to minimize radio frequency (RF) interference when testing electronic devices.
How to Construct a Faraday Cage
You can buy EMI shielding materials online to construct a Faraday cage, but there are several factors to consider.
Faraday Cage Materials
A variety of materials can be used, including copper, aluminum, and steel. However, the effectiveness of the shielding depends upon the electrical conductivity and magnetic properties of the material. For example, copper is expensive but doesn’t need to be as thick as other materials to attenuate RF signals.
Application Considerations
If a wide range of electromagnetic interference must be blocked, the enclosure may need to be wrapped in multiple layers of conductive material. Any holes in the enclosure must be significantly smaller than the wavelength of the radiation.
You can also buy ready-made Faraday cages, including bags and pouches for smartphones, tablets and laptops, and enclosures for wireless routers. However, such consumer-grade products have little to no value in the enterprise IT environment.
Faraday Cages in the Data Center
Shielded cabinets provide the best protection against EMI in the data center. Historically, shielded cabinets were primarily used as a cybersecurity countermeasure against power analysis and EMI side-channel attacks. The proliferation of Wi-Fi, Bluetooth, and other wireless technologies pose additional eavesdropping threats, increasing the need for Faraday cages that attenuate a wide range of radio frequencies.
Real device testing is another significant use case of shielded cabinets. Organizations that need to test applications on smartphones, tablets, IoT devices, and other hardware need a means of attenuating RF interference. A rack-level Faraday cage is the ideal solution.
Enconnex Shielded Cabinets
Enconnex partners with best-in-class, government-approved manufacturers to deliver high-performance RF/EMI-shielded enclosure solutions. Designed to achieve significant signal attenuation across wide frequency ranges, these enclosures are available in both standard cabinet and wall-mounted configurations. They combine a compact, lightweight footprint with UL-listed construction, integrated thermal management, and flexible customization to meet the unique demands of each deployment. Connect with our team to explore how we can support your RF/EMI shielding requirements with proven, scalable solutions.
Contact Enconnex today to learn more.