If you’re developing an electronic device, one of the most important steps in bringing it onto the market is ensuring that it complies with electromagnetic compatibility (EMC) regulations like the Code of Federal Regulations, Title 47, Part 15, also referred to as the FCC Part 15 rules.
FCC Part 15 and similar regulations set limits for electromagnetic interference, or EMI. Devices that cause interference, or are susceptible to interference from other electronic devices, usually need to make changes to improve EMC performance and pass lab testing.
One of the most common ways to reduce interference caused by your device is through the use of EMC shielding.
Below, we’ve explained what EMC shielding is, as well as how shielding techniques can work to reduce your device’s emissions and improve compliance with the FCC rules.
For more information about EMC compliance, or to request a free quote for testing your device and achieving compliance with FCC Part 15 or similar regulations, contact us online or call our team at 866-540-5287.
What is EMC Shielding?
The term EMC shielding refers to a variety of methods used to protect electronic devices from electromagnetic interference (EMI).
Electromagnetic interference is unwanted, undesirable noise in an electrical circuit that’s linked to an external source. Any device that generates electromagnetic energy can potentially cause interference when it shares an environment with other electronic equipment.
EMI can cause a range of performance issues in electronic devices, including loss of signal or inaccurate readings. In industrial and medical settings, electromagnetic interference can result in safety issues when electronic devices fail to function properly.
Our guide to electromagnetic interference goes into more detail about how EMI occurs, as well as the effects it can have on electronic devices.
Shielding involves using enclosures, coatings, foil shielding and other approaches to stop your device from producing electromagnetic emissions. It also protects your device from emissions from other devices, which helps to improve its immunity and electromagnetic compatibility.
Because shielding reduces radiated emissions and improves your device’s level of protection against interference, it’s usually important for achieving compliance with EMC regulations.
Common EMC regulations include FCC Part 15, as well as European regulations such as the European Union’s Electromagnetic Compatibility (EMC) Directive and Radio Equipment (RED) Directive.
How Does EMC Shielding Work?
The primary purpose of shielding is to reduce electromagnetic emissions from a device, and to shield the device from electromagnetic emissions from other electronic equipment.
EMC shielding works by either reflecting or absorbing electromagnetic waves. For example, a common method of shielding is to use a shield can, or metallic shielding enclosure, to prevent electromagnetic energy from affecting a device.
Shielding works on the principle of the Faraday cage — a type of enclosure that blocks access for electromagnetic fields.
In this way, shielding functions like a barrier, or physical shield, that stops emissions from your device’s internal components from spreading outside the device, and stops emissions from the surrounding environment from entering into your device.
You can think of shielding as working similarly to insulation in your home. Much like insulation keeps the heat in during the winter and out during the summer, EMC shielding keeps electrical “noise” where it belongs, be it inside your device or outside its shielding.
Common Types of EMC Shielding
There are several different types of EMC shielding, each suited to different environments and applications.
Common types of EMC shielding include:
- Metal shielding. Metal enclosures are among the most effective methods of shielding, providing strong protection against EMI. Enclosures used for EMC shielding are called “shield cans” and are often used to protect sensitive components from EMI.
- Conductive coatings. Conductive paints and coatings are usually applied to non-metal surfaces, such as plastic casings. These coatings contain materials such as copper and nickel to provide electromagnetic shielding properties.
- Gaskets and seals. Gaskets and seals are used to close gaps in electrical enclosures where EMI can potentially enter or exit. These are made from conductive materials and provide a continuous conductive path around the enclosure to reduce interference.
- Shielded cables. Cables can act as antennas, meaning they may potentially pick up or emit EMI. Shielded cables use a conductive layer to block unwanted signals and reduce electromagnetic interference.
- Shielding films and foils. Shielding films and foils are thin, flexible materials that can be applied to surfaces for EMC shielding. These are typically used to provide shielding for irregular shapes, or when metal enclosures can’t fit inside a device.
EMC Shielding Materials
A variety of materials are used for EMC shielding, including metals, conductive coatings and/or paints, fabrics and tapes. These materials are selected for their ability to either reflect or absorb electromagnetic radiation.
Most of the time, EMC shielding involves the use of metal materials. Several metals offer good electrical conductivity, making them ideal for improving electromagnetic compatibility.
Metals commonly used for EMC shielding include:
- Aluminum. Aluminum is lightweight and cost-effective, making it a widely-used metal in consumer electronics, telecommunications devices and other electrical equipment.
- Copper. Copper offers excellent electrical conductivity and is highly effective at shielding electric and magnetic fields. It’s often used for medical devices and other equipment that requires a high degree of electromagnetic compatibility.
- Steel. Steel, especially stainless steel, is often used as an EMC shielding material for its durability and effectiveness in protecting against magnetic fields. It’s often used to shield industrial equipment from electromagnetic interference.
- Nickel. Nickel is often applied to other surfaces as a coating to function as an additional layer of shielding against EMI. This material is commonly used when a solid metal shield is impractical or impossible to fit to a device.
Contact Us About EMC Testing & Compliance
Shielding is one of several methods used to reduce electromagnetic interference and help your device comply with electromagnetic compatibility regulations.
If you’re developing an electronic device and need to verify it’s compliant with EMC regulations such as FCC Part 15, the European Union’s EMC Directive, or others, our experienced team is here to help.
As an ANSI-accredited electronics testing lab, we can test your device and help you gain FCC and other compliance marks, allowing you to enter the market.
To request a free quote for your device, or to ask our engineers and compliance specialists any questions you have about EMC shielding, testing and regulatory compliance, contact us online or call us at 866-540-5287.
