How to Stop Radio Frequency (RF) Interference

Radio frequency (RF) interference can affect your electronic device’s performance, causing inaccurate readings or, in some cases, stopping your device from functioning. 

All major markets have regulations that apply to RF interference. These regulations set clear limits for radio frequency immunity (your device’s ability to tolerate RF waves) and emissions (radio frequency waves released from your device).

In the guide below, you can learn more about what radio frequency interference is, how it can occur, as well as techniques that you can use to ensure your device complies with all relevant standards for RF emissions and immunity.

We offer a range of services to help you improve your device’s electromagnetic compatibility and achieve compliance with regulatory standards such as FCC Part 15, Canada ISED, and European regulations such as the EMC Directive and Radio Frequency Directive (RED).

To request a quote for testing your device, ask our engineers a question, or inquire about our EMC consulting services, contact us online or call us at 866-540-5287. 

What is Radio Frequency Interference?

Radio frequency interference is a form of electromagnetic interference (EMI) caused by energy in the radio frequency spectrum. Radio waves emitted from a device may interfere with devices in the surrounding area, which can cause performance issues.

If your device produces radio frequency emissions outside the limits set by regulations such as FCC Part 15, it may cause radio frequency interference that affects other devices.

Alternatively, if your device does not have sufficient electromagnetic immunity due to its design or components, its performance may also be affected by radio frequency emissions from other devices. 

Electromagnetic compatibility (EMC) regulations and international standards set limits for radio frequency emissions, as well as minimum requirements for radio frequency immunity.

Causes of Radio Frequency Interference

Radio frequency interference occurs when radio waves affect the functioning, accuracy and/or performance of a separate device.

There are numerous sources of radio frequency emissions. Some sources are natural, such as lightning, solar storms and cosmic noise. However, most radio frequency emissions are emitted from devices that produce radio frequency waves, either intentionally or unintentionally.

Devices that use the radio frequency spectrum for communications are referred to as intentional radiators. These devices, which include smartphones and Wi-Fi equipment, use radio frequency waves as part of their normal operations.

Devices that do not deliberately emit radio frequency energy, but may do so as an unintentional byproduct of their design, are referred to as unintentional radiators. 

Radio frequency emissions from these devices may affect other electronic devices, resulting in radio frequency interference. 

How to Reduce & Stop RF Interference

EMI Shielding

Shielding involves the creation of a shield around parts of your device sensitive to RF emissions using materials that either absorb or reflect electromagnetic waves. The idea behind shielding is to create a barrier that stops radio frequency energy from affecting your device.

Common EMI shielding materials include pre-tin plated steel, aluminum, copper and others. For certain devices, film, tape and foil materials, or silicone shielding, may be molded into shapes to provide both EMI and environmental shielding. 

Our guide to EMI shielding materials provides more information about how shielding is used for reducing RF emissions and interference. 

EMI Filtering

Filtering involves the use of active or passive filters to absorb excess energy within an electrical circuit and reduce electromagnetic emissions. Filters work by creating an opposite current flow, or by reducing emissions within specific frequencies.

Used effectively, filters can reduce electromagnetic emissions from your device and increase its immunity to radio frequency interference caused by external emissions.

Many devices use EMI filtering alongside other techniques to improve electromagnetic immunity and performance. 

PCB Design

Certain printed circuit board design techniques, such as locating high-speed components away from the edges of your devic’s circuit board and reducing loop area, can reduce emissions and improve your device’s radio frequency performance.

Grounding

Proper grounding techniques provide a safe path to the ground for electricity, which can reduce your device’s electromagnetic emissions. Grounding is typically used in combination with other techniques to reduce radio frequency interference and issues such as conducted emissions. 

Other Techniques

Other techniques for reducing radio frequency interference include:

• Software changes, which may adjust the frequency of processors in your device and limit its electromagnetic emissions.
• Cable and connector management to control your device’s cable loop area and lower emissions and interference.
• Spread spectrum clocking and other methods to spread your device’s emissions over wider frequency ranges and improve its electromagnetic compatibility.

Our guide to reducing electromagnetic interference provides more information about common techniques used to lower emissions and improve electromagnetic compatibility. 

Contact Us About EMC Testing & Certification

Reducing your device’s radio frequency emissions and improving its immunity to RF emissions from other devices is a key part of electromagnetic compatibility.

Many regulations, including FCC Part 15, require that your device complies with standards for radio frequency immunity. Your device’s performance is verified in lab testing, which is legally required for equipment authorization from the FCC.

As an ANSI-accredited electronics testing lab and FCC-recognized TCB, we can help you to achieve compliance with FCC Part 15, the European Union’s EMC Directive, and other EMC standards and regulations.

To request a free quote for your device, or to talk to our engineers about the testing and FCC certification process, contact us online or call us at 866-540-5287.