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The Importance of RF Interference Shielding

Published Date
Author Cadence PCB Solutions

Key Takeaways

  • RF interference shields are enclosures made of metal that completely enclose the sensitive circuit inside. 

  • RF interference shielding is designed for military communication and other electronic systems to prevent data leakage. 

  • There are different classifications for RF interference shielding in electronics.

 Medical devices

Stringent RF interference shielding is employed in medical devices to prevent malfunctioning due to RF noises

The application of electronic devices in automotive, aerospace, aviation, medical, and engineering industries makes them vulnerable to electromagnetic interference. Electromagnetic interference is the phenomenon in which unintended electromagnetic waves disturb the functioning of devices utilizing electromagnetic energy. Electromagnetic interference created by radio waves is called radio frequency interference (RFI).

It is important to protect electronic devices from RFI to ensure their smooth operation. RF interference shielding is one method that can be used to eliminate RF interference from disrupting the proper functioning of electronic devices. Let's focus on RF interference shielding in this article. 

RF Interference

Electromagnetic interference (EMI) is any unwanted signal that is injected into an electronic circuit from a source and disturbs the normal working of the circuit (victim). An electronic circuit is a victim of EMI when its workings are affected by EMI. The same circuit can act as a source, thereby disrupting the operation of nearby devices and equipment.

The coupling of EMI from source to victim occurs in different ways. The way by which EMI travels from source to victim can be described by the EMI coupling mechanism. The coupling path differs in each EMI coupling mechanism, and it is important to understand EMI traveling routes and ways for addressing mitigation methods.

When the source and victim are separated physically from each other, EMI travels via air or vacuum to reach the victim. The electromagnetic interference is radiated in this type of EMI coupling and causes radio frequency interference (RFI). RFI is most often caused by higher-frequency signals in the radio frequency or microwave frequency range.

RFI is the most commonly experienced form of EMI. As there is no physical connection required for RFI, it is likely to affect most electronic circuits. The estimation of RFI in electronic circuits is important, as it ensures electromagnetic compatibility (EMC).

Fortunately, there are ways to mitigate RFI, including RF shielding. 

RF Interference Shielding

RF shielding is a method to protect electronics from RFI. RF shielding also prevents devices from radiating emissions. RF shielding protects devices from the exposure of unintended radiofrequency waves or electromagnetic waves. RF interference shields are enclosures made of metal that completely enclose the sensitive circuit inside. A Faraday’s cage is an example of an RFI shield used in electronic circuits. RF shielding materials either absorb or reflect EMI radiations, ensuring devices are immune to RFI.

Depending on the RFI that needs to be mitigated, material properties such as permeability and conductivity of the enclosure change. The shape and thickness of the metal shield are also influenced by the type of circuit and its emissions. The design of the RF interference shield is critical due to the growing market for electronic devices and the disproportionately high monetary losses caused by RFI. 

The Demand for RF Interference Shielding

As consumer products, automobiles, and home appliances incorporate built-in electronics and smart features, the demand for custom-made RF interference shielding increases. The following systems use custom-made RF interference shields for protection against RF interference.

5G networks: 5G technology is vulnerable to EMI, especially RFI, as most of these networks depend on millimeter waves. The expansion of 5G networks is expected to follow EMC regulations. RF interference shielding is employed in order to achieve electromagnetic immunity.

Automotive industry: The development of autonomous and semi-autonomous vehicles introduced numerous electronic components and sensors into vehicle architecture. The response of these electrical and electronics systems are important for the safe operation of the vehicle. Automotive networking uses ethernet communication protocols for setting up data transfers with a central computer system. Non-metallic body components like panels or bumpers are also vulnerable to external RF noises. RF interference shielding techniques are used in automobiles to ensure the smooth operation of electronic systems.

Medical equipment: The principles of electromagnetics are utilized by sophisticated medical equipment and devices. Any glitch caused by interference can potentially cause a loss of human life. Stringent RF interference shielding is employed in medical devices to prevent their malfunctioning due to RF noises.

Military systems: The data from military systems are mission-critical and vulnerability to RF interference can make the data vulnerable to hackers. RF interference shielding can be specifically designed for military communication applications and for other electronic systems to prevent data leakage. And, for reliable and safe operation, military vehicles are also shielded from EMI and RFI.

There are different classifications for RF interference shielding in electronics, such as component shielding, board shielding, and cable shielding. Cadence’s suite of design and analysis tools can assist you in planning an appropriate RF interference shielding technique. Subscribe to our newsletter for the latest updates. If you’re looking to learn more about how Cadence has the solution for you, talk to our team of experts.