A Quick and Informative Guide to EMI Shielding and Sources

BY ALT Technologies | 28th March 2022

Have you ever listened to the radio when the reception suddenly cuts out, only to start up again? Someone’s cell phone rang in your area, be it in your home, across the street, or in town, and it took over the radio signal temporarily. These are instances of electromagnetic interference (EMI).

EMI is a disruption of signal sources. It usually happens when one device’s signal crosses paths with another and mistakenly grabs the wrong one. Most people think that EMIs only affect radio and mobile phone communications. 

However, EMIs affect many devices, from radios and mobile phones to atmospheric and healthcare devices. This article will discuss EMI sources and shielding to understand EMIs and their impacts better. 

What Are the Sources of EMI?

Many things can cause electromagnetic disruptions on devices. But all these sources fall under two categories: natural and manufactured. 

Natural Sources

Although EMI affects manufactured devices, EMI can come from natural sources. Some of these sources include:

  • Cosmic noises
  • Electrical storms
  • Rain sprays
  • Solar flares and radiation
  • Storms.

Man-Made Sources

As the name implies, man-made devices can interfere with the communication of another device. This typically happens when machines are close to one another. 

Some devices that can cause EMI includes:

  • Devices that create stray magnetic fields
  • Equipment that produces significant signals
  • Heavy machinery
  • HVAC systems
  •  Loud equipment
  • Machinery that has stray electrical fields
  • Moving equipment
  • Radios
  • Telecommunication devices.


How Does Electromagnetic Shielding Work?

EMI shields are metallic screens that absorb EMIs. They typically surround your device’s sensitive or transmitting electronics. These device screens will provide solid protection against EMIs.

Your device transforms the signals it receives as electric currents. The shield will absorb the current when your EMI-shielded device receives these signals. This current will be transmitted to either a virtual ground plane or a ground connection, absorbing the current from the shield. 

This entire process ensures that your device receives and utilises clean signals every time.

What Are the Benefits of EMI Shielding?

The main benefit of EMI shielding is to protect device transmitters and sensitive components. But as EMI shields do this task, they also produce the advantages below:

  • Ensures clear AM/FM emergency service transmissions
  • Keeps pacemakers functional and functioning well 
  • Protects medical equipment
  • Prevents RFID data security breaches
  • Stops eavesdropping in government and military facilities
  • Thwarts eavesdropping attempts on financial institutions.

What Are the Available EMI Shield Options?

Aluminium, copper, and steel are the primary electromagnetic interference shielding materials. However, there is no one-size-fits-all solution for shielding. That is why engineers use various materials, shapes, and thicknesses to create the best EMI shielding solution for different devices. 

Some of the most popular EMI shield solutions: 

  • Aluminium
  • Copper
  • Copper alloy 770/nickel silver
  • EMI foil and film
  • EMI foam
  • EMI gaskets
  • EMI silicone
  • EMI tape
  • Pre-tin plated steel 

Invest in Safety Today

Electromagnetic interferences are annoying, but they can also be dangerous. As EMI disrupts healthcare devices and is used to eavesdrop on institutions, the potential negative impacts of EMIs are vast. This is why EMI shielding is essential.

All EMI shielding may do the same task: prevent EMIs from disrupting equipment function or ruining it completely. But not all EMI shields work for every device. Consulting a professional is the ideal course of action to know which shielding option is best for you.

ALT Technologies is at your service when you need adaptive, top-of-the-line EMI shielding solutions in Europe and anywhere else in the world. Our experienced professionals are ready to help you find the shielding solution that best fits your needs, preferences, and budget. Contact us today!





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