Browse Definitions:
Definition

EM shielding (electromagnetic shielding)

Contributor(s): Matthew Haughn

EM shielding (electromagnetic shielding) is the practice of surrounding electronics and cables with conductive or magnetic materials to guard against incoming or outgoing emissions of electromagnetic frequencies (EMF).  

EM shielding is conducted for several reasons. The most common purpose is to prevent electromagnetic interference (EMI) from affecting sensitive electronics. Metallic mesh shields are often used to protect one component from affecting another inside a particular device. In a smartphone, for example, a metallic shield protects electronics from its cellular transmitter/receiver. Radiation shields in mobile phones also decrease the amount of radio frequency (RF) energy that might be absorbed by the user. 

To increase the security of air gapped systems, EM shielding is advised. Conventionally, physical isolation and a lack of external connectivity have been considered adequate to ensure their security. However, proof-of-concept attacks have demonstrated that acoustical infection can be enabled by exploiting the electromagnetic emanations of the system’s sound card.

Air-gapping is used in the military, government and financial systems like stock exchanges. The measures are also used by reporters, activists and human rights organizations working with sensitive information. 

A number of different materials and techniques are used for EM shielding. Wires may be surrounded by a metallic foil or braid shield to block errant EMI from the cased wires. Audio speakers often have inner metallic casing to block EMI produced by the drivers so they don’t affect TVs and other electronics. Complete continuous enclosure is not necessary so long as any openings are smaller than the electromagnetic waves that need to be blocked.

Special conductive paints can be used to prevent the EMF from networks escaping the originating business to prevent eavesdropping or wireless attacks. These techniques are like a miniature Faraday cage, which can prevent signal corruption that would cause electronics to perform unexpectedly. 

Electronics may also have connections filtered for EMI by use of electronic components like capacitors, ferrules and grounded wires to minimize the effects of EMI noise -- even twisting wires together with grounds can reduce lower interference.

Magnetic materials must be used for EM shielding in environments where the magnetic fields are slowly varied below the 100Khz range as a Faraday cage-type solution is ineffective in that situation. With magnetic materials, the EMI is drawn into the magnetic field of the shielding.

This was last updated in August 2014

Continue Reading About EM shielding (electromagnetic shielding)

Start the conversation

Send me notifications when other members comment.

By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy

Please create a username to comment.

-ADS BY GOOGLE

File Extensions and File Formats

SearchCompliance

SearchSecurity

  • black hat

    Black hat refers to a hacker who breaks into a computer system or network with malicious intent.

  • copyright

    Copyright is a legal term describing ownership of control of the rights to the use and distribution of certain works of creative ...

  • keylogger (keystroke logger or system monitor)

    A keylogger, sometimes called a keystroke logger or system monitor, is a type of surveillance technology used to monitor and ...

SearchHealthIT

  • population health management (PHM)

    Population health management (PHM) is a discipline within the healthcare industry that studies and facilitates care delivery ...

  • ICD-10-PCS

    The International Classification of Diseases, 10th Revision, Procedure Coding System (ICD-10-PCS) is a U.S. cataloging system for...

  • U.S. National Library of Medicine (NLM)

    The U.S. National Library of Medicine (NLM) is the largest biomedical library in the world.

SearchDisasterRecovery

  • business continuity plan (BCP)

    A business continuity plan (BCP) is a document that consists of the critical information an organization needs to continue ...

  • call tree

    A call tree -- sometimes referred to as a phone tree -- is a telecommunications chain for notifying specific individuals of an ...

  • mass notification system (MNS)

    A mass notification system is a platform that sends one-way messages to inform employees and the public of an emergency.

SearchStorage

  • open source storage

    Open source storage is data storage software developed in a public, collaborative manner that permits the free use, distribution ...

  • CompactFlash card (CF card)

    A CompactFlash card (CF card) is a memory card format developed by SanDisk in 1994 that uses flash memory technology to store ...

  • email archiving

    Email archiving (also spelled e-mail archiving) is a systematic approach to saving and protecting the data contained in email ...

SearchSolidStateStorage

  • RRAM or ReRAM (resistive RAM)

    RRAM or ReRAM (resistive random access memory) is a form of nonvolatile storage that operates by changing the resistance of a ...

  • JEDEC

    JEDEC is a global industry group that develops open standards for microelectronics.

  • M.2 SSD

    An M.2 SSD is a solid-state drive (SSD) that conforms to a computer industry specification written for internally mounted storage...

SearchCloudStorage

  • RESTful API

    A RESTful application program interface breaks down a transaction to create a series of small modules, each of which addresses an...

  • cloud storage infrastructure

    Cloud storage infrastructure is the hardware and software framework that supports the computing requirements of a private or ...

  • Zadara VPSA and ZIOS

    Zadara Storage provides block, file or object storage with varying levels of compute and capacity through its ZIOS and VPSA ...

Close