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

Extensiones de Documento y Formatos de Documento

Accionado por:

SearchCompliance

SearchSecurity

  • 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 ...

  • password

    A password is an unspaced sequence of characters used to determine that a computer user requesting access to a computer system is...

SearchHealthIT

SearchDisasterRecovery

  • 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.

  • disaster recovery as a service (DRaaS)

    One approach to a strong disaster recovery plan is DRaaS, where companies offload data replication and restoration ...

SearchStorage

  • RAID (redundant array of independent disks)

    RAID (redundant array of independent disks) is a way of storing the same data in different places on multiple hard disks to ...

  • data migration

    Data migration is the process of transferring data between data storage systems, data formats or computer systems.

  • compact disc (CD)

    A compact disc is a portable storage medium that can be used for recording, storing and playing back audio, video and other data ...

SearchSolidStateStorage

  • NVMe (non-volatile memory express)

    NVMe (non-volatile memory express) is a host controller interface and storage protocol to enable a solid-state drive to use the ...

  • SSD RAID (solid-state drive RAID)

    SSD RAID (solid-state drive RAID) is a methodology commonly used to protect data by distributing redundant data blocks across ...

  • Tier 0

    Tier 0 (tier zero) is a level of data storage that is faster, and perhaps more expensive, than any other level in the 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