Browse Definitions:
Definition

omnidirectional antenna

An omnidirectional antenna is a wireless transmitting or receiving antenna that radiates or intercepts radio-frequency (RF) electromagnetic fields equally well in all horizontal directions in a flat, two-dimensional (2D) geometric plane. Omnidirectional antennas are used in most consumer RF wireless devices, including cellular telephone sets and wireless routers.

In theory, a vertically oriented, straight conductor such as a dipole antenna measuring no more than 1/2 wavelength from end-to-end always exhibits omnidirectional properties in a horizontal (azimuth) plane. Multiple collinear (in-line) vertical dipoles also exhibit omnidirectional behavior in the azimuth plane; they can offer improved performance over a single dipole in some applications. If the conductor axis is not oriented vertically, then the antenna radiates and receives equally well in all directions in the plane through which the conductor passes at a right angle. However, this ideal state of affairs exists only in the absence of obstructions or other nearby conducting objects. In practice, surrounding objects (such as the user of a cell phone set or a computer next to a wireless router) distort the radiation and reception pattern.

In the usual context, a so-called omnidirectional antenna does not perform equally well in all possible directions in three-dimensional (3D) space. Such a device, which can exist only in theory but can be approached in practice, is called an isotropic antenna or isotropic radiator.

Antennas that offer enhanced performance in some directions, at the expense of other directions, are called directional antennas or directional radiators. The most common example is the dish antenna used with satellite internet, satellite television, and space-communications installations. Other examples include the Yagi antenna, quad antenna, billboard antenna, and helical antenna.

 

This was last updated in December 2016

Continue Reading About omnidirectional antenna

Join the conversation

1 comment

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.

In theory an omnidirectional antenna is capable of picking up or transmitting signals from/to any direction, but this cannot be achieved entirely in practice, because the limitation placed by objects that surround the antenna which alter or distort its propagation field. This field is further distorted if the antenna is horizontally polarized. All practical omni antennas have these limitations. http://www.omnitenna.com
Cancel

-ADS BY GOOGLE

File Extensions and File Formats

SearchCompliance

  • internal audit (IA)

    An internal audit (IA) is an organizational initiative to monitor and analyze its own business operations in order to determine ...

  • pure risk (absolute risk)

    Pure risk, also called absolute risk, is a category of threat that is beyond human control and has only one possible outcome if ...

  • risk assessment

    Risk assessment is the identification of hazards that could negatively impact an organization's ability to conduct business.

SearchSecurity

  • phishing

    Phishing is a form of fraud in which an attacker masquerades as a reputable entity or person in email or other communication ...

  • vulnerability disclosure

    Vulnerability disclosure is the practice of publishing information about a computer security problem, and a type of policy that ...

  • incident response

    Incident response is an organized approach to addressing and managing the aftermath of a security breach or cyberattack, also ...

SearchHealthIT

SearchDisasterRecovery

  • business continuity and disaster recovery (BCDR)

    Business continuity and disaster recovery (BCDR) are closely related practices that describe an organization's preparation for ...

  • 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 ...

SearchStorage

  • flash memory

    Flash memory, also known as flash storage, is a type of nonvolatile memory that erases data in units called blocks.

  • NAND flash memory

    NAND flash memory is a type of nonvolatile storage technology that does not require power to retain data.

  • NOR flash memory

    NOR flash memory is one of two types of nonvolatile storage technologies.

SearchSolidStateStorage

  • hybrid hard disk drive (HDD)

    A hybrid hard disk drive is an electromechanical spinning hard disk that contains some amount of NAND Flash memory.

Close