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A choke ring antenna is a particular form of
omnidirectional antenna
In radio communication, an omnidirectional antenna is a class of antenna which radiates equal radio power in all directions perpendicular to an axis (azimuthal directions), with power varying with angle to the axis ( elevation angle), declining ...
for use at high frequencies ( VHF & UHF). It consists of a number of concentric
In geometry, two or more objects are said to be concentric, coaxal, or coaxial when they share the same center or axis. Circles, regular polygons and regular polyhedra, and spheres may be concentric to one another (sharing the same center point ...
conductive cylinders around a central antenna.
Due to its intricate construction, it is often enclosed in a protective cover or radome
A radome (a portmanteau of radar and dome) is a structural, weatherproof enclosure that protects a radar antenna. The radome is constructed of material transparent to radio waves. Radomes protect the antenna from weather and conceal antenna e ...
when placed outside and exposed to the elements.
Benefits
Choke ring antennas are notable for their ability to reject multipath signals from a source. Since the path that a signal takes from a transmitter to receiver can be used to measure the distance between the two, this makes it highly suited forGPS
The Global Positioning System (GPS), originally Navstar GPS, is a Radionavigation-satellite service, satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of t ...
and radar
Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...
applications. In a GPS ground-based receiver, a choke ring antenna can provide millimeter precision measurements for use in surveying
Surveying or land surveying is the technique, profession, art, and science of determining the terrestrial two-dimensional or three-dimensional positions of points and the distances and angles between them. A land surveying professional is ca ...
and geological measurements.
The choke ring design was originally developed at the Jet Propulsion Laboratory
The Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center in the City of La Cañada Flintridge, California, United States.
Founded in the 1930s by Caltech researchers, JPL is owned by NASA an ...
. - A basic description of choke ring antenna benefits and limitations.
See also
*Trimble Inc.
Trimble Inc. is an American software, hardware, and services technology company. Trimble supports global industries in building & construction, agriculture, geospatial, natural resources and utilities, governments, transportation and others. Trim ...
- one manufacturer of this product.
* Patch antenna
A patch antenna is a type of antenna with a low profile, which can be mounted on a surface. It consists of a planar rectangular, circular, triangular, or any geometrical sheet or "patch" of metal, mounted over a larger sheet of metal called a g ...
- another antenna for GPS applications.
* Magellan Navigation
Magellan Navigation, Inc. is an American producer of consumer and professional grade global positioning system receivers, named after Ferdinand Magellan, the first explorer to circumnavigate the globe. Headquartered in San Dimas, California, with E ...
- another manufacturer of this product.
Notes
External links
* - Basic choke Ring theory of operation. Radio frequency antenna types Antennas (radio) {{radio-comm-stub