Choke ring antenna
Encyclopedia
A choke ring antenna is a particular form of omnidirectional antenna
for use at high frequencies. It consists of a number of conductive concentric cylinders around a central antenna. Due to its delicate construction, it is often enclosed in a protective cover or radome
when placed outside and exposed to the elements.
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 for GPS and radar
applications. In a GPS ground based receiver, a choke ring antenna can provide millimeter precision measurements for surveying
and geological measurement applications.
The choke ring design originated at the Jet Propulsion Laboratory
.
Omnidirectional antenna
In radio communication, an omnidirectional antenna is an antenna which radiates radio wave power uniformly in all directions in one plane, with the radiated power decreasing with elevation angle above or below the plane, dropping to zero on the antenna's axis. This radiation pattern is often...
for use at high frequencies. It consists of a number of conductive concentric cylinders around a central antenna. Due to its delicate construction, it is often enclosed in a protective cover or radome
Radome
A radome is a structural, weatherproof enclosure that protects a microwave or radar antenna. The radome is constructed of material that minimally attenuates the electromagnetic signal transmitted or received by the antenna. In other words, the radome is transparent to radar or radio waves...
when placed outside and exposed to the elements.
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 for GPS and radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
applications. In a GPS ground based receiver, a choke ring antenna can provide millimeter precision measurements for surveying
Surveying
See Also: Public Land Survey SystemSurveying or land surveying is the technique, profession, and science of accurately determining the terrestrial or three-dimensional position of points and the distances and angles between them...
and geological measurement applications.
The choke ring design originated at the Jet Propulsion Laboratory
Jet Propulsion Laboratory
Jet Propulsion Laboratory is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. The facility is headquartered in the city of Pasadena on the border of La Cañada Flintridge and Pasadena...
.
See also
- Trimble Navigation, a manufacturer of this product.
- Patch antennaPatch antennaA patch antenna is a type of radio antenna with a low profile, which can be mounted on a flat surface. It consists of a flat rectangular sheet or "patch" of metal, mounted over a larger sheet of metal called a ground plane. The assembly is usually contained inside a plastic radome, which...
, another antenna for GPS applications. - Magellan Professional ProductsThales NavigationThales Navigation is a global GPS company created in 2001 from the merger of the Magellan Corporation and Thales Navigation, S.A.-Magellan:...
, a manufacturer of this product.
External links
- http://www.javad.com/jns/technology/Choke%20Ring%20Theory.html - Basic choke Ring theory of operation.