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A plasma antenna is a type of
radio antenna
In radio engineering, an antenna or aerial is the interface between radio waves propagating through space and electric currents moving in metal conductors, used with a transmitter or receiver. In transmission, a radio transmitter supplies an ...
currently in development in which
plasma is used instead of the metal elements of a traditional antenna.
['Stealth' Antenna Made Of Gas, Impervious To Jamming]
science20.com, published 2007-11-12, accessed 2010-12-14 A plasma antenna can be used for both
transmission and
reception
Reception is a noun form of ''receiving'', or ''to receive'' something, such as art, experience, information, people, products, or vehicles. It may refer to:
Astrology
* Reception (astrology), when a planet is located in a sign ruled by another ...
.
[Plasma Antenna]
Center for Remote Sensing, accessed 2010-12-14 Although plasma antennas have only become practical in recent years, the idea is not new; a patent for an antenna using the concept was granted to J. Hettinger in 1919.
Early practical examples of the technology used
discharge tubes to contain the plasma and are referred to as ionized gas plasma antennas. Ionized gas plasma antennas can be turned on and off and are good for stealth and resistance to electronic warfare and cyber attacks. Ionized gas plasma antennas can be nested such that the higher frequency plasma antennas are placed inside lower frequency plasma antennas. Higher frequency ionized gas plasma antenna arrays can transmit and receive through lower frequency ionized gas plasma antenna arrays. This means that the ionized gas plasma antennas can be co-located and ionized gas plasma antenna arrays can be stacked. Ionized gas plasma antennas can eliminate or reduce co-site interference. Smart ionized gas plasma antennas use plasma physics to shape and steer the antenna beams without the need of phased arrays. Satellite signals can be steered or focused in the reflective or refractive modes using banks of plasma tubes making unique ionized gas satellite plasma antennas. The thermal noise of ionized gas plasma antennas is less than in the corresponding metal antennas at the higher frequencies.
Solid state plasma antennas (also known as plasma silicon antennas) with steerable
directional functionality that can be manufactured using standard
silicon chip fabrication techniques are now also in development.
[Wireless at the speed of plasma]
New Scientist
''New Scientist'' is a magazine covering all aspects of science and technology. Based in London, it publishes weekly English-language editions in the United Kingdom, the United States and Australia. An editorially separate organisation publishe ...
, published 2010-12-13, accessed 2010-12-14 Plasma silicon antennas are candidates for use in
WiGig
WiGig, alternatively known as 60 GHz Wi-Fi, refers to a set of 60 GHz wireless network protocols. It includes the current IEEE 802.11ad standard and also the IEEE 802.11ay standard.
The WiGig specification allows devices to communicate wi ...
(the planned enhancement to
Wi-Fi
Wi-Fi () is a family of wireless network protocols, based on the IEEE 802.11 family of standards, which are commonly used for local area networking of devices and Internet access, allowing nearby digital devices to exchange data by radio wave ...
), and have other potential applications, for example in reducing the cost of vehicle-mounted
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 ...
collision avoidance systems.
Operation
In an ionized gas plasma antenna, a gas is
ionized
Ionization, or Ionisation is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged atom or molecule ...
to create a plasma.
Unlike gases, plasmas have very high
electrical conductivity
Electrical resistivity (also called specific electrical resistance or volume resistivity) is a fundamental property of a material that measures how strongly it resists electric current. A low resistivity indicates a material that readily allow ...
so it is possible for
radio frequency
Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the upp ...
signals to travel through them so that they act as a
driven element
{{Unreferenced, date=April 2016
In a multielement antenna array (such as a Yagi–Uda antenna), the driven element or active element is the element in the antenna (typically a metal rod) which is electrically connected to the receiver or transmi ...
(such as a
dipole antenna) to radiate radio waves, or to receive them. Alternatively the plasma can be used as a
reflector or a
lens
A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...
to guide and focus radio waves from another source.
Solid-state antennas differ in that the plasma is created from
electron
The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family,
and are generally thought to be elementary particles because they have no kn ...
s generated by activating thousands of
diode
A diode is a two-terminal electronic component that conducts current primarily in one direction (asymmetric conductance); it has low (ideally zero) resistance in one direction, and high (ideally infinite) resistance in the other.
A diode ...
s on a silicon chip.
Advantages
Plasma antennas possess a number of advantages over metal antennas, including:
*As soon as the plasma generator is switched off, the plasma returns to a non conductive
gas
Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma).
A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or ...
and therefore becomes effectively invisible to
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 ...
.
[Advances in Plasma Antenna Design]
Alexeff, I ''et al.'', Tennessee University, , , published 2007-05-15, accessed 2010-12-14[Plasma Antennas]
Theodore Anderson, Artech house, 2011,
*They can be dynamically tuned and reconfigured for
frequency
Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is eq ...
,
direction,
bandwidth
Bandwidth commonly refers to:
* Bandwidth (signal processing) or ''analog bandwidth'', ''frequency bandwidth'', or ''radio bandwidth'', a measure of the width of a frequency range
* Bandwidth (computing), the rate of data transfer, bit rate or thr ...
,
gain
Gain or GAIN may refer to:
Science and technology
* Gain (electronics), an electronics and signal processing term
* Antenna gain
* Gain (laser), the amplification involved in laser emission
* Gain (projection screens)
* Information gain in de ...
and
beamwidth, so replacing the need for multiple antennas.
*They are resistant to
electronic warfare
Electronic warfare (EW) is any action involving the use of the electromagnetic spectrum (EM spectrum) or directed energy to control the spectrum, attack an enemy, or impede enemy assaults. The purpose of electronic warfare is to deny the opponen ...
.
*At satellite frequencies, they exhibit much less
thermal noise
A thermal column (or thermal) is a rising mass of buoyant air, a convective current in the atmosphere, that transfers heat energy vertically. Thermals are created by the uneven heating of Earth's surface from solar radiation, and are an example ...
and are capable of faster data rates.
An Electronically Steerable and Focusing Plasma Reflector Antenna and An Electronically Steerable and Focusing Bank of Plasma Tubes
Haleakala Research and Development, accessed 2010-12-14
See also
* List of plasma (physics) articles
References
External links
Antenna having reconfigurable length - United States Patent 6710746
Static Satellite Plasma Antenna
Plasma Antennas: Survey of Techniques and the Current State of the Art
*
{{Antenna Types
Antennas (radio)
Plasma physics
Radio electronics