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17-09-2009, 01:18 AM
On earth we live upon an island of ordinary matter. The different states of matter generally found on earth are solid, liquid, and gas. Sir William Crookes, an English physicist identified a fourth state of matter, now called plasma, in 1879. Plasma is by far the most common form of matter.
Plasma in the stars and in the tenuous space between them makes up over 99% of the visible universe and perhaps most of that which is not visible. Important to ASI s technology, plasmas are conductive assemblies of charged and neutral particles and fields that exhibit collective effects. Plasmas carry electrical currents and generate magnetic fields. When the Plasma Antenna Research Laboratory at ANU investigated the feasibility of plasma antennas as low radar cross-section radiating elements, Redcentre established a network between DSTO ANU researchers, CEA Technologies, Cantec Australasia and Neolite Neon for further development and future commercialization of this technology. The plasma antenna R & D project and implimentation has proceeded over the last year at the Australian National University in response to a DSTO (Defence Science and Technology Organisation) contract to develop a new antenna solution that minimizes antenna detectability by radar. Since then, an investigation of the wider technical issues of existing antenna systems has revealed areas where plasma antennas might be useful. The project and implimentation attracts the interest of the industrial groups involved in such diverse areas as fluorescent lighting, telecommunications and radar. Plasma antennas have a number of potential advantages for antenna design. When a plasma element is not energized, it is difficult to detect by radar. Even when it is energized, it is transparent to the transmissions above the plasma frequency, which falls in the microwave region. Plasma elements can be energized and de-energized in seconds, which prevents signal degradation. When a particular plasma element is not energized, its radiation does not affect nearby elements. HF CDMA Plasma antennas will have low probability of intercept( LP) and low probability of detection( LPD ) in HF communications. Plasma antennas are radio frequency antennas that employ plasma as the guiding medium for electromagnetic radiation.The concept is to use plasma discharge tubes as the antenna elements. When the tubes are energized, they become conductors, and can transmit and receive radio signals. When they are de-energised, they revert to non-conducting elements and do not reflect probing radio signals. Plasma antenna can be Steered electronically. Another feature of the plasma antenna is that it can be turned off rapidly, reducing ringing on pulse transmission.
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29-06-2010, 06:24 PM
Development of microwave devices tasks some new problems in the antenna systems theory and practice. Decreasing dimensions and weight of the radiating elements keeps to be the traditional and current question. In the making of power and superpower pulse sources the wide band of the work frequencies (from tens MHz to tens GHz) achievement is a current question too. Pulse power levels obtained now in such sources have the units of GW values. That power is determined by high values of the antenna input voltage (units of megavolts). It can leads to breakdowns in the feeder and antenna. Such a problem also arise in the making of mobile sources that have power of tens megawatt value. When such sources are made on the magnetic cumulative generator (MCG)  base the task of decreasing of dimensions and weight of them keeps to be relevant. MCG operation principle is grounded on transformation of explosive material potential energy into electromagnetic energy. The output voltage in such generators exceeds 30KV value under there volume in 0.5l and mass in 300g values. It is clearly that practical realization of such a source requires making unconventional decisions in the developing both feeder and antenna. One of the possible ways of the problems decision is the plasma antenna application.
In recent years, the rapid growth in both communications and radar systems has led to a concomitant growth in the possible applications and requirements of antennas. These new requirements include compactness and conformality, rapid reconfigurability for directionality and frequency agility and for military applications should also allow low absolute or out-of-band radar cross-section and facilitate low probability of intercept communications. Investigations have recently begun on the use of ionised gases or plasmas as the conducting medium in antennas that could satisfy these requirements. Such plasma antennas may even offer a viable alternative to metal in existing applications when overall technical requirements are considered. . Possibilities of the plasma application for antenna parameters control have been proposed in the sixties of 20 century. In work the test data of 10Ghz signal transmission are presented. The transmission was realized along a plasma channel that was created by the atmosphere breakdown. The atmosphere breakdown was created by the focused laser emission. Only a few works are known, for example , that carries results of calculations of electromagnetic field reflected by surface girded by plasma layer. It was experimental shown that an interaction of the magnetized plasma and the shortcut dipole girded by the plasma leads to increasing of the signal power emitted into a free space . But there is insufficient quantity of the works dedicated to development of the plasma antennas designed for work in the terrestrial atmosphere conditions. Methodical researches in that area have not done yet. This work object is to fill in a varying degree that vacuum.
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10-10-2010, 12:12 PM
Plasma antennas are radio frequency antennas that employ plasma as the guiding medium for electromagnetic radiation.Here, plasma discharge tubes are used as the antenna elements. the tubes become conductors when they are energised and can transmit and receive radio signals. And they revert to non-
conducting elements when de-energized. In this state they do not reflect
probing radio signals.Plasma antenna can be "Steered" electronically. It can also be turned off rapidly reducing the effect of ringing on pulse on transmission.
PLASMA ANTENNA TECHNOLOGY
The antenna design has been an integral part of virtually every communication and radar application. For all kinds of applications which range from general broadcast of radio frequency signals for public use to complex weapon systems, there are specialized antennas available. Plasma antenna technology employs ionized gas enclosed in a tube (or other enclosure) as the conducting element of an antenna.Whereas the conventional antennas use solid metal wires as the conducting element. The design allows for extremely short pulses, important to many forms of digital communication and radars.compact and dynamically reconfigurable antennas are produced easily with this technology.
For full details and report download, visit these pages:
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15-10-2010, 11:15 AM
PLASMA ANTENA.ppt (Size: 2.93 MB / Downloads: 775)
This article is presented by:
MODEL POLYTECHNIC COLLEGE VADAKARA
DEPT : APPLIED ELECT RONICS
WHAT IS PLASMA ?
On earth we live upon an island of "ordinary" matter. The different states of matter generally found on earth are solid, liquid, and gas. Sir William Crookes, an English physicist identified a fourth state of matter, now called plasma, in 1879.
Plasma is by far the most common form of matter.
Plasma in the stars and in the tenuous space between them makes up over 99% of the visible universe and perhaps most of that which is not visible.
Important to ASI's technology, plasmas are conductive assemblies of charged and neutral particles and fields that exhibit collective effects. Plasmas carry electrical currents and generate magnetic fields.
PLASMA ANTENNA TECHNOLOGY
Plasma antenna technology employs ionized gas enclosed in a tube (or other enclosure) as the conducting element of an antenna. This is a fundamental change from traditional antenna design that generally employs solid metal wires as the conducting element.
Ionized gas is an efficient conducting element with a number of important advantages. Since the gas is ionized only for the time of transmission or reception," ringing" and associated effects of solid wire antenna design are eliminated.
The design allows for extremely short pulses, important to many forms of digital communication and radars.
UNIQUE FEATURE OF PLASMA ANTENNA
One fundamental distinguishing feature of a plasma antenna is that the gas ionizing process can manipulate resistance.
A second fundamental distinguishing feature is that after sending a pulse the plasma antenna can be deionized, eliminating the ringing associated with traditional metal elements. Ringing and the associated noise of a metal antenna can severely limit capabilities in high frequency short pulse transmissions.
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22-01-2011, 05:22 PM
PLASMA ANTENNA1.ppt (Size: 713.5 KB / Downloads: 437)
BY RAVINDRA REDDY N
The fourth state of matter, now called plasma .
Conductive assemblies of charged and neutral particles.
Carry electrical currents and generate magnetic fields.
In antenna’s the conducting element (metal) is replaced by plasma
Plasma elements can be energized and de–energized in seconds.
Hence prevents signal degradation.
Types ex: dipole antenna, a loop antenna and reflector antennas.
OVERVIEW ON PLASMA ATENNA TECHNOLOGY
Antenna design has been an integral part of virtually every communication and radar application
Antenna represents a conducting metal surface that is sized to emit radiation at one or more selected frequencies
Employs ionized gas enclosed in a tube
Employs solid metal wires as the conducting element
"ringing" and associated effects of solid wire antenna design are eliminated
When gas is charged, it becomes conductive, allowing radio frequency (RF) signals to be transmitted or received
performance is equal to a copper wire antenna in every respect.
It can be used over a large frequency range up to 20GHz
Can employ a wide variety of gases
TYPES OF PLASMA ANTENNAS
1: Helical plasma antenna
2:Spiral plasma antenna
3: Planer array plasma antenna
MARKET APPLICATIONS OF PLASMA TECHNOLOGY
Antenna and Transmission Line Applications
Plasma Mirrors (Reflectors) and Lenses
Potential military applications include:
Shipboard/submarine antenna replacements.
Unmanned air vehicle sensor antennas.
IFF ("identification friend or foe") land-based vehicle antennas.
Stealth aircraft antenna replacements.
Broad band jamming equipment including for spread-spectrum emitters.
ECM (electronic counter-measure) antennas.
Phased array element replacements.
Detection and tracking of ballistic missiles
Side and back lobe reduction
commercial applications in telemetry, broad-band communications, ground penetrating radar, navigation, weather radar, wind shear detection and collision avoidance, high-speed data (for example Internet) communication spread spectrum communication, and cellular radiation protection.
Filters and Phase Shifters
microwave band pass filter
The input signal is dissipated in the load, or reflective, allowing the input signal to return to the circulator and exit the device.
By changing the plasma parameters the pass band of the filter can be modified.
multiple plasma columns could be inserted
Variable time delay can be obtained by switching in different numbers of segments between the plasma columns
The presence of a controlled amount of plasma in traveling-wave tubes and backward-wave oscillators can lead to improvement in their operating characteristics above those of evacuated devices. Specifically, the bandwidth and power handling capability can be increased
UNIQUE CHARACTERISTICS OF PLASMA ANTENNA
The gas ionizing process can manipulate resistance
After sending a pulse the plasma antenna can be de-ionized, eliminating the ringing associated with traditional metal elements.
When de-ionized, the gas has infinite resistance and does not interact with RF radiation.
When de-ionized the gas antenna will not backscatter radar waves (providing stealth) and will not absorb high-power microwave radiation (reducing the effect of electronic warfare countermeasures).
It provides increased accuracy and reduces computer signal processing requirements.
These advantages are important in cutting edge applications for impulse radar and high-speed digital communications.
Based on the results of development to date, plasma antenna technology has the following additional attributes
No antenna ringing provides an improved signal to noise ratio and reduces multipath signal distortion.
Reduced radar cross section provides stealth due to the non-metallic elements.
Changes in the ion density can result in instantaneous changes in bandwidth over wide dynamic changes.
After the gas is ionized, the plasma antenna has virtually no noise floor
A circular scan can be performed electronically with no moving parts at a higher speed than traditional mechanical antenna structures.
It has been mathematically illustrated that by selecting the gases and changing ion density that the electrical aperture (or apparent footprint) of a plasma antenna can be made to perform on par with a metal counterpart having a larger physical size.
low ionization level can be decoupled from an adjacent high-frequency transmitter
Can transmit and receive from the same aperture provided the frequencies are widely separated.
Plasma resonance, impedance and electron charge density are all dynamically reconfigurable.
A single dynamic antenna structure can use time multiplexing
Hence many RF subsystems can share one antenna resource reducing the number and size of antenna structures
plasma antenna technology has been studied and characterized by ASI Technology Corporation
The work was carried out in part through two ONR sponsored contracts
NCCOSC RDTE Division, San Diego, awarded contract N66001-97-M-1153 1 May 1997.
The major objective of the program was to determine the noise levels associated with the use of gas plasma as a conductor for a transmitting and receiving antenna.
The second contract N00014-98- C-0045 was a 6-month SBIR awarded by ONR on November 15, 1997
The major objective of this effort was to characterize the GP antenna for conductivity, ionization breakdowns, upper frequency limits, excitation and relaxation times, ignition mechanisms, temperatures and thermionic noise emissions and compare these results to a reference folded copper wire monopole.
ASI Technology Corporation is under contract with General Dynamics Electric Boat Division and in conjunction with the Plasma Physics Laboratory at the University of Tennessee, an inflatable plasma antenna is being developed.
This antenna is designed to operate at 2.4 GHz and would be mounted on the mast of an attack submarine.
In addition a prototype plasma waveguide and plasma reflector has been designed and demonstrated to General Dynamics.
TECHNOLOGICAL CONCEPTS OF PLASMA ANTENNAS
Higher Efficiency and Gain
Reconfiguration and Multi functionality
Reduced interference and ringing
Change shape to control patternand bandwidth
Change plasma parameters
Glow discharge increases
visible signature *
Good RF coupling for electrically small antennas
Stable and repeatable
Flexibility in length and direction of path
Ionization and decay times limit
Plasma volumes must be stable
Ionizer adds weight and volume
Ionizer increases power Consumption
Not durable or flexible
Higher ionization energy than
for a tube
As part of a “blue skies” research program, DSTO has teamed up with the ANU’s Plasma Research Laboratory to investigate the possibility of using plasmas like those generated in fluorescent ceiling lights, for antennas
The fact that metal structures cannot be easily moved when not in use limits in some aspects of antenna array design.
It can also pose problems when there is a requirement to locate many antennas in a confined area
Weapons System Division has been studying the concept of using plasma columns for antennas, and has begun working in collaboration with ANU.
The type of plasma antenna under investigation is constructed using a hollow glass column which is filled with an inert gas
The metal whips that may be considered for a plasma replacement are anywhere from a few centimeters to several meters long.
DSTO and ANU are now investigating the commercialization of the technology.
Plasma antenna technology offers the possibility of building completely novel antenna arrays, as well as radiation pattern control and lobe steering mechanisms that have not been possible before.
The research may one day have far reaching applications from robust military antennas through to greatly improve external television aerials
To date, the research has produced many novel antennas using standard fluorescent tubes and these have been characterized and compare favorably with their metal equivalents..
For example, a 160 MHz communications link was demonstrated using plasma antennas for both base and mobile stations.
Current research is working towards a robust plasma antenna for field demonstration to Defense Force personnel
REFERENCES & BIBILOGRAPHY
J Drummond, Plasma Physics, McGraw-Hill.
M. Heald and C. Warton, Plasma Diagnostics with Microwaves, Krieger Publishing Co.
ASI Technology Corporation web page: asiplasma
W. Manheimer, “Plasma Reflectors for Electronic Beam Steering in Radar Systems,”
IEEE Transactions on Plasma Science.
1. J. Hettinger, “Aerial Conductor for Wireless Signaling and Other Purposes,” Patent
number 1,309,031, July 8, 1919.22
2. V. L. Ginzburg, The Propagation of Electromagnetic Waves in Plasmas, Pergamon
3. J. Drummond, Plasma Physics, McGraw-Hill, 1961.
4. M. Heald and C. Warton, Plasma Diagnostics with Microwaves, Krieger Publishing Co.,
5. U. Inan and A. Inan, Electromagnetic Waves, Prentice-Hall, 2000.
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12-02-2011, 03:02 PM
i want a document of plasma antenna.
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02-03-2011, 03:49 PM
Kumari Nisha Mishra
SEMINAR PRESENTATION.ppt (Size: 798.5 KB / Downloads: 316)
What is Plasma ?
By supplying energy the states of matter changes: from solid to liquid and from liquid to gas. If further energy is added to a gas it becomes ionized and passes over into the Plasma state – a fourth state of matter.
Plasma is a gas in which a certain portion of the particles are ionized. The presence of a non-negligible number of charge carriers makes the plasma electrically conductive so that it responds strongly to electromagnetic fields.
Plasma – the fourth aggregate state of matter was identified by an English physicist Sir William Crooks in 1879.
Plasma has properties quite unlike those of solids, liquids, or gases and is considered be a distinct state of matter.
What is plasma antenna technology?
Plasma antenna technology is that which employs ionized gas enclosed in a tube as conducting element.
This is a fundamental change from traditional antenna design that generally employs solid metal wires as the conducting element.
Ionized gas is an efficient conducting element with a number of important advantages. Since the gas is ionized only for the time of transmission or reception, ringing and associated effects of solid wire antenna design are eliminated.
This technology has advanced to provide unique antenna designs for applications ranging from general broadcast of radio frequency signals for public use to complex weapon systems.
Features Of Plasma Antenna
Plasma antenna has the ability to focus a signal beam easily and to communicate signals in very short pulses, which could prove extremely useful in the areas of digital communications and radar.
Changes in the ion density can result in instantaneous changes in bandwidth over wide dynamic range.
Plasma Antenna are reconfigurable for frequency, bandwidth, gain, length of plasma column, radius of glass tube.
Plasma Antenna can transmit and receive from same aperture provided the frequencies are widely separated.
How does Plasma antenna works?
A plasma antenna generates localized concentrations of plasma to form a plasma mirror which deflects an RF beam launched from a central feed located at the focus of the mirror.
An ionized region, or solid state plasma, can be generated in silicon using electronically controlled devices (plasma diodes) that are positioned between closely spaced metalized surfaces which constrain the beam.
The plasma can be freely moved by switching groups of plasma diodes on and off that follow the desired geometry of the reflector
The resulting pattern of plasma diodes forms a rosette of overlapping reflectors only one of which is active (i.e. reflecting) at any one time. This enables the beam to be steered quickly without the need for mechanical motion.
In some realizations, the silicon disc (ie Si wafer) can act as a cylindrical lens, to form a lens or reflector system that enables the RF energy to be collimated. Working of Plasma antenna is shown in the figure:
Diagram showing working of Plasma antenna
How Plasma Antenna different from Traditional Antenna? Plasma Antenna Traditional Antenna
1. Electronic movement is made even more easily inside the plasma antenna, because of electrons are in a free state inside the hot gas.
Solid metal antenna can function because electrons move freely in the metal conductor.
Traditional antenna are less efficient, more in weight and larger in size.
Traditional antenna can’t be easily switched on and off.
Some types of Plasma antenna
Multiple Tube Plasma Antenna
Selectable Multibeam Antenna
Advantages of Plasma antenna
Compact and light weight
Disadvantages of Plasma antenna
Applications of Plasma Antenna
Plasma antenna has a number of applications in defense, space and homal appliances.
Network Equipment Providers and Systems Integrators
Networks Sensing Defense
In Microwave Communication Plasma Antenna Provide Ease for realignment of long range directional antennas. -Low Cost for the network owner.
Antennas constructed of metal can be big and bulky, and are normally fixed in place. The fact that metal structures cannot be easily moved when not in use limits some aspects of antenna array design.
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30-04-2011, 11:50 AM
PLASMA ANTENNA FINAL PPT.ppt (Size: 1.63 MB / Downloads: 224)
Plasma Antenna is a special type of antenna in which the metal conducting elements of a conventional antenna are replaced by a plasma.
Fourth state of matter similar to gas.
Sir William Crookes, an English Physicist identified it in 1879.
According to Markland’s technology, plasmas are conductive assemblies of charged and neutral particles and fields that exhibit collective effects.
It is defined as an electrical conductor of a specific length that radiate radiowaves generated by a transmitter and collect that waves at the receiver.
GENERATION OF ELECTRIC AND MAGNETIC FIELD
When voltage applied to an antenna,electric field produced.
Causes current to flow in antenna.
Due to current flow,magnetic field produced.
These two fields are emitted from an antenna and propagate through space over very long distances.
PLASMA ANTENNA TECHNOLOGY
It employs an ionized gas enclosed in a tube as the conducting element of an antenna.
When the gas is electrically charged or ionized to a plasma,it becomes conductive and allowing radio frequency signals to be transmitted or received.
When gas is not ionized,the antenna element ceases to exit.
IONIZED GAS PLASMA ANTENNA
FIGURE OF PLASMA TUBE ANTENNA
When supply is given to the tube, the gas inside it gets ionised to plasma.
When plasma is highly energised, it behaves as a conductor.
Antenna generates a localised concentration of plasma to form a plasma mirror that deflects RF beam launched from a central feed located at focus of mirror.
WORKING PRINICIPLE FIGURE
A plasma jet has diameter ‘a’ is formed in the atmosphere and passes through a dielectric cylinder that has diameter ‘b’ and a conductive spiral is winded on the cylinder.
FIGURE OF PLASMA ANTENNA DESIGN:
When plasma jet enters into the spiral field, signals are emitted.
The spiral is a localised concentration of plasma.
These spirals behave as plasma mirrors which helps in transmission of RF signals.
In highspeed digital communication and radar system.
In radio antenna.
Stealth for millitary application.
Used for transmission and modulation techniques(PM,AM,FM).
Low in weight
Smaller in size
It is more advantageous than other antenna due to ionized gas.
Its action has many general with the dielectric antenna action.
It helps in pulse operation.
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30-10-2011, 03:26 PM
CAN I GET THE INFORMATION ABOUT PSUDO-SATELITES
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31-10-2011, 09:40 AM
To get more information about the topic "plasma antennas " please refer the link below
topicideashow-to-plasma-antennas-seminar and presentation-required
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10-10-2012, 10:48 AM
plasma antenna.doc (Size: 92 KB / Downloads: 29)
A plasma antenna is a type of radio antenna currently in development in which plasma is used instead of the metal elements of a traditional antenna. A plasma antenna can be used for both transmission and reception 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 is solid state plasma antennas (also known as plasma silicon antennas) with steerable directional functionality that can be manufactured using standard silicon chip fabrication technique are now also in development. Plasma silicon antennas are candidates for use in WiGIg (the planned enhancement toWi-Fi), and have other potential applications, for example in reducing the cost of vehicle-mounted radar collosion avoidance system
In an ionized gas plasma antenna, a gas is ionized to create a plasma. Unlike gases, plasmas have very high electrical conductivity so it is possible for radio frequency signal signals to travel through them so that they act as a driven element (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 to guide and focus radio waves from another source.
Solid-state antennas differ in that the plasma is created from electrons generated by activating thousands of diodes on a silicon chip.
Plasma Antenna Technology
It employs ionized gas enclosed in a tube as the conducting element of an antenna. . This is a fundamental change from traditional antenna design that generally employs solid metal wires as the conducting element. The gas is ionized only for the time of transmission or reception.
How Does Plasma Antenna Work?
Plasma antenna - conducting element - ionized gas enclosed in a tube as a of an antenna.
When the Gas is ionized to a plasma state -then it becomes conductive, allowing radio frequency (RF) signals to be transmitted or receivedIn order for plasma to have significant effect on an electromagnetic wave, the electronic density must be increased by several orders of magnitude.When the gas is not ionized or a plasma antenna is turned off - it is transparent and allowing other adjacent antennas to transmit or receive without interference.
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29-10-2013, 12:44 PM
i want seminar and presentation report for plasma antenna