Plasma AntennasPritesh Desai (10BEC128)Frenil Shah (10BEC129)
Outline• Introduction• Features of Plasma Antenna• Characteristics of Plasma Antenna• Types of Plasma Antenna• Working Principle• Advantages• Applications
Introduction• What is Plasma? It is a gas in which certain portion of particles are ionized. It responds strongly to electromagnetic fields.
Plasma Antennas• Plasma Antennas is a type of radio antenna currently under development.• Plasma is used instead of metal for conduction.• They can be used for both transmission and reception.
Features• Ability to focus a single beam.• Can communicate signals in very short pulse.• Are Reconfigurable for frequency, bandwidth, gain, length of plasma column and radius of glass tube.• Can transmit and receive for same apertures if the frequencies are widely separated.
Characteristics• Gas ionizing process can manipulate resistance and when deionised, the gas has infinite resistance and doesn’t interact with RF radiation.• After sending pulse, it can be deionised and eliminates "ringing effect".• It can operate up to 90 GHz.
Types of Plasma Antennas• Laser Induced Antenna• Plasma Antennas Using Tube Structures• Explosively Formed Plasma Dielectric Antennas
Laser Induced Antenna• 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.• The laser is used to designate the path of the antenna while an electrical discharge is employed to create and sustain the plasma.
Plasma AntennasUsing Tube Structures• Using tube structures, we can achieve low base-band noise for HF and VHF transmission.• When the plasma creating voltage is turned off, the antenna effectively disappears.
Plasma Dielectric Antenna• A simple explosive charge design, called a plasma cartridge, can be used to generate a column of ionized gas.• In this design. 1-3 grams of seeded explosive charge, which contained Fe, Pb, C, N, K, Cl, and O was used to create plasma.• Due to high temperatures generated by the explosive material, the surrounding gases became ionized, forming a plasma column.
Plasma Dielectric Antenna• The maximum attainable temperature that can be achieved is dependent upon the available oxygen for the fuel recombination.• It has been proven that a plasma jet antenna is feasible.
Electric and MagneticField produced by the antenna
Working Principle• 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.
Working Principle• The resulting pattern forms a rosette of overlapping reflectors only one of which is active at any time.• This enables the beam to be steered quickly without the need for mechanical motion.• When supply is given to the tube, the gas inside it gets ionized to plasma. When plasma is highly energized, it behaves as a conductor.
Working Principle• Antenna generates a localized concentration of plasma to form a plasma mirror that deflects RF beam launched from a central feed located at focus of the mirror.• When plasma jet enters into the spiral field, signals are emitted. The spiral is localized concentration of plasma. These spirals behave as plasma mirrors which help in transmission of RF signals.
Advantages• Plasma posses a high level of conductivity.• Based on the frequencies used, a plasma antenna may be able to receive signals that would not be detectable by older types of antennas, as well as boost signals that are then transmitted out to either point.• a plasma antenna is much less susceptible to electrical damage and can often be repaired much faster if some event does occur to temporary interfere with its function.
Applications• Military applications for its stealth, weight and easily reconfiguration.• Unmanned air vehicle sensor antennas.• Detection and tracking of ballistic missiles.• Telemetry.• Broad-band communications.• Ground penetrating radar.• Wind shear detection and collision avoidance.