Loading

Plasma antennas

The future of high-frequency, high-speed wireless communications could very well be plasma antennas capable of transmitting focused radio waves that would quickly dissipate using conventional antennas


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 per cent of the visible universe and perhaps most of what is not visible. Important to antenna technology, plasmas are conductive assemblies of charged and neutral particles and fields that exhibit collective effects. Plasmas carry electrical currents and generate magnetic fields. A plasma antenna is a type of antenna in which the metal-conducting elements of a conventional antenna are replaced by plasma. These are radio frequency antennas that employ plasma as the guiding medium for electromagnetic radiation. The plasma antennas are essentially a cluster of thousands of diodes on a silicon chip that produces a tiny cloud of electrons when charged. These tiny, dense clouds can reflect high-frequency waves like mirrors, focusing the beams by selectively activating particular diodes. The ‘beam-forming’ capability could allow ultra-fast transmission of high data loads—like those needed to seamlessly stream a TV show to an untethered tablet—creating an attractive option for the next generation of supercharged wireless transmitters. Many types of plasma antennas can be constructed, including dipole, loop and reflector antennas. Plasma antennas are interpreted as various devices in which plasma with electric conductivity serves as an emitting element. In gas plasma antenna the concept is to use plasma discharge tubes as the antenna elements. When the tubes are energised, these turn into conductors, and can transmit and receive radio signals. When de-energised, these revert to non-conducting elements and do not reflect probing radio signals. The fact that the emitting element is formed over the interval needed for the emission of an electromagnetic pulse is an important advantage of plasma antennas. In the passive state (in the absence of plasma in the discharge tube), such a device does not exhibit electric conductivity. A plasma stream flowing from a jet into the ambient space, the plasma trace of a body moving at an ultrasonic velocity in the atmosphere, and alternative plasma objects have been studied as possible antenna elements. Solid-state plasma antenna uses beamforming technology and the same manufacturing process that is currently used for silicon chips. That makes it small enough to fit into smartphones. Higher frequencies mean shorter wavelengths and hence smaller antennas...............




Related Posts Plugin for WordPress, Blogger...