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Monopole Antenna
A monopole antenna is a class of radio antenna consisting of a straight rod-shaped conductor, often mounted perpendicularly over some type of conductive surface, called a ground plane. The driving signal from the transmitter is applied, or for receiving antennas the output signal to the receiver is taken, between the lower end of the monopole and the ground plane. One side of the antenna feedline is attached to the lower end of the monopole, and the other side is attached to the ground plane, which is often the Earth. This contrasts with a dipole antenna which consists of two identical rod conductors, with the signal from the transmitter applied between the two halves of the antenna. The monopole is often used as a resonant antenna; the rod functions as an open resonator for radio waves, oscillating with standing waves of voltage and current along its length. Therefore the length of the antenna is determined by the wavelength of the radio waves it is used with. The most co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Random Wire Antenna
A random wire antenna is a radio antenna consisting of a long wire suspended above the ground, whose length does not bear a particular relation to the wavelength of the radio waves used, but is typically chosen more for convenience. The wire may be straight or it may be strung back and forth between trees or walls just to get enough wire into the air. Due to the great variability of the (unplanned) antenna structure, effectiveness can vary wildly from one installation to another. Random wire antennas are typically fed at one end against a suitable counterpoise (such as earth ground). They are widely used as receiving antennas on the long wave, medium wave, and short wave bands, as well as transmitting antennas on these bands for small outdoor, temporary or emergency transmitting stations, as well as in situations where more permanent antennas cannot be installed. Random wire and long wire Often random wire antennas are also (inaccurately) referred to as long-wire antenna. Ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Azimuth
An azimuth (; from ar, اَلسُّمُوت, as-sumūt, the directions) is an angular measurement in a spherical coordinate system. More specifically, it is the horizontal angle from a cardinal direction, most commonly north. Mathematically, the relative position vector from an observer (origin) to a point of interest is projected perpendicularly onto a reference plane (the horizontal plane); the angle between the projected vector and a reference vector on the reference plane is called the azimuth. When used as a celestial coordinate, the azimuth is the horizontal direction of a star or other astronomical object in the sky. The star is the point of interest, the reference plane is the local area (e.g. a circular area with a 5 km radius at sea level) around an observer on Earth's surface, and the reference vector points to true north. The azimuth is the angle between the north vector and the star's vector on the horizontal plane. Azimuth is usually measured in d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiation Pattern
In the field of antenna design the term radiation pattern (or antenna pattern or far-field pattern) refers to the ''directional'' (angular) dependence of the strength of the radio waves from the antenna or other source.Constantine A. Balanis: “Antenna Theory, Analysis and Design”, John Wiley & Sons, Inc., 2nd ed. 1982 David K Cheng: “Field and Wave Electromagnetics”, Addison-Wesley Publishing Company Inc., Edition 2, 1998. Edward C. Jordan & Keith G. Balmain; “Electromagnetic Waves and Radiating Systems” (2nd ed. 1968) Prentice-Hall. Particularly in the fields of fiber optics, lasers, and integrated optics, the term radiation pattern may also be used as a synonym for the near-field pattern or Fresnel pattern.Institute of Electrical and Electronics Engineers, “The IEEE standard dictionary of electrical and electronics terms”; 6th ed. New York, N.Y., Institute of Electrical and Electronics Engineers, c1997. IEEE Std 100-1996. d. Standards Coordinating Committee 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Omnidirectional Antenna
In radio communication, an omnidirectional antenna is a class of antenna which radiates equal radio power in all directions perpendicular to an axis (azimuthal directions), with power varying with angle to the axis (elevation angle), declining to zero on the axis. When graphed in three dimensions ''(see graph)'' this radiation pattern is often described as ''doughnut-shaped''. Note that this is different from an isotropic antenna, which radiates equal power in ''all'' directions, having a ''spherical'' radiation pattern. Omnidirectional antennas oriented vertically are widely used for nondirectional antennas on the surface of the Earth because they radiate equally in all horizontal directions, while the power radiated drops off with elevation angle so little radio energy is aimed into the sky or down toward the earth and wasted. Omnidirectional antennas are widely used for radio broadcasting antennas, and in mobile devices that use radio such as cell phones, FM radios, walkie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monopole Antenna Radiation Patterns
Monopole may refer to: * Magnetic monopole, or Dirac monopole, a hypothetical particle that may be loosely described as a magnet with only one pole * Monopole (mathematics), a connection over a principal bundle G with a section (the Higgs field) of the associated adjoint bundle * ''Monopole'', the first term in a multipole expansion * Monopole (wine), an appellation owned by only one winery * ''Monopole'' (album), a 2011 album by White Town * Monopole antenna, a radio antenna that replaces half of a dipole antenna with a ground plane at right-angles to the remaining half * Monopole, a tubular self-supporting telecommunications mast * ''The Monopole'', a bar in Plattsburgh, NY * Établissements Monopole, a French auto parts manufacturer, racing car builder and racing team. See also * Dipole, a particle with a north and south pole * Dyon, a particle with electric and magnetic charge * Instanton, a class of field solutions that includes monopoles * Monomial, a polynomial which has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monopole And Image Antenna
Monopole may refer to: * Magnetic monopole, or Dirac monopole, a hypothetical particle that may be loosely described as a magnet with only one pole * Monopole (mathematics), a connection over a principal bundle G with a section (the Higgs field) of the associated adjoint bundle * ''Monopole'', the first term in a multipole expansion * Monopole (wine), an appellation owned by only one winery * ''Monopole'' (album), a 2011 album by White Town * Monopole antenna, a radio antenna that replaces half of a dipole antenna with a ground plane at right-angles to the remaining half * Monopole, a tubular self-supporting telecommunications mast * ''The Monopole'', a bar in Plattsburgh, NY * Établissements Monopole, a French auto parts manufacturer, racing car builder and racing team. See also * Dipole, a particle with a north and south pole * Dyon, a particle with electric and magnetic charge * Instanton, a class of field solutions that includes monopoles * Monomial, a polynomial which has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexander Stepanovich Popov
Alexander Stepanovich Popov (sometimes spelled Popoff; russian: Алекса́ндр Степа́нович Попо́в; – ) was a Russian physicist, who was one of the first persons to invent a radio receiving device. declassified 8 January 2008 Popov's work as a teacher at a Russian naval school led him to explore high frequency electrical phenomena. On 7 May 1895, he presented a paper on a wireless lightning detector he had built that worked via using a coherer to detect radio noise from lightning strikes. This day is celebrated in the Russian Federation as Radio Day. In a 24 March 1896 demonstration, he transmitted radio signals 250 meters between different campus buildings in St. Petersburg. His work was based on that of another physicist – Oliver Lodge, and contemporaneous with the work of Guglielmo Marconi. Early life Born in the town of Krasnoturinsk, Sverdlovsk Oblast in the Urals as the son of a priest, he became interested in natural sciences when he was a ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heinrich Hertz
Heinrich Rudolf Hertz ( ; ; 22 February 1857 – 1 January 1894) was a German physicist who first conclusively proved the existence of the electromagnetic waves predicted by James Clerk Maxwell's Maxwell's equations, equations of electromagnetism. The unit of frequency, cycle per second, was named the "hertz" in his honor.IEC History . Iec.ch. Biography Heinrich Rudolf Hertz was born in 1857 in Hamburg, then a sovereign state of the German Confederation, into a prosperous and cultured Hanseatic (class), Hanseatic family. His father was Gustav Ferdinand Hertz. His mother was Anna Elisabeth Pfefferkorn. While studying at the Gelehrtenschule des Johanneums in Hamburg, Hertz showed an aptitude for sciences as well as languages, learning Arabic. He studied sciences and engineering in th ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ground Plane Antenna
A whip antenna is an antenna consisting of a straight flexible wire or rod. The bottom end of the whip is connected to the radio receiver or transmitter. A whip antenna is a form of monopole antenna. The antenna is designed to be flexible so that it does not break easily, and the name is derived from the whip-like motion that it exhibits when disturbed. Whip antennas for portable radios are often made of a series of interlocking telescoping metal tubes, so they can be retracted when not in use. Longer whips, made for mounting on vehicles and structures, are made of a flexible fiberglass rod around a wire core and can be up to long. The ideal length of the whip antenna is determined by the wavelength of the radio waves it is used with. The most common type is the ''quarter-wave whip'', which is approximately long, but they can be either longer or shorter by design, varying from compact electrically short antennas wavelength long, up to wavelength to improve direct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mast Radiator
Mast, MAST or MASt may refer to: Engineering * Mast (sailing), a vertical spar on a sailing ship * Flagmast, a pole for flying a flag * Guyed mast, a structure supported by guy-wires * Mooring mast, a structure for docking an airship * Radio masts and towers , towers that carry antennas * The primary support for a helicopter rotor * The main vertical structure of a forklift truck * Multi-axis shaker table, an automotive test system * Model for assessment of telemedicine, used to assess long-distance medical treatment Biology * Mast (botany), the edible parts of woody plants * Mast Arboretum, at Stephen F. Austin State University in Nacogdoches, Texas * Mast cell, involved in the allergy response * Mast., in botanical naming, the standard author abbreviation for Maxwell T. Masters * Two microtubule-associated serine/threonine-protein kinase enzymes: ** MAST1, an enzyme that in humans is encoded by the ''MAST1'' gene ** MAST2, an enzyme that in humans is encoded by the ''MAST ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inverted-F Antenna
An inverted-F antenna is a type of antenna used in wireless communication, mainly at UHF and microwave frequencies. It consists of a monopole antenna running parallel to a ground plane and grounded at one end. The antenna is fed from an intermediate point a distance from the grounded end. The design has two advantages over a simple monopole: the antenna is shorter and more compact, allowing it to be contained within the case of the mobile device, and it can be impedance matched to the feed circuit by the designer, allowing it to radiate power efficiently, without the need for extraneous matching components. The inverted-F antenna was first conceived in the 1950s as a bent-wire antenna. However, its most widespread use is as a planar inverted-F antenna (PIFA) in mobile wireless devices for its space saving properties. PIFAs can be printed using the microstrip format, a widely used technology that allows printed RF components to be manufactured as part of the same print ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
