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| | AntennaA length of wire or similar that radiates (such as a transmitting antenna) or absorbs (such as a radio antenna) radio waves. Also known as an Aerial. Adcock AerialAn Adcock aerial is a radio aerial system consisting of two vertical open-spaced dipoles. Beverage AntennaA horizontal, long-wire antenna designed for reception and transmission of low-frequency, vertically polarized ground waves. Also known as a Wave Antenna. Bidirectional ArrayAn array that radiates in opposite directions along the line of maximum radiation. Broadside ArrayAn array in which the direction of maximum radiation is perpendicular to the plane containing the elements. Centre Feed MethodConnecting the center of an antenna to a transmission line which is then connected to the output stage of the transmitter. Colinear ArrayAn array with all the elements in a straight line. Maximum radiation is perpendicular to the axis of the elements. Combination ArrayAn array system that uses the characteristics of more than one array. Corner Reflector AntennaA half-wave antenna with a reflector consisting of two flat metal surfaces meeting at an angle behind the radiator. CounterpoiseA network of wire connected to a quarter-wave antenna at one end. The network provides the equivalent of an additional one-fourth wavelength. Directional AntennaAn antenna that radiates most effectively in only one direction. Driven ElementThe element of an antenna connected directly to the transmission line End Fire ArrayAn array in which the direction of radiation is parallel to the axis of the array. Folded DipoleAn ordinary half-wave antenna that has one or more additional conductors connected across the ends parallel to each other. Four Element ArrayAn antenna array with three parasitic elements and one driven element. Ground Plane AntennaA type of antenna that uses a ground plane as a simulated ground to produce low-angle radiation. Half Wave Dipole AntennaAn antenna, consisting of two rods in a single line, that radiates electromagnetic energy. Hertz AntennaA half-wave antenna that is installed some distance above ground and positioned either vertically or horizontally. Horn RadiatorA tapered, tubular or rectangular microwave antenna that is widest at the open end. Long Wire AntennaAn antenna that is a wavelength or more long at its operating frequency. Marconi AntennaA quarter-wave antenna that is operated with one end grounded and is positioned perpendicular to the earth. Multi Element ArrayAn array that consists of one or more arrays and is classified as to directivity. Multi Element Parasitic ArrayAn array that contains two or more parasitic elements and a driven element. Omnidirectional AntennaAn antenna that radiates and receives equally in all directions. Parasitic ArrayAn antenna array containing one or more elements not connected to the transmission line. Parasitic ElementThe passive element of an antenna array that is connected to neither the transmission line nor the driven element. Rhombic AntennaA diamond-shaped antenna used widely for long-distance, high-frequency transmission and reception. Three Element ArrayAn array with two parasitic elements (reflector and director) and a driven element. Top Hat AntennaAn antenna that is centre-fed and capacitively loaded. TriaticA special type of monopole antenna array. Turnstile AntennaA type of antenna used in vhf communications that is omnidirectional and consists of two horizontal half-wave antennas mounted at right angles to each other in the horizontal plane. Unidirectional ArrayAn antenna array that radiates in only one general direction. V AntennaA bidirectional antenna, shaped like a V, which is widely used for communications. Wave AntennaAlso known as a Beverage Antenna. Yagi AntennaA directional antenna consisting of a rod pointed in the direction of the transmission/reception and several cross bars.
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| Science & Engineering Encyclopaedia Version 2.4 © 2001-2010 Dirac Delta Consultants Limited | ||||||