MONOPOLE ANTENNA

MONOPOLE ANTENNA

A monopole antenna is a type of radio antenna consisting of a straight rod-shaped conductor, placed  perpendicularly over some type of conductive surface, called a ground plane.

 The monopole antenna was invented in 1895 by  Guglielmo Marconi; for this reason it is sometimes called the Marconi antenna. Common types of monopole antenna are the whip, rubber ducky, helical, random wire, umbrella, inverted-L and T-antenna, inverted-F, mast radiator, and ground plane antennas.The monopole antenna is an common antenna that is often used on vehicles and other areas were a large conductive flat area is present (“ground plane”). The standard monopole antenna measures 1/4 wavelength in height (λ/4); however, this antenna must be placed on to a large conductive surface to function properly.

The length of the antenna is determined by the wavelength of the radio waves.  The most common form is the quarter-wave monopole, in which the antenna is approximately one quarter of the wavelength of the radio waves. A monopole antenna has an omnidirectional radiation pattern: it radiates with equal power in all azimuthal directions which means horizontal angle measured clockwise from any fixed reference perpendicular to the antenna

POLE BROADCASTING ANTENNA

While using radio broadcasting, the radio frequency power from the broadcasting transmitter is fed across the base insulator between the tower and a ground system. The ideal ground system for AM broadcasters comprises at least 120 buried copper or phosphor bronze radial wires at least one-quarter wavelength long and a ground-screen. All the ground system components are bonded together, usually by welding, brazing or using coin silver solder to help reduce corrosion. Monopole antennas  uses guy-wires for support which is named as masts in some countries. In the United States, the term “mast” is generally used to describe a pipe supporting a smaller antenna, so both self-supporting and guy-wire supported radio antennas are simply called monopoles if they stand alone. If multiple monopole antennas are used in order to control the direction of radio frequency (RF) propagation, they are called directional antenna arrays.