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The monopole antenna was invented in 1895 by radio pioneer Guglielmo Marconi; for this reason it is sometimes called the Marconi antenna. [4] [5] [6] The load impedance of the quarter-wave monopole is half that of the dipole antenna or 37.5 ohms. Common types of monopole antenna are
The main antenna used for these devices is the printed inverted F antenna (PIFA) consisting of a monopole antenna bent in an L shape, fabricated of copper foil on the printed circuit board inside the device. Small sleeve dipoles or quarter-wave monopoles are also used. The patch antenna is another common type, often integrated into the skin of ...
The rubber ducky antenna (or rubber duck aerial) is an electrically short monopole antenna, invented by Richard B. Johnson, that functions somewhat like a base-loaded whip antenna. It consists of a springy wire in the shape of a narrow helix , sealed in a rubber or plastic jacket to protect the antenna. [ 1 ]
It is shaped like the Greek letter Π or an upside-down capital letter U, and is the loop antenna analog of a ground-mounted monopole antenna. Similar to how a vertical monopole uses its ground system to produce a "phantom" image of the rest of a dipole, the missing lower half of the half-loop is replaced by its ground-plane image. If shaped ...
The folded unipole antenna is a type of monopole mast radiator antenna used as a transmitting antenna mainly in the medium wave band for AM radio broadcasting stations. It consists of a vertical metal rod or mast mounted over and connected at its base to a grounding system consisting of buried wires.
It is the most efficient antenna design found so far for this frequency range, achieving efficiencies of 70-80% where other VLF antenna designs have efficiency of 15-30% due to the low radiation resistance of the very electrically short monopole. [8] The antenna was invented by Boynton Hagaman of Development Engineering Co. (DECO) and first ...
The name comes from its resemblance to an inverted letter "L" (Γ). The T-antenna is an omnidirectional antenna, radiating equal radio power in all azimuthal directions, while the inverted-L is a weakly directional antenna, with maximum radio power radiated in the direction of the top load wire, off the end with the feeder attached.
The discone antenna has a useful frequency range of at least 10 to 1. [2] [3] When employed as a transmitting antenna, a properly constructed discone is just as efficient as an antenna designed for a more limited frequency range. The extra bandwidth comes from the controlled taper and large termination radius of the cone.