TIA's Glossary of Telecommunication Terms

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antenna gain

The ratio of the power required at the input of a loss-free reference antenna to the power supplied to the input of the given antenna to produce, in a given direction, the same field strength at the same distance. Note 1: Antenna gain is usually expressed in dB. Note 2: Unless otherwise specified, the gain refers to the direction of maximum radiation. The gain may be considered for a specified polarization. Depending on the choice of the reference antenna, a distinction is made between:

• absolute or isotropic gain (G_i), when the reference antenna is an isotropic antenna isolated in space;
• gain relative to a half-wave dipole (G_d) when the reference antenna is a half-wave dipole isolated in space and with an equatorial plane that contains the given direction;
• gain relative to a short vertical antenna (G_r), when the reference antenna is a linear conductor, much shorter than one quarter of the wavelength, normal to the surface of a perfectly conducting plane which contains the given direction. [RR] (188) Synonyms gain of an antenna, power gain of an antenna.

Related Term

• antenna gain-to-noise-temperature (G/T)

• effective antenna gain contour (of a steerable satellite beam)

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