In electromagnetics, directivity is a parameter of an antenna or optical system which measures the degree to which the radiation emitted is concentrated in a single direction. It is the ratio of the radiation intensity in a given direction from the antenna to the …

Directivity is a fundamental antenna parameter. It is a measure of how 'directional' an antenna's radiation pattern is. An antenna that radiates equally in all directions would have effectively zero directionality, and the directivity of this type of antenna would be 1 (or 0 dB).

2022年12月9日 · In electromagnetics, an antenna’s power gain or simply gain is a key performance number that combines the antenna’s directivity and electrical efficiency. As a transmitting antenna, the gain describes how well the antenna converts input power into radio waves headed in a specified direction.

The directivity of an antenna is the ratio of the power density S (radiant intensity per unit area) of the real antenna in its main direction to a hypothetical but non-existent isotropic radiator that would radiate uniformly in all directions.

2024年8月24日 · Directivity is ratio of power density in a specified direction to the power density averaged over all directions at the same distance from the antenna. Despite Equation \ref{m0203_eDirDef}, directivity does not depend on the distance from the antenna.

The ability of an antenna to radiate energy in a desired direction is characterized by its antenna directivity, D(f,T,I), which is the ratio of power actually transmitted in a particular direction to that which would be transmitted had the power P TR been radiated isotropically;

Directivity is a rough measure of an antenna. A more accurate measure is a radiation pattern plot. The radiation pattern plot is a graphical representation of intensity of radiation with respect to position throughout space. A radiation pattern plot may be a 3D plot or a pair of 2D plots.

To achieve a directivity that is significantly greater than unity, the antenna size needs to be much larger than the wavelength. This is usually achieved using a phased array of half-wave, or full-wave, antennas. Antennas can be used to receive, as well as emit, electromagnetic radiation.

In a transmitting antenna, gain describes the antenna’s ability to convert input power to radio waves sent in a specified direction. In a receiving antenna, gain describes the antenna’s ability to convert radio waves (incoming from a specified direction) into electrical power.

Directivity of antenna shows, how it able to radiates the energy in one or more specific direction. The radiation pattern of an antenna determines its directivity value. Then, Directivity D = maximum radiation intensity of a test antenna/radiation intensity of an isotropic antenna.