An isotropic antenna is an ideal antenna that radiates power with unit gain uniformly in all directions and is often used to reference antenna gains in wireless systems. There is no actual physical isotropic antenna; a close approximation is a stack of two pairs of crossed dipole antennas driven in quadrature. The radiation pattern for the isotropic antenna is a sphere with the antenna at its center. A yagi antenna Most simply, an antenna is an electronic component designed to send or receive radio waves. ... Isotropic means independent of direction. Isotropic radiation has the same intensity regardless of the direction of measurement, and an isotropic field exerts the same action regardless of how the test particle is oriented. ... A dipole antenna is an antenna with two driven elements. ...

Antenna gains are often specified in dBi, or decibels over isotropic. This is the power in the strongest direction divided by the power that would be transmitted by an isotropic antenna emitting the same total power. Although it is widely used as a measure of the loudness of sound, the decibel (dB) is more generally a measure of the ratio between two quantities, and can be used to express a wide variety of measurements in acoustics and electronics. ... Isotropic means independent of direction. Isotropic radiation has the same intensity regardless of the direction of measurement, and an isotropic field exerts the same action regardless of how the test particle is oriented. ...