Isotropic antenna
From Wikipedia, the free encyclopedia
An isotropic antenna is an ideal antenna that radiates power with unit gain uniformly in all directions and is often used as a reference for 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.
Antenna gains are often specified in dBi, or decibels over isotropic. This is the power in the strongest direction relative to the power that would be transmitted by an isotropic antenna emitting the same total power.
