ISOTROPIC ANTENNA

There is some question about whether an Isotropic Antenna really does exist.  What the term "Isotropic Antenna" means is an antenna that transmits equally in all directions.  Such a thing is hard to achieve in real life.  However, whether they exist or not, one can mathematically determine how an isotropic antenna would work if it did exist.  And isotropic antennas do form a very important function.  They are used as standards by which one can determine how directional some other real life antennas are and what their antenna gains might be.  All antennas are therefore compared to the theoretical workings of an isotropic antenna.

The term antenna gain itself may seem odd and is explained on its own definition.  However, antennas do not really have gain in the same way an amplifier has gain.  Antenna gain refers to how concentrated the energy from an antenna can be if it just transmits in selected directions.  Since the energy is concentrated in those directions, the antenna will have less loss.  This is referred to as antenna gain.