Isotropic Radiator

an imaginary antenna emitting electromagnetic energy of equal intensity in all directions. It has a circular directivity pattern in any plane. The isotropic radiator is used in antenna technology as a standard for the comparative evaluation of the directional characteristics of various antennas, particularly in determining the front-to-rear factor. A great deal of attention is being devoted to the design of antennas whose directional properties are close to those of an isotropic radiator. In particular, such antennas are required for use on artificial earth satellites that are unstabilized in space. Antennas of that type make possible the maintenance of communications with the satellite when it changes its position in space.