* '''Reactive near field:''' It is in immediate vicinity of antenna. The E-fields and H-fields here are 90° out of phaseand there distribution is very complex and it requires large computations to find that distribution. The distance from antenna is deciding factor in this region. It's boundary is given by [[File:Equation68.png]].* '''Radiative near field:''' Here too, the radiation pattern (radiated power vs direction) varies considerably with distance (away from antenna). The E-fields and H-fields are in phase here. It's boundary is given by [[File:Equation69.png]].* '''Far field:''' Here the radiation pattern is constant with respect to distance from antenna. Any antenna placed in far field of another antenna is not affected by its radiations. It extends to infinity.