The electric field for the dipole is given as (only terms)
The total near field is given as
The Near field is minimum in the direction and maximum in the directions . However, along no direction the near field is zero.
The near field essentially stores the electromagnetic energy around the dipole but does not contribute to the power flow from the antenna.
Far Field
In the far field region only fields are the radiation fields.
The far field components of the electric and magnetic fields are given as
Important things to note about the far field (radiation field ) are,
(1)
The electric and magnetic fields are in time phase and they are in phase quadrature with the current. That is, these fields are proportional to the rate of change of current or acceleration of charges.
(2)
The ratio of the electric and magnetic field at every point in space is equal to the intrinsic impedance of the medium.
(3)
The wave travels in the r-direction, the electric field is in the -direction and the magnetic field is the -direction. That is, they are perpendicular to each other. These fields therefore represent transverse electromagnetic wave albeit spherical in nature. (See Fig.)
(4)
The fields are not uniform in all directions. The field strength is maximum along , and zero along . The Hertz dipole hence does not have any radiation along its axis.
terms) 
and maximum in the directions 
. However, along no direction the near field is zero. 
-direction and the magnetic field is the 
-direction. That is, they are perpendicular to each other. These fields therefore represent transverse electromagnetic wave albeit spherical in nature. (See Fig.) 
, and zero along 
. 
