Lecture 25 : Solution of Wave Equation in Homogeneous Unbound medium
Uniform Plane Wave(contd.)
Substituting for from the above equation in the Maxwell's equation we have
We can note that the ratio of the electric field and the magnetic field for a wave travelling in direction is
and that travelling in direction is
Let us define a quantity called the intrinsic impedance of the medium as
The intrinsic impedance for a medium serves the same
purpose as the characteristic impedance serves for a transmission line. The intrinsic impedance is a property of the medium. For the free-space (vacuum),
The intrinsic impedance of the free-space, is
For any other medium
Where and are the relative permeability and relative permittivity of the medium respectively, and the
intrinsic impedance is
The uniform plane wave has following properties
, and direction of the wave are perpendicular to each other. Infact they form right handed orthogonal
coordinate system when taken in that sequence. This wave, is therefore a 'Transvers Electromagnetic Wave'
(TEM) Wave.
The ratio for the wave is equal to the intrinsic impedance of the medicem, .
The Vector Magnetic Field for a uniform plane wave is completely defined if the Vector Electric Field and the direction
of wave is known along with the medium parameters.
We therefore discuss only the behaviour of the electric field of a plane wave.
,
and direction of the wave are perpendicular to each other. Infact they form right handed orthogonal
coordinate system when taken in that sequence. This wave, is therefore a 'Transvers Electromagnetic Wave'
(TEM) Wave. 
for the wave is equal to the intrinsic impedance of the medicem, 
.
