In any electrical circuit the power loss is due to ohmic elements. A loss less transmission line therefore implies and . For a loss less transmission line hence we get
Propagation constant :
That is, and .
The charateristic impedance
The reflection coefficient at any point on the line is
The voltage and current expressions become
Let the reflection coefficient at the load end be written in the amplitude and phase form as
then we have
As we move towards the generator the phase becomes more negative and point P rotates clockwise
on the dotted circle. The radius of the circle is . Length of the vector OP gives the magnitude of the
quantity
and 
. For a loss less transmission line hence we get
and 
.
becomes more negative and point P rotates clockwise
on the dotted circle. The radius of the circle is 
. Length of the vector OP gives the magnitude of the
quantity 
