..................................(7.50)
where
Since 
in the far field,
..................................(7.50)
where
Since in the far field,
for amplitude variation, we assume 
and for phase variation
w.r.to 1] | Fundamentals of Antennas and Radiating systems |
For |
, the loop may be treated as a point source. As shown in Fig 7.11, the elementary current element placed at 
has a vector orientation 
. For this current element the vector potential by equation (7.21)