The VNA does perform the vector summation
on its receive port, and will present the summation
as a decibel level compared to the transmit port,
if you select this presentation. On mine (HP8410B)
I only have the S parameter set, so I would choose
S21 display in dB. This level will show (assuming
S11 is better than -10dB) the gain of the send and
receive horns, together with the coupling loss.
All the textbooks I have looked at say the near
field energy falls off as the inverse cube of distance.
Thus going from one foot to two feet will decrease
the level by 9 dB (10*LOG[2 cubed]).
have to screen the area against reflections using
I am not familiar with Chu and
Semplak's paper/method, so I cannot comment. Hope
that helps some.
At bottom, life is all
Sucking in and blowing out.