Original poster: "Gav D" <gdingley@xxxxxxxxx>
Hi,
I think it is still an inverse square law, because although you are
focusing the power, it's density is still falling off with the square
of distance, as a perfect beam is impossible. The reflector (or
whatever focusing you are using) only increases the gain of the
radiating structure.
That said, I did try to record the inverse square law with a couple of
10GHz horn antennas, but the power appeared to roll-off at a rate of
1/r. Horn antennas have a gain of only 1.5 I think. I think my
numerical processing is to blame, 1/r^2 should hold.