phase centre calculation cst

Hi all EM fans!
Does anyone have experience with phase center calculations in MWS?
I did some tests with theoretical results on rectangular horn and found good agreement in one plane. In second plane the results were different.
Who knows what the "Sigma" stands for? I mean when displaying the result there is phase center location and the Sigma value too.
What are your observations?
Thanks a lot
eirp

Hi,
the sigma is some kind of error measurement. You can specify a certain solid angle on a sphere for which the phase centre is calculated. The Phase Centre is the point, were the phase difference between all that points has its minimum.
The sigma is a value for the phase difference on all the points.
Large Sigma means: the phase varies quite lot on the sphere section.
Small sigma: the phase is pretty much identical on all points of the sphere section.
F.