CST frequency range problem

Hi all,
When i simulate my design in CST in the frequency range 2-6GHz, i m getting good S11 result. When i change the range to 0-6GHz, i get different S11 values at the same frequency! can anyone please explain why is this happening?
Thanks

I think the mesh is calculated at the middle frequency of the frequency range. This 4Ghz in first case and 3GHz in the second one, thus you have a different mesh which could lead to different solutions. However this should not happen, so could try to increase the mesh density.
And you could search in the forum - this topic hast some threads. For example:
https://www.edaboard.com/thread155108.html
https://www.edaboard.com/thread139165.html

thanks a lot for the reply ..problem has been solved.