HFSS: Field data export

I know there's a million threads about this topic but i browsed thru them and couldn't get any help.

I"d like to export numerical data of the field above and use it in matlab. I know i need to use the field calculator but i'm not sure how to create the grid points. If I select calculate grid points and give the coordinates, it won't accept same value for Zmin and Zmax, so basically it want's coordinates of a volume and not a surface.
Also is it possible to get the Phi and Theta components instead of x,y,z?
The surface is 16x16mm and centered in the point [0,0,10]

Thank you in advance

pls........help if any one know the solution

---------- Post added at 13:11 ---------- Previous post was at 13:09 ----------

when I try to do this....field calculatror need file with .pts extension.how to create that?