CST - Meshing doubt

Hi all,
I have a basic doubt. In CST MWS - 5 , when meshing a structure , we specify the meshing density as lines per wavelength in the "Mesh Properties" dialog box. Here what does wavelength mean ? Is it free space wavelength of the highest frequency of simulation or is it the wavelength in the material with highest dielectric constant ? Thanks for your help.
-svarun

Hi
MWS takes the dielectric into account. 10 lines per wavelength means minimum of ten lines at the shortest wavelength inside a dielectric
F.