Eigen mode dispersion diagram

I would like to know the procedure for calcultaing the eigen mode dispersion diagram in HFSS for a split-ring resonator structure which doesnt have a ground plane..Please help.

post your project.

Hi
I think this is similar to extraction of dispersion diagram for a unit cell of an EBG structure. For help on this you can see www.Ansoft.com

used the same procedure as it was given in the example of mushroom ebg structure but without any success..For in one case,I have to please my unit cell in the middle of the airbox1 and not at the bottom...I am not quite able to modify the procedure for my structure..