hfss ebg simulation

I am trying to use HFSS for simulating a Sievenpiper type of high impedance surface. I want to obtain the dispersion diagram.
1)how far away I should put the PML from the object (top patch). does it still need lamda/4 requirement as radiation boundary? what is the criterion for PML setting: (a) PML uniform layer thickness (b) minimus radiating distance
2)is it necessary for the PBC boundaries to cover the sides of the PML material on the top as well?
3)when I use Eigensolver, I get both real (almost real) eigen frequencies and complex eigen frequencies. How can I get the diesperion diagram out of this? I mean, what are those complex eigenfrequencies?

I try to simulate the structure of Sievenpiper paper:IEEE Tran. on MTT V47(11): 2059-2074. the structur parameters as page 2065, Fig.9,but I can't get the same answer as Fig. 10. I attach my design file, if possible could anyone tell me what is wrong for my design? If you get the right answer, could you send me the design file.
Thanks a lot!

design file

There's an excellent tutorial at hSSp://www.emtalk.com/tut_3.htm, for HFSS v10.

Enjoy it,

Pere

thanks

In the setup,check this box:solve for real frequensies only.It is no need to get complex frequensies.

Hi,

I've seen your HFSS file and I was hoping that you have some kind of tutorial of how to build and simulate EBG on HFSS, in order to find the frequency band gap and the reflection phase. Do you have that kind of document?

thanks,

PS: I'm a newer in HFSS, I'm sorry i can't help you with the warnings......

Thank you very much!