FullWave: Periodic Boundary Conditions

Hi:

I'm trying to use the Periodic Boundary conditions for a 2D Photonic crystal with a hexagonal lattice. I have attached the unit cell that I chose. It basically consists of x(-Period,Period) and z(-PeriodZ,PeriodZ) in the x-z plane and PeriodZ is the period in the z-direction found by multiplying the period by the cosine of 30°.
When I run the simulation in FullWave, it freezes.
Is there something wrong with my unit cell definition (does it have to be bigger)?
Please can you'll suggest a method to incorporate PBC in FullWave. The PML boundaries work fine.

Thanks,
V

I think there are some examples in the examples directory for bandsolve. Also some explanation in the bandsolve manual. Well, these explanations are for the use of fullwave to calculate bandstructures. But I am sure they will be helpfull.