Musuroom_EBG_cell_in_CST

Hello All,
I am trying to simulate a unit cell of mushroom EBG in CST.
Why I have got too much ripple in the S11 plot with some values greater than one.
is the setting of my cst file correct?
Please help

any one?..................................

Hi,
Firstly, I have no experience on EBG simulation. However, you should note the following comments:
1. In your cst model, you didn't discretized your geometry. In the "Mesh-Global mesh properties-Lines per wavelength", and the local mesh properties of PEC and Rogers materials should be set up.
2. I don't know the reason why you set only one port. Generally, 2 ports are needed.
3. For boundary conditions, PEC+PMC for periodic boundary is right. So why use PEC for Zmin? I think it should be open. And a proper value for the distance between the port and the side of the cell should be used.
I hope the above comments are useful,
Zhang

I am still waiting for someone to hep me

Hi Mustafa,
Try to use AR filter option and use a great number of pulses in Steady state menu under specials for Transient solver.
good work

I know this is a very old post, but just for reference in this thread here's my suggestion.
Ripples can be due to accuracy setting in CST transient solver, if you set your accuracy to -40 or -50 you'll get better results (excitation signal will decay better causing less problem when doing Fourier transform)
Another solution might be looking at your mesh settings for increased accuracy (adaptive mesh refinement).