This is the first time I've met this situation in CST

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Hi, everybody
Nowaday, I am studying the dual-band antenna.
But, after setting the simulation conditions, I got the very strange results as in the following pictures:

I think my setting in the calculation domain and the meshing properties have some mistakes! But I don"t know how to correct it!
Maybe it also relative to the port size and the stability factor/full fill limit factor!
Have anyone been in this situation?
the simulation time only spent about 20 minutes, please study together!

Hi KhangKhang,
your simulation became unstable. Happens from time to time. There could be several reasons for this.
If you use a waveguide port, try to switch on "add electric shielding around port" in the solver special settings..
If this does not help you can try to reduce the time step factor and the PBA fill limit.
Usually this does the job...
F.

In the HELP , they notice that these factor are very special factor, and we should not change it!
Anyway, I am following ur way and wait for the results!
Regards!

Yeah, the results seem to be good, and my simulation became stable!
Thanks a lot, RF!

But which suggestion did you finally take from RFSimulator to get the pleasant result?

hi khangKhang,
Could you please answer my last reply?

Sorry DB, I am so busy to answer ur reply!
First, I tried to reduce the time step factor and PBA fill limit, according ur suggestion and the warning from the system....however, it did not change any thing...I mean the simulation was still unstable.
Second, I tried with the option :"Add electric shield around port"...yeah, the simulation became stable and reached the stable state.
But, when I am designing my structure with modifying many things, I had tried to un-choose the mentioned-above option ("add electric..."), the simulation have become stable.
I don't know why and I am confusing about the previous unstable phenominal.