Antenna simulation with CST MWS 5

[markus]

stability factor for time step

Hi,

Anyone CST Guru here?

I'm trying to simulate a chip antenna (constructed by meandering microstrip monopole on the FR4 base) located at the corner of circuit board (groudplane is removed just beneath the chip). However MWS tells me that calculation does not stay stable. Any good advices?

At the beginning I chose "planar antennas on substrate" -template. I tried to tune meshing options without any progress:

From global mesh properties I
- picked on Equilibrate mesh
- set Lines per wavelength and Lower mesh limit to value 20
- set Mesh line ratio limit to value 90 (Thats how I get one mesh layer in the thickness of the microstrip)
- picked off Merge fixpoints on thin PEC/lossy metal sheets
- set Refine at PEC/lossy metal value to 5

From parts local mesh properties I chose Optimize mesh for thin sheets for groundplane, feed microstip and radiatior microstrip. My boundary conditions were all open (add space)

Does these settings make any sense? MWS tells me to reduce values of PBA fill limit factor, or maximum stable time step factor. In another simulation I tried this but in did not help.

Will subgridding give some help? What does the option Always exclude the PEC material do?

Thanks!

 

[eirp]

pba meshfill limit

Hi,

Anyone CST Guru here?

I'm trying to simulate a chip antenna (constructed by meandering microstrip monopole on the FR4 base) located at the corner of circuit board (groudplane is removed just beneath the chip). However MWS tells me that calculation does not stay stable. Any good advices?

At the beginning I chose "planar antennas on substrate" -template. I tried to tune meshing options without any progress:

From global mesh properties I
- picked on Equilibrate mesh
- set Lines per wavelength and Lower mesh limit to value 20
- set Mesh line ratio limit to value 90 (Thats how I get one mesh layer in the thickness of the microstrip)
- picked off Merge fixpoints on thin PEC/lossy metal sheets
- set Refine at PEC/lossy metal value to 5

From parts local mesh properties I chose Optimize mesh for thin sheets for groundplane, feed microstip and radiatior microstrip. My boundary conditions were all open (add space)

Does these settings make any sense? MWS tells me to reduce values of PBA fill limit factor, or maximum stable time step factor. In another simulation I tried this but in did not help.

Will subgridding give some help? What does the option Always exclude the PEC material do?

Thanks!

Hi!

Hard to tell from your informations only.
However in such cases playing with PBA fill limit factor usually helps.
If you need help, post your project here (pack all the project dir)!

Kind regards

eirp

 

[divan]

antenna simulator pec

hello!
in MW@ 4 is such parameter as
"Stability factor for time step"
under trancient_solver/specials/solver .
try to find in v5 and play with and try Accuracy also , for first attemption at least.
And for chip antenna i think lambda/20 is too coarse, increase twice this value.
but better to place yours project here , mb even mod file .
regards

 

[elomatic]

Hi,
I had a problem with the stability in MWS4. I used a parallel processor and always had problems with the stability. I could solve the problem when I chosed to use only one processor.
...who knows why...

ciao