S parameter problem in CST microwave studio 2009

來源：edatop 更新時間：2024-08-23 閱讀：

Dear all,
I am trying to design a microstrip antenna using metamaterials. The problem is S-parameter found in the simulation does not go below -10db even after using only air,FR4 insted of metamaterial as substrates. I simulated the same thing at HFSS which give S-parameter below -10db. The expected result of S-parameter always match with HFSS result but not with CST. Is there any way i can solve my problem? please tell me how to obtain the S-parameter properly. I think my simulation process has errors but i can't figure the fault in it. I need urgent help. Mailing me is also appreciated.
Thank you all.

can you attach your simulation file, please?

Here is the file and also the design . the design follows the graph of page 6 figure-9(a(2)i.e Lr=1.1 almost) of pdf.

Hi all I am having similar problems in this . i am trying to design a planar device , i am following strictly to the tutorial in CST Microwave Studio 2009 . However i faced the problem of having my S-parameter phase shift being too big when i complied them. If you need any additional information , i will be happy to reply .

first picture contains my work , the second picture belongs to the tutorial

The first picture shows that you have two warnings, what are they?
Have you done all steps as in the tutorial?

Hi flanello , i followed all the steps and checked what i have done with the pictures . I started the simulations and run in -30db , it ended with 1 warnings and arg(S) in error , later i did the 2nd part and run in -50db with adaptive meshing , and ended with 2 warnings and arg(S) . I did not have problems with the rest , also i do not know how to check out what the warnings are. Would it help if i provided the details of the solver logfile?
Starting adaptive port meshing.
--------------------------------------------------------------------------------
Mode calculation for port 1:
--------------------------------------------------------------------------------
Build version: 2009.0 Release from 2008-10-14 (change 82794)
Solver module: Port Modes (Win 32)
================================================== ====================
Port mode calculation
================================================== ====================
--------------------------------------------------------------------------------
Units settings:
Dimensions: mil
Frequency: GHz
Time: ns
--------------------------------------------------------------------------------
Mesh statistics:
Hexahedral mesh type: PBA
Parallelization type: none
Mesh summary:
< 0.5 :0.0 %
< 0.25 :0.0 %
< 0.1 :0.0 %
< 0.05 :0.0 %
< 0.02 :0.0 %
Minimal filling: 92.346 %
--------------------------------------------------------------------------------
Boundary conditions:
YZsymmetry: none
XZsymmetry: none
XYsymmetry: none
Xmin: electric
Xmax: electric
Ymin: electric
Ymax: electric
Zmin: electric
Zmax: electric
--------------------------------------------------------------------------------
Frequency settings:
Fmin: 6
Fmax: 17
Nfsteps: 1001
--------------------------------------------------------------------------------
Waveguide boundaries:
--------------------------------------------------------------------------------
Port: 1
--------------------------------------------------------------------------------
----------------------------------------------------------------------------
Port Mode Type Z-Wave Z-Wave-Sigma Z-Line F-Cutoff
1 1 QTEM 180 0.0029 47 ---
----------------------------------------------------------------------------
--------------------------------------------------------------------------------
Solver Statistics:
Number of meshcells: 2728
Mesh generation time: 3 s
--------------------------------------------------------------------------------
Total simulation time: 6 s
--------------------------------------------------------------------------------
Pass 1 successfully completed.
Build version: 2009.0 Release from 2008-10-14 (change 82794)
Solver module: Port Modes (Win 32)
================================================== ====================
Port mode calculation
================================================== ====================
--------------------------------------------------------------------------------
Units settings:
Dimensions: mil
Frequency: GHz
Time: ns
--------------------------------------------------------------------------------
Mesh statistics:
Hexahedral mesh type: PBA
Parallelization type: none
Mesh summary:
< 0.5 :0.0 %
< 0.25 :0.0 %
< 0.1 :0.0 %
< 0.05 :0.0 %
< 0.02 :0.0 %
Minimal filling: 84.693 %
--------------------------------------------------------------------------------
Boundary conditions:
YZsymmetry: none
XZsymmetry: none
XYsymmetry: none
Xmin: electric
Xmax: electric
Ymin: electric
Ymax: electric
Zmin: electric
Zmax: electric
--------------------------------------------------------------------------------
Frequency settings:
Fmin: 6
Fmax: 17
Nfsteps: 1001
--------------------------------------------------------------------------------
Waveguide boundaries:
--------------------------------------------------------------------------------
Port: 1
--------------------------------------------------------------------------------
----------------------------------------------------------------------------
Port Mode Type Z-Wave Z-Wave-Sigma Z-Line F-Cutoff
1 1 QTEM 182 0.000569 47.2 ---
----------------------------------------------------------------------------
--------------------------------------------------------------------------------
Solver Statistics:
Number of meshcells: 5548
Mesh generation time: 2 s
--------------------------------------------------------------------------------
Total simulation time: 6 s
--------------------------------------------------------------------------------
Pass 2 successfully completed. Delta (Line Imp.): 0.261064%
Build version: 2009.0 Release from 2008-10-14 (change 82794)
Solver module: Port Modes (Win 32)
================================================== ====================
Port mode calculation
================================================== ====================
--------------------------------------------------------------------------------
Units settings:
Dimensions: mil
Frequency: GHz
Time: ns
--------------------------------------------------------------------------------
Mesh statistics:
Hexahedral mesh type: PBA
Parallelization type: none
Mesh summary:
< 0.5 :0.0 %
< 0.25 :0.0 %
< 0.1 :0.0 %
< 0.05 :0.0 %
< 0.02 :0.0 %
Minimal filling: 69.385 %
--------------------------------------------------------------------------------
Boundary conditions:
YZsymmetry: none
XZsymmetry: none
XYsymmetry: none
Xmin: electric
Xmax: electric
Ymin: electric
Ymax: electric
Zmin: electric
Zmax: electric
--------------------------------------------------------------------------------
Frequency settings:
Fmin: 6
Fmax: 17
Nfsteps: 1001
--------------------------------------------------------------------------------
Waveguide boundaries:
--------------------------------------------------------------------------------
Port: 1
--------------------------------------------------------------------------------
----------------------------------------------------------------------------
Port Mode Type Z-Wave Z-Wave-Sigma Z-Line F-Cutoff
1 1 QTEM 185 0.00959 47.2 ---
----------------------------------------------------------------------------
--------------------------------------------------------------------------------
Solver Statistics:
Number of meshcells: 11346
Mesh generation time: 2 s
--------------------------------------------------------------------------------
Total simulation time: 17 s
--------------------------------------------------------------------------------
Pass 3 successfully completed. Delta (Line Imp.): 0.062177%
Mode calculation for port 2:
--------------------------------------------------------------------------------
Build version: 2009.0 Release from 2008-10-14 (change 82794)
Solver module: Port Modes (Win 32)
================================================== ====================
Port mode calculation
================================================== ====================
--------------------------------------------------------------------------------
Units settings:
Dimensions: mil
Frequency: GHz
Time: ns
--------------------------------------------------------------------------------
Mesh statistics:
Hexahedral mesh type: PBA
Parallelization type: none
Mesh summary:
< 0.5 :0.0 %
< 0.25 :0.0 %
< 0.1 :0.0 %
< 0.05 :0.0 %
< 0.02 :0.0 %
Minimal filling: 92.346 %
--------------------------------------------------------------------------------
Boundary conditions:
YZsymmetry: none
XZsymmetry: none
XYsymmetry: none
Xmin: electric
Xmax: electric
Ymin: electric
Ymax: electric
Zmin: electric
Zmax: electric
--------------------------------------------------------------------------------
Frequency settings:
Fmin: 6
Fmax: 17
Nfsteps: 1001
--------------------------------------------------------------------------------
Waveguide boundaries:
--------------------------------------------------------------------------------
Port: 2
--------------------------------------------------------------------------------
----------------------------------------------------------------------------
Port Mode Type Z-Wave Z-Wave-Sigma Z-Line F-Cutoff
2 1 QTEM 180 0.0029 47 ---
----------------------------------------------------------------------------
--------------------------------------------------------------------------------
Solver Statistics:
Number of meshcells: 2728
Mesh generation time: 2 s
--------------------------------------------------------------------------------
Total simulation time: 6 s
--------------------------------------------------------------------------------
Pass 1 successfully completed.
Build version: 2009.0 Release from 2008-10-14 (change 82794)
Solver module: Port Modes (Win 32)
================================================== ====================
Port mode calculation
================================================== ====================
--------------------------------------------------------------------------------
Units settings:
Dimensions: mil
Frequency: GHz
Time: ns
--------------------------------------------------------------------------------
Mesh statistics:
Hexahedral mesh type: PBA
Parallelization type: none
Mesh summary:
< 0.5 :0.0 %
< 0.25 :0.0 %
< 0.1 :0.0 %
< 0.05 :0.0 %
< 0.02 :0.0 %
Minimal filling: 84.693 %
--------------------------------------------------------------------------------
Boundary conditions:
YZsymmetry: none
XZsymmetry: none
XYsymmetry: none
Xmin: electric
Xmax: electric
Ymin: electric
Ymax: electric
Zmin: electric
Zmax: electric
--------------------------------------------------------------------------------
Frequency settings:
Fmin: 6
Fmax: 17
Nfsteps: 1001
--------------------------------------------------------------------------------
Waveguide boundaries:
--------------------------------------------------------------------------------
Port: 2
--------------------------------------------------------------------------------
----------------------------------------------------------------------------
Port Mode Type Z-Wave Z-Wave-Sigma Z-Line F-Cutoff
2 1 QTEM 182 0.000569 47.2 ---
----------------------------------------------------------------------------
--------------------------------------------------------------------------------
Solver Statistics:
Number of meshcells: 5548
Mesh generation time: 2 s
--------------------------------------------------------------------------------
Total simulation time: 6 s
--------------------------------------------------------------------------------
Pass 2 successfully completed. Delta (Line Imp.): 0.261064%
Build version: 2009.0 Release from 2008-10-14 (change 82794)
Solver module: Port Modes (Win 32)
================================================== ====================
Port mode calculation
================================================== ====================
--------------------------------------------------------------------------------
Units settings:
Dimensions: mil
Frequency: GHz
Time: ns
--------------------------------------------------------------------------------
Mesh statistics:
Hexahedral mesh type: PBA
Parallelization type: none
Mesh summary:
< 0.5 :0.0 %
< 0.25 :0.0 %
< 0.1 :0.0 %
< 0.05 :0.0 %
< 0.02 :0.0 %
Minimal filling: 69.385 %
--------------------------------------------------------------------------------
Boundary conditions:
YZsymmetry: none
XZsymmetry: none
XYsymmetry: none
Xmin: electric
Xmax: electric
Ymin: electric
Ymax: electric
Zmin: electric
Zmax: electric
--------------------------------------------------------------------------------
Frequency settings:
Fmin: 6
Fmax: 17
Nfsteps: 1001
--------------------------------------------------------------------------------
Waveguide boundaries:
--------------------------------------------------------------------------------
Port: 2
--------------------------------------------------------------------------------
----------------------------------------------------------------------------
Port Mode Type Z-Wave Z-Wave-Sigma Z-Line F-Cutoff
2 1 QTEM 185 0.00959 47.2 ---
----------------------------------------------------------------------------
--------------------------------------------------------------------------------
Solver Statistics:
Number of meshcells: 11346
Mesh generation time: 3 s
--------------------------------------------------------------------------------
Total simulation time: 17 s
--------------------------------------------------------------------------------
Pass 3 successfully completed. Delta (Line Imp.): 0.062177%
Adaptive port meshing finished.
--------------------------------------------------------------------------------
Build version: 2009.0 Release from 2008-10-14 (change 82794)
Solver module: Time Domain: S-Parameter (Win 32)
================================================== ====================
Solver cycle: 1
================================================== ====================
Stimulation at port 1 (mode 1)
--------------------------------------------------------------------------------
Units settings:
Dimensions: mil
Frequency: GHz
Time: ns
--------------------------------------------------------------------------------
Mesh statistics:
Hexahedral mesh type: PBA
Parallelization type: none
Mesh summary:
< 0.5 :0.4 %
< 0.25 :0.2 %
< 0.1 :0.1 %
< 0.05 :0.0 %
< 0.02 :0.0 %
Minimal filling: 3.045 %
--------------------------------------------------------------------------------
Field update statistics:
Number of components in total: 476648
Subcycling state: Automatically deactivated
--------------------------------------------------------------------------------
Boundary conditions:
YZsymmetry: none
XZsymmetry: none
XYsymmetry: none
Xmin: electric
Xmax: electric
Ymin: electric
Ymax: electric
Zmin: electric
Zmax: electric
--------------------------------------------------------------------------------
Frequency settings:
Fmin: 6
Fmax: 17
Nfsteps: 1001
--------------------------------------------------------------------------------
Waveguide boundaries:
--------------------------------------------------------------------------------
Port: 1
--------------------------------------------------------------------------------
----------------------------------------------------------------------------
Port Mode Type Z-Wave Z-Wave-Sigma Z-Line F-Cutoff
1 1 QTEM 180 0.0029 47.2 ---
----------------------------------------------------------------------------
--------------------------------------------------------------------------------
Port: 2
--------------------------------------------------------------------------------
----------------------------------------------------------------------------
Port Mode Type Z-Wave Z-Wave-Sigma Z-Line F-Cutoff
2 1 QTEM 180 0.0029 47.2 ---
----------------------------------------------------------------------------
--------------------------------------------------------------------------------
Steady state energy criterion met, solver stopped.
--------------------------------------------------------------------------------
----------------------------------------------------------------------------
Peak memory used (kB) Free physical memory (kB)
Physical Virtual At begin Minimum
----------------------------------------------------------------------------
Matrices calc. 53976 105788 1716760 1677272
Solver run total 55548 150268 1739044 1682024
----------------------------------------------------------------------------
Solver Statistics:
Computername: WDL-89FK72S
Number of meshcells: 76384
Excitation duration: 6.462816e-001 ns
Calculation time for excitation: 29 s
Number of calculated pulse widths: 1.00654
Steady state accuracy limit: -50 dB
Simulated number of time steps: 6897
Maximum number of time steps: 342609
Time step width:
without subcycles: 9.431748e-005 ns
used: 9.431748e-005 ns
Number of threads used: 2
Matrix calculation time: 6 s
Solver time: 29 s
------------
Total time: 35 s
--------------------------------------------------------------------------------
Total simulation time: 36 s

What device are you trying to simulate?
When you want to simulate an antenna you should check your background material and your boundary conditions, since at the moment you have electric side walls. For an antenna you need open or open add space.

Hi thanks for the reply . I am trying to simulate a planar device now , i am just trying to follow the tutorial . I had not done the simulation of the antenna . I did not do the boundary conditions as the tutorial did not indicate it necessary. I will try to add it in when i reach my school lab tomorrow.

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