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S-para simulation in Momentum. Call for help!

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wireless man

wireless man

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momentum s-para

When I do S-para simulation, the system presents teh following warning.
9_1229001928.jpg

If I click Yes, the simulation will keep the same even after several hours.

Does anybody can tell me the reason and solution.
ps: The substrate has been difined. Thks.
 

Did you set the substrate values? There are some things you have to
do before you simulate in Momentum. If you can, call Agilent's ADS help
line. They can walk you through this process. Or use the help files and
search Momentum Simulation.

Good luck
 

    wireless man

    wireless man

    Points: 2
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Its not a warning. It is information box. Momentum must calculate the substrate. You may have a very large frequency range, very small frequency steps or many substrate layers. To start, try solving at only one frequency.
 

    wireless man

    wireless man

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Momentum needs to calculate substrate information for the first time, and then you can draw any structure and perform any number of simulations you want.

Also, don't set too high frequencies. If you work at 1 GHz, don't simulate the substrate to 100 GHz.
 

    wireless man

    wireless man

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if you have a legal license, check the knowledge center: **broken link removed**
 

    wireless man

    wireless man

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This is good observation.
If you have simple structure let say microstrip transmiission lines then the substrate calculation is simple and you will come out quickly.
But if the structure is complex let say 16 layers of LTCC or 20 layers of different dielectric stackup then the momentum takes sufficient amount of time ( in tens of minutes to calculate the substrate function.
Just leave it and wait for completion of task.
Do not worry about that the system is not doing any thing. You can verify the same using the task manager
 

    wireless man

    wireless man

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kspalla said:
This is good observation.
If you have simple structure let say microstrip transmiission lines then the substrate calculation is simple and you will come out quickly.
But if the structure is complex let say 16 layers of LTCC or 20 layers of different dielectric stackup then the momentum takes sufficient amount of time ( in tens of minutes to calculate the substrate function.
Just leave it and wait for completion of task.
Do not worry about that the system is not doing any thing. You can verify the same using the task manager
Click to expand...

The substrate is built in terms of 0.13 um CMOS process, that means 8 metal layers and over 20 dielectrical layers. I admit that the substrate is so complex, but 5 hours later, the simulation still doesn't finish. The message box shows following:


WARNING :
Failed to converge, continuing ...

Consequence : - database may not be accurate for frequencies
close to 0.166131 GHz.
WARNING :
Failed to converge, continuing ...

Consequence : - database may not be accurate for frequencies
close to 0.166158 GHz.
WARNING :
Failed to converge, continuing ...

Consequence : - database may not be accurate for frequencies
close to 0.144913 GHz.
WARNING :
Failed to converge, continuing ...

Consequence : - database may not be accurate for frequencies
close to 0.145339 GHz.
WARNING :
Failed to converge, continuing ...

Consequence : - database may not be accurate for frequencies
close to 0.146747 GHz.

Status / Summary

------------ Momentum Simulation -----------------

Version: Momentum MomEngine 7.0 (*) 2008.500 Jan 22 2008
Simulation mode: MW
Design: C75_W6_S2_N4_30K

Simulation started on : Fri Dec 12 11:09:26 2008

Substrate calculation started

So, what's the matter? Thank you all.
ps: What I am simulating is a 4-turn inductor which is imported from GDSII file.
 

Did you define your substrate file correctly?
 

    wireless man

    wireless man

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Is it has problem with port assignment?
To know better please share the simulation summary with us.
Just a section of summary is not enough to find the cause.
 

    wireless man

    wireless man

    Points: 2
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