S-parameters simulation

*I am simulating a circuit that includes a symbol created in the layout. (EM frequency setup 50MHz-350MHz).*

*In the circuit s-parameter setup: frequency range also is 50 MHz to 300MHz.*
*Type of simulation - linear.*

*However instead of my setup the ADS is performing an _adaptive_ simulation in the range of _0MHz to 10GHz_.* See below...

*What can be wrong?*

--------------------------------------------------------------------------------------------------
Status messages:

S-parameter simulation started
...initializing
...extracting layout
...expanding thick conductors
...analyzing ports
...reducing mesh
*Adaptive frequency sweep started*
*Simulation frequency [1] = 0 Hz*
...loading Green functions
...creating Basis sections
...allocating interaction matrix
...loading interaction matrix
...solving interaction matrix
...calculating S-parameters
*Simulation frequency [2] = 10 GHz*
...loading Green functions
...loading interaction matrix
...solving interaction matrix
...calculating S-parameters
*Adaptive: 0.0 % of frequency range covered*
*Simulation frequency [3] = 6.66667 GHz*
...loading Green functions
...loading interaction matrix
...solving interaction matrix
...calculating S-parameters
..............................................................................

Gigan on Aug 18, 2015 4:05 AM

Gigan on Aug 18, 2015 4:06 AM

It seems ADS remembers some old settings....

I solved the problem by using of a Sweep plan

The reason was not old settings. The reason is that keysight designed emModels to always use the frequency settings configured in the emModel, no matter what the frequency settings in your schematic are.

Sometimes that helps, and sometimes it hurts. If it was my product, I would have designed the emModel to retrieve the required frequencies from the "master document" that initiated the simulation, but Keysight designed it as described above: no frequency information is passed from the schematic to the emModel. The emModel uses whatever frequency plan you have set when creating the emModel. To change the frequency settings, modify the emModel settings directly, or modify the emSetup settings and re-create the emModel to use these new settings.

Thank you Volker, I understand.
I found that Sweep-plan also helps: It is not necessary go to emModel.


Question: Can you please explain how can I make VIAs visible in Symbol (created from the Layout) and in Circuit?

> I found that Sweep-plan also helps: It is not necessary go to emModel.

I don't know what you did, but from my understanding of ADS software architecture this can NOT work. The Sweep plan is just a different way of defining the schematic frequencies, and has no effect on emModel settings. The emModel settings including frequency range are defined in emStateFile.xml

But based on your post, I did a quick test. Result: same behaviour with sweep plan. emModel does not "see" what frequency you have set at schematic level, and uses the emModel frequency settings.

Did you mark "Use Sweep Plan" option in your SP1 set up?
Look (photos) on my results for: 50MHz - 350MHz:
It works!

附图/附件

SP1.jpg

SP2.jpg

> Did you mark "Use Sweep Plan" option in your SP1 set up?

Yes, as "Keysight Certfied Expert" I know the ADS basics ;-)

> Look (photos) on my results for: 50MHz - 350MHz:
> It works!

I don't get your point. Of course you get 50-350MHz results if you sweep the schematic from 50-350MHz. The sweep plan makes no difference then.

The point is what sweep the emModel uses, and that is ... as described above. If your schematic sweeps across frequencies that are not included in the emModel, you will see a warning in the schematic simulation log that data is extrapolated outside the emModel frequency range. Otherwise, if it is inside the frequency, you will see the normal emModel behaviour, including caching of already existing data.

It seems EMmodel was updated ...

> It seems EMmodel was updated ...

Wrong.

What you see is just the normal emModel data caching. If you re-simulate, the emModel does not need to repeat the EM simulation, because it caches the data. You can see cached data that if you descend into the emModel using the hierarchy button.

The frequency range is simulated as defined in the emModel, always. You repeated schematic level simulation and the EM data was already there, so you did not see another EM run. But the frequency settings from your schematic (S-parameter block or sweep plan) was never used for EM.

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