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Need help with ADS momentum Co-simulation

Mabrok

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Hi,
I am doing power amplifier design, and have to do momentum Co-simulation. I created EM model from the layout, then I opened from the schematic window as shown in the attached file. However, when I run the simulation it doesn't show any performance. It looks like there is something wrong. How about the DC ground circled in the photo? Is that correct? thanks in advancedADS co-simulation.jpg
 
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volker@muehlhaus

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It is difficult to see what you did there.

Is that a via model?
And did you map the "hole" layer in your Momentum stackup, so that the via element creates a ground connection in the EM model?
Do you see the vias in the 3D EM preview?

PS: When you create the look-alike symbol, you can specify a size or scaling factor, so that it has a more useful size compared to circuit elements.
 

Mabrok

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It is difficult to see what you did there.

Is that a via model?
And did you map the "hole" layer in your Momentum stackup, so that the via element creates a ground connection in the EM model?
Do you see the vias in the 3D EM preview?

PS: When you create the look-alike symbol, you can specify a size or scaling factor, so that it has a more useful size compared to circuit elements.
Yes this is viaground model. For the map the hole layer, Do you mean map conductor via? If so, I did during momentum setup. If no, could you please explain how to do it as this my first time doing momentum simulation? Thanks
 

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Looks good to me. If you question the DC path connection, I recommend to build a simple testcase and probe that, by using DC analysis or S-parameters at DC.
 

Mabrok

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Looks good to me. If you question the DC path connection, I recommend to build a simple testcase and probe that, by using DC analysis or S-parameters at DC.
The s-parameter analysis result is totally wrong, where, S11 & S22 0 dB? I am worry that is my DC grounding is wrong. Also I can not see the holes in 3D preview. thank you. 3D front preview design.pngMomentum co-simulation response.png
 

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I meant a testcase for a DC path.

But looking at your model now, I see ports only at the input and output. Where are all the ports at the circuit components? Did you follow the documented co-simulation workflow?
 

Mabrok

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I meant a testcase for a DC path.

But looking at your model now, I see ports only at the input and output. Where are all the ports at the circuit components? Did you follow the documented co-simulation workflow?
Those ports already deleted in momentum setup ports. If i didn't delete, then will get message stating that calibration cannot be done for ports which are placed inside
the structure One more thing for confirmation, vias in ADS layout window should be set as cond layer or via layer?
 
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volker@muehlhaus

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Those ports already deleted in momentum setup ports.
That's your problem, you can't delete those ports. Then the entire simulation can't work, of course, because components are not connected.

If i didn't delete, then will get message stating that calibration cannot be done for ports which are placed inside the structure
That message is information only, if you forgot to switch calibration off. Calibration is optional, not a must.

One more thing for confirmation, vias in ADS layout window should be set as cond layer or via layer?
The via element in layout has multiple layers, for via ring and the thru hole. The thru hole will create the 3D connection to the ground below.
Cond1Layer= cond
HoleLayer = hole
Cond2Layer= cond2 (doesn't matter, not used here because we use an infinite ground in Momentum)
 
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Mabrok

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That's your problem, you can't delete those ports. Then the entire simulation can't work, of course, because components are not connected.



That message is information only, if you forgot to switch calibration off. Calibration is optional, not a must.



The via element in layout has multiple layers, for via ring and the thru hole. The thru hole will create the 3D connection to the ground below.
Cond1Layer= cond
HoleLayer = hole
Cond2Layer= cond2 (doesn't matter, not used here because we use an infinite ground in Momentum)
So vias in this case should be set as this, via ring as cond, and thru hole as hole, right?
 

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So vias in this case should be set as this, via ring as cond, and thru hole as hole, right?
Yes, correct. This matches the mapping of layer "hole" that you showed above in your Momentum stackup.
If you look at the 3D EM preview, which you can rotate, you will see the vias. If you don't see them, something is wrong.

But make sure you also add in all the ports for the discretes. Port type = "Direct" is what you need, it uses no port calibration.
 
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Mabrok

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Yes, correct. This matches the mapping of layer "hole" that you showed above in your Momentum stackup.
If you look at the 3D EM preview, which you can rotate, you will see the vias. If you don't see them, something is wrong.

But make sure you also add in all the ports for the discretes. Port type = "Direct" is what you need, it uses no port calibration.
What do you mean by port type = "Direct", In ADS Layout port type setup, there is 3 options only : Input, output, Input/output?
As I did all required setup above and still no response S11 0 dB which means something is wrong. Thanks

- - - Updated - - -

What do you mean by port type = "Direct", In ADS Layout port type setup, there is 3 options only : Input, output, Input/output?
As I did all required setup above and still no response S11 0 dB which means something is wrong. Thanks
This is the ports setup in momentum. P1 & P2 for input and output 50 ohm. the rest for components and connection to DC source. Ports setup in momentum.png
 

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What do you mean by port type = "Direct", In ADS Layout port type setup, there is 3 options only : Input, output, Input/output?
I refer to the port calibration setting ("Feed Type"), because that is what your message refers to. In some case, TML isn't possible. ADS will disable it then, and shows the warning. If you don't want the warning, you can disable port calibration yourself, by using "Direct" instead of the default settings (TML).

port_direct.jpg

This is the ports setup in momentum. P1 & P2 for input and output 50 ohm. the rest for components and connection to DC source.
Ok, here we have all the ports. And they don't show up in 3D EM preview?

As I did all required setup above and still no response S11 0 dB which means something is wrong. Thanks
Most likely it's a trivial mistake, but from the information that you give here, it is not possible to find out where the mistake is. I recommend to contact Keysight support and send them your workspace file.
 
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Mabrok

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I refer to the port calibration setting ("Feed Type"), because that is what your message refers to. In some case, TML isn't possible. ADS will disable it then, and shows the warning. If you don't want the warning, you can disable port calibration yourself, by using "Direct" instead of the default settings (TML).

View attachment 156889



Ok, here we have all the ports. And they don't show up in 3D EM preview?



Most likely it's a trivial mistake, but from the information that you give here, it is not possible to find out where the mistake is. I recommend to contact Keysight support and send them your workspace file.
Thanks alot. From where I can access to the port editor shown above.? And is it required to set all ports to direct including P1 & P2 for I/P and O/P or just for components?

- - - Updated - - -

Thanks alot. From where I can access to the port editor shown above.? And is it required to set all ports to direct including P1 & P2 for I/P and O/P or just for components?
And also how about the ground ports (pins placed on the vias), Is it same as others for other components?
you may have a look here for placed pins for via ground, and for component. Is this correct?Untitled11.png
 

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Thanks alot. From where I can access to the port editor shown above.?
What is your ADS version? My screenshot is ADS 2020. In older versions, port calibration is in emSetup > Ports tab as show in your screenshot in #13. In that case, you choose "none" for port calibration, which is the same as "direct" in ASS 2020.

And is it required to set all ports to direct including P1 & P2 for I/P and O/P or just for components?
You're confused now, that is the wrong setting. We don't care about the I/P and O/P settings. It's about port calibration, which is found if different places: older ADS has this in emSetup, new ADS has this is layout . And as I mentioned multiple times, it is only to get rid of the warning that you reported. If you leave port cal to TML, ADS will show a warning and disable port cal automatically.

In short: this will not change S-parameters, just get rid of the warning.

And also how about the ground ports (pins placed on the vias), Is it same as others for other components?
Yes no maybe. As I mentioned a few time above: start from a simple testcase.

I will stop here - you need to get in touch with ADS support. There are too many possible mistakes (from misunderstanding) that we will never catch, even with 20 more pages of discussion here. You need to show your EM cell, setup and schematic to support.
 
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