Learning Forum

[Preeti]

Hi,

I have designed a planar array using Ansys Electromagnetic Suite 2020 R2, including diodes in the structure. I also have the spice model of the diode used from the manufacturer.

Now, I have first designed my planar array in HFSS without diode, then inserted it into the Ansys Circuit and then connected the spice model of the diode. I got my results using linear frequency sweep.

But, I want to optimize my obtained results now. If I select optimization option in Ansys Circuit, it displays "no local variable". This is because all the design variables are available in HFSS project that has been inserted in the Ansys Circuit System.

Please help.

[tyler.reid]

You can create a dynamic link and create variables in circuit to override the variables in the HFSS solution. I think you precede them with a $ symbol in circuit. Then circuit can use the previously solved solutions (such as a parametric sweep) from HFSS by varying the local circuit variables. For optimization instead of parametric it may be more of a challenge. It's been several versions since I tried this, so they may have improved the linking to force the HFSS to solve any non existing solutions. I think previously it could only use existing solutions. For example if you have a variable patch_width in HFSS you can create a variable called $patch_width in circuit and in the HFSS block inside circuit assign patch_width to $patch_width. Then set $patch_width to be the variable used for optimization in circuit.

[Preeti]

Thank you for your help.

[Praneeth]

You can use project variables to access them across multiple designs in a single AEDT project.
The project variables will have "$" prefix to differentiate them with normal variable which are local variables.
Please go through the HFSS help pdf document to know how to define the project variable.
Are you trying to optimize the HFSS design variable from Circuit?
If so, please be advised to optimize it from HFSS itself rather than Circuit as this change can have impact on the associated fields.
All the very best.

[Preeti]

Dear Sir Thank you for your help.
Yes, I am trying to optimize my HFSS design from Circuit. This is because I am using spice model of diodes along with my HFSS planar array. I need to optimize my results after including these spice models. That is why, I wanted to optimize my HFSS design using Circuit, because I have included these spice models in my design inside Circuit only.
Else, please let me know if there is some other way to include the spice models in the HFSS itself, so that I can optimize my HFSS design there itself, without going to Circuit.
Please help.

[Praneeth]

Yes, you can optimize your spice models in Circuit.
Do you have any variables of spice models defined in HFSS?
Best regards.

[Preeti]

Dear Sir Please note that I do not want to optimize my spice models. I am using the spice models as provided by the manufacturer.
I was trying to say that I wanted to optimize my S-parameters of planar array, which also includes the spice models of diodes. The complete configuration has been implemented in two parts: (a) planar array in HFSS without diodes (lumped port is used in place of diodes); and (b) HFSS design of planar array linked to Circuit and then, spice models of diodes are connected in Circuit. Now, my complete structure is in Circuit, that is why I wanted to optimize the S- parameters of complete geometry (including spice models input) in Circuit.
If there is some other way in HFSS where we can include the spice models of any lumped component (without going to Circuit), please let me know the same.
Otherwise, I will follow your advise and do my optimization in HFSS only (excluding spice models).
Thank you once again for helping me.
Regards

[Praneeth]

You can use cosimulation between HFSS and Circuit to do the required optimization.
Please go through the AIC course - Cosimulation Using Ansys HFSS - ANSYS Innovation Courses on how to do cosimulation using HFSS and Circuit in AEDT.
All the very best.

[Preeti]

Dear Sir Thank you so much for your help.
I will definitely try cosimulation as suggested by you.
Regards