Pyaedt Q3D, 2D Extractor : either get modal impedance values or export them

[EEnjk]

I have a Q3D model of a COAX that I am writing my first PyAedt code for.
The code creates the model it simulates. Now I'm trying to extract the data.
The solution is just at one frequency, ie., no sweep.
I am after the Modal Characteristic Impedance. If I pump out a script using the Tools->Record Script to File,
the Iron Python code looks like this.

----------------------------------------------

Script Recorded by Ansys Electronics Desktop Version 2025.1.0

12:59:28 Apr 09, 2025

----------------------------------------------

import ScriptEnv
ScriptEnv.Initialize("Ansoft.ElectronicsDesktop")
oDesktop.RestoreWindow()
oProject = oDesktop.SetActiveProject("coax_circles_manual")
oDesign = oProject.SetActiveDesign("COAX_1")
oDesign.ExportTlineMatrix("D:/Temp/coax_circles_manual_COAX_1.txt", "ModalZ0,Propagation", 500000000, "", "500_MHz:LastAdaptive", "Original", "ohm", "nH", "pF", "mSie", "ns", "Distributed", "1meter", "1ns", "LengthPerTime", "NPPerLength")

                         and the text output looks like this(which is what I am after)

500_MHz:LastAdaptive
C Units: pF, G Units: mSie, R Units: ohm, L Units: nH, Length Units: meter, TimeUnits: ns
Reduce Matrix:Original

Modal Characteristic Impedance (ohm, ohm)
Mode 1
Z0 (57.904,-0.86136)

Propagation
Mode 1
Velocity (meter/ns) 0.20417
Delay (ns/meter) 4.898
Attenuation (Np/meter) 0.2289
Eps_Eff 2.1561
Lamda Eff (meter) 0.40833

I'm trying to do this same thing using Pyaedt and C-Python.
Can someone guide me as to how to grab this data?
I am reaching out because my usage of

data=q.post.get_solution_data() or
or
q.export_results()

are either misdirected or incorrect.

Thx

[gmalinve]

Hi @EEnjk,

Did you try with the export_matrix_data method as suggested in this other discussion: https://github.com/ansys/pyaedt/discussions/6014?

Hope this helps,

Kind regards,

Giulia

[EEnjk]

I tried the following. It exports the CG data, but at 1Hz. This problem is solved with a sweep whose name is:
"10Hz_to_1GHz" Which is odd, because 1Hz is not in the solution range.

Here is the code I tried:
solution_data = q.export_matrix_data("D:\Temp\Matrix_Ansys_CG.csv",problem_type="CG",
setup="1GHz",sweep="10_Hz_to_1GHz")

The sweep is specified above, how do I export data at a specified frequency, such as 1GHz ? or all the sweep data?

Thx

[EEnjk]

ok, I'm a bit slow, I added this to the metho input: freq=1e9 as below

solution_data = q.export_matrix_data("D:\Temp\Matrix_Ansys_CG.csv",problem_type="CG",
setup="1GHz",sweep="10_Hz_to_1GHz",freq=1e9)

and the output csv now indicates a freq of 1e9.

I did this both for the CG and RL outputs. Then I did Z0=sqrt(L/C) after accounting that L is in nH and C in pf.
ie., multiply L by 1e9 and C by 1e12.
The result is off by 1000.

If I go into the created Q3D project and pull up the solutions, the values for L and C(at 1GHz)
are what is in the .csv I just created / exported them to. ie., the csv results match what is in the tool.

But when I go into the Mode data and look at the computed impedance for the mode, that impedance is correct and matches what I expected. The number is the same as computed from the matrix data but greater by a factor of 1000.

ie., the Matrix computed impedance is .049852 ohms, whereas
Modal impedance is 49.852 ohms

ie., the digits are identical, the decimal place is off.

Do you know if this is a bug in the tool?
Did I miss something wrt scaling?

[gmalinve]

Hi @EEnjk,

This is related to AEDT and not to PyAEDT it seems.
Are you in Q2D when trying to export the mode data? if this is the case could you please check the length of your model? It seems that even if you use a distributed model the export accounts for the length.

Giulia

[gmalinve]

Hi @EEnjk,

Let us know if you still need help otherwise I'll proceed by closing this discussion.

Thanks,

Giulia

[EEnjk]

yes I am in Q2D. The impedance calculation question seems to be more suited for an Ansys support case. I will take it up as such.

Here is the code that kicks Q2D into action

project_name = aac.generate_unique_project_name(project_name="coax")
non_graphical = False
q = aac.Q2d(project=project_name,
design="COAX_1",
version="2025.1",
non_graphical=non_graphical,
new_desktop=True
)

stuff in the middle here that actually created the geometries, assigns materials and sets up the soln.

q.analyze()
a = q.post.get_solution_data(expressions="Z0(circle_conductor,circle_conductor)", context="Original")
a.export_data_to_csv("D:\Temp\Z0_Ansys.csv",",")

This all works.
The export line above dumps out the real and imaginary impedance values for all the solved frequencies.

What I am still perplexed about is how to dump the modal data.
in the expressions portion above: expressions="Z0(circle_conductor,circle_conductor)"
is there a syntax for modal data?
I'll keep experimenting on my end.
Thx