Learning Forum

[Andrew]

Hi 
I have a PCB 6 layer board which i am simulating in Ansys Q3D to extract plane inductance between two different points. Initially i defined two points as mentioned in picture as A to be the source and sink and i got about 25nH inductance i then changed the terminal and excitation to point B and added a smaller piece of sheet as well for one terminal which i unite with main plane. At point B i got like half of inductance as compared to point A. Why is this so? a difference of 1 to 2nH can be expected but this much difference is not logical at all.
Any help regarding this will be appreciated. Can i add sheet in way like i have added and unite it with board plane?
My workflow is like this 
1)I connected different layers together to form a connected conductor.
2)Then i unite the whole assembly
3)Assign excitation(sorce/sink) to the single net
Is there something wrong with workflow?

 

[Mrinmoy Bharadwaj]

Hello Abdul Qadeer Khan,

The tool calculates inductance based on the geometry by generating a mesh and excitation set-up. If you do need to compare that to an analytical derivation, please try that on a simpler geometry to get better understanding and confidence over the tool before trying out on complex gemetries where analytical derivations are either very difficult or not mathematically traceable. I hope this helps. 

[Andrew]

Thanks make sense.