Learning Forum

[psquadrito]

I have a big design imported from Altium into HFSS 3DLayout with several RFIC that i want to simulate. RF and Digital (SPI) nets are included in this design.
I'am interested mainly in the RF side of things so when i cut out of the main design to analyze a specific area the shape of this cut-out is usually driven by the RF nets i want to include in my design. This means that sometimes i can have digital nets floating or partially floating in my subdesign.
I do not want to remove completely the digital part as i would like to evaluate any possible effect on my RF design, and i'm not sure either that terminating this floating/partially floating nets to ground is the right solution.
How do i handle this situation?

[Anchal Singh]

You can set unnecessary parts of your design as 'non-model' so that the solver won't consider them for simulation.
For more information, you can go through the 'Drawing Non-Model Objects' section of the HFSS help document.
Hope this helps.
Regards
Anchal

[psquadrito]

Hi AncSingh. Thank you for the answer. True, you can set non-model object but only in HFSS. To the best of my knowledge there is no such thing in 3DLayout but you can tell the solver to not consider floating objects. However this doesn't address my question entirely since i'm not sure that removing the digital part is the correct approach.
At the end of the day i want to evaluate possible effects of the digital part on my RF design. But sometimes, a cutout of the board can result in floating or semi-floating nets belonging to the digital part. Not sure that leaving them as they are is the right approach either.