EM simulation of Lange Coupler
I am simulating a Lange Coupler at 6GHz. Which software should I use? ADS, HFSS or Sonnet?
Would ADS FEM and HFSS be okay since they use the same method to solve? How about Sonnet? What method does Sonnet use?
Thanks!
ADS Momentum and Sonnet use the same technique : Method of Moment, so they are convenient for Planar Structures.
HFSS is used for especially 3D structures but it's also convenient even-tough its utilisation is a bit difficult.
You mention ADS FEM, the finite element solver. If your coupler has a planar bridge (no bond wire), I would not use ADS FEM or HFSS for this. They are general 3D solvers and can be used, but require a skilled user to get good results for planar simulation.
ADS Momentum or Sonnet are more optimized for this planar simulation task, including port calibration features, and can provide better (more accurate) results in the hands of non-EM-experts. But if you need to model the bond wire bridge and don't want to staircase-approximate that with Sonnet/Momentum, then of course you can use FEM method.
I do have a bond wire bridge connections in the lange coupler. I tried ADS Momentum and FEM, the results look very similar. But result from Sonnet is very different, which is giving me a hard time because I don't know which one to trust. Theoretically, ADS Momentum and Sonnet should provide similar result right?
I am using bond wire connections in the Lange coupler. I tried ADS Momentum and FEM, results look similar. I never use HFSS and is a bit hesitating if I should try it out.
Yes, I have used both extensively and they agree well when using reasonable mesh density. The one difference (but shouldn't matter here) is how Sonnet handles the side wall capacitance of thick conductors.
There might be some mistake in your Sonnet model -- have you asked Sonnet support to check that?
Another possible error source is the ADS substrate definition, which is shared by Momentum and ADS. Is this different from Sonnet stackup?
My own EM substrate editor m/matl can read and visualize both ADS and Sonnet stackups, but only supports older Sonnet file format.
http://muehlhaus.com/products/material-file-utility