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Problem with EM Mesh frequency and Mesh Density

Question asked by jeff0283 on Dec 8, 2015
Latest reply on Feb 13, 2016 by jeff0283
Hi everyone:

This is my circuit :
schematic.png(using CPWG component in TLines-Waveguide)
layout_all.png
layout.png
cosimulation.png

I want to see S11 on the smith chart.
But I don't know exactly how to set the mesh frequency and mesh density at the em setup.
Someone tells me the mesh frequency should be 3 times as much as the operating frequency, and the mesh density can be set to be 20 cells/wavelength.

Here is my em setup:
Mesh setup.png
My operating frequency is at 2.4GHz ,single sweep, so I  set the mesh frequency=2.4*3=7.2 GHz, and the mesh density=20.

But when I change the mesh density to be 40, the result on the smith chart is different from the result of which the mesh frequency is 20.
Here is the result, where the green point is the result of schematic, the red point is the result of cosimulation at mesh frequency=40, and the blue point is the one at mesh frequency =20. 
result.png

I don't know which is the correct result and setting.
Thanks for replying.  

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