HFFS and Impedance Measurement

I've been trying to measure the impadance in a CPW line using HFSS. Inout impadance is quite accurate but output impdance deppends on line length!!! I think this is not true.

I've been desing the waveports (in & out) using HFSS specifications and the impdance measurement i'm using is the Zo parameter at Matrix Data

Any idea???
THanks a lot!

Try to use Zpv for CPW structure. Increase the accuracy of the port to e.g. 0.1%.
The rule of thumb in defining the waveport size is quite flexible. Try to see to field magnitude at the port after simulation. If the difference between the highest and the lowest value is large (e.g. 1e3), you may reduce the port size to get more accurate result.

wlcsp

Thanks a lot! I will try it and tell if it worked