How to plot propagation constatnt in IE3D or ADS

[si14]

propagation constant plot

Hi all:

I want to calculate the slow-wave factor in a periodic structure. How can I plot the Slow-wave factor for the structure? I think the ratio of (propagation constant of the periodic structure/propagation constant of the reference line) defines the slow wave factor. But how can I plot these propagation constant plots versus frequency in IE3D or ADS?

I am in a hurry and I would be glad if anyone could help me.

Thanks.

 

[jian]

slow wave structure ads

On IE3D, you can solve a short TLN as a 2-port structure. On MGRID->PROCESS->S-PARAMETERS AND LUMPED EQUIAVELNT CIRCUIT. You can select FIND TLN PARAMETERS FROM 2-PORT S-PARAMETERS and GO. On MODUA, you can also find the TLN parameters. You will get tabulated data.

 

[si14]

Thank you very much for your help. I did that. It seems that I don't get proper results. Because IE3D gives me a warning that due to the non-uniform transmission line(which is my slow-wave structure), the results have a low accuracy.

Is it possible to plot the slow-wave factor with the phase of S21. Since the phase(S21) plot can be generated with high accuracy, is it possible to calculate the slow-wave factor from this plot?

phase(S21)=electrical length of the line
AND
phase(S21)=(propagation constant)*(physical length)
==>
propagation constant is obtained.

 

[jian]

The warning is due to the fact IE3D detects the s-parameters do not look exactly like a TLN. You can only pick some good frequency points for it. You are trying to "fit" a TLN model to your non-TLN s-parameters. You can only get some rough results.