Different s2p file sequences

[myem]

When I finished inductance simulation by Ansoft software
and export to s2p file.
Then I view the content of s2p file.
The sequence of S-parameter is S11 S21 S12 S22.

But when I used Agilent ADS simulator ,
the S-parameter is S11 S12 S21 S22.

what would happen if the sequence is not the same ?

THX

 

[mmirmak]

.s2p file format

For truly passive interconnects and devices, you will likely not see too much difference between S12 and S21. However, for automated extraction you should probably correct the Touchstone (R) files to have the same ordering.

The IBIS Open Forum worked with Agilent some time ago to produce a draft specification document for Touchstone(R), as Touchstone(R) is supported by the IBIS Interconnect Modeling (ICM) Specification. You can find the draft specification document below:

**broken link removed**

I hope this helps!

- Michael Mirmak
Intel Corp.
Chair, EIA IBIS Open Forum

 

[fantomf4]

how to open s2p file

When you finished simulation, which format have you choosen for export?

 

[qqyak]

s2p format

please,how to choose the sequence of S11/S21/S12/S22.THANK YOU

 

[mmirmak]

s2p files format

The ordering of S12 and S21 may be dependent on your simulation tool; typically, S11 appears first and S22 appears last.

Please check your tool's documentation and compare it against the draft Touchstone(R) specification mentioned in the link listed in the previous message. In some cases, particularly if your data file was extracted from another format automatically, the file will contain comments which list the order of data listing.

Good luck!

- Michael Mirmak
Intel Corp.
Chair, EIA IBIS Open Forum
http://www.eigroup.org/ibis/
**broken link removed**

 

[itaifrenkel]

s param files viewer .s2p

Hi all,

This is from the draft

Example 4:
!2-port S-parameter file, three frequency points
# GHZ S RI R 50.0
!freq RelS11 ImS11 ReS21 ImS21 ReS12 ImS12 ReS22 ImS22
1.0000 0.3926 -0.1211 -0.0003 -0.0021 -0.0003 -0.0021 0.3926 -0.1211
2.0000 0.3517 -0.3054 -0.0096 -0.0298 -0.0096 -0.0298 0.3517 -0.3054
10.000 0.3419 0.3336 -0.0134 0.0379 -0.0134 0.0379 0.3419 0.3336


Itai

 

[mmirmak]

s2p s11 s12

Itai,

This is indeed the Touchstone(R) order. However, please note that the draft is not an official national or international standard. The draft, and therefore the ordering of the S12 versus S21 columns, is only a recommendation from the original Touchstone(R) authors and may not be followed in precisely the same way by all tool vendors.

Please check the tool vendors' documentation before performing any math operations on the data, for peace of mind.

- Michael Mirmak
Intel Corp.
Chair, EIA IBIS Open Forum

 

[hitmo]

touchstone s2p specification

check the magnitude of s21 and s12 u will know which is wat s21 will be usually a bigger value than s12