S2P File Format

The PEMG software does not use the S2P data. The PD1000A Control Software converts the S2PDIF information into MDM format.

S-parameter characterization data from the ENA is saved in a S2P format. This format is also known as the Touchstone format, as specified by the IBIS Open Forum. This S2P format is also used by CAE programs such as Keysight's Microwave Design System (MDS) and Advanced Design System (ADS). Both Touchstone 1.0 and Touchstone 2.0 files contain S-parameters that describe frequency-dependent linear networks. S2PDIF format is the same but saves additional information.

SnP files contain header information, stimulus data, a response data pair for EACH S-parameter measurement. Specifically, the PD1000A Control Software saves the S-parameter data as S2P files. The difference between S1P, S2P, and so forth, is the number for S-parameters that are saved.

File Type # of Ports # of S-parameters saved
*.s1p 1 1 S-parameter
*.s2p 2 4 S-parameters
*.s3p 3 9 S-parameters
*.s4p 4 16 S-parameters
*.sNp N N2 parameters

The following is a sample of Header information:

! is a commented line.
!Keysight,E8362B,US42340026,Q.03.54
!Keysight E8362B: Q.03.54
!Date: Friday, April 25, 2003 13:46:41
!Correction: S11(Full 2 Port SOLT,1,2) S21(Full 2 Port SOLT,1,2) S12(Full 2 Port SOLT,1,2) S22(Full 2 Port SOLT,1,2)
!S2P File: Measurements:S11,S21,S12,S22:
# Hz S RI R 50

Each record is a data point. There can be up to 16,000 data points (records) in each file.

*.s1p Files

Each record contains 1 stimulus value and 1 S-parameter (total of 3 values).

Stim Real (Sxx) Imag(Sxx)

*.s2p Files

Each record contains 1 stimulus value and 4 S-parameters (total of 9 values)

Stim Real (S11) Imag(S11) Real(S21) Imag(S21) Real(S12) Imag(S12) Real(S22) Imag(S22)

*.s3p Files

Each record contains 1 stimulus value and 9 S-parameters (total of 19 values)

Stim Real (S11) Imag(S11) Real(S12) Imag(S12) Real(S13) Imag(S13)

Real (S21) Imag(S21) Real(S22) Imag(S22) Real(S23) Imag(S23)

Real (S31) Imag(S31) Real(S32) Imag(S32) Real(S33) Imag(S33)

*.s4p Files

Each record contains 1 stimulus value and 16 S-parameters (total of 33 values)

Stim Real (S11) Imag(S11) Real(S12) Imag(S12) Real(S13) Imag(S13) Real(S14) Imag(S14)

Real (S21) Imag(S21) Real(S22) Imag(S22) Real(S23) Imag(S23) Real(S24) Imag(S24)

Real (S31) Imag(S31) Real(S32) Imag(S32) Real(S33) Imag(S33) Real(S34) Imag(S34)

Real (S41) Imag(S41) Real(S42) Imag(S42) Real(S43) Imag(S43) Real(S44) Imag(S44)

This pattern continues for N ports involved in the measurement.

Example

Although the following example shows Real / Imaginary pairs, the format could also be LogMag / Phase or LinMag / Phase

As indicated in the table above, S2P files are for 2-port, four S-parameter measurements (S11, S12, S21, S22). Each record contains one stimulus and four S-parameter pairs (a total of nine values):

Stim, Real (S11), Imag(S11), Real (S21), Imag(S21),Real (S12), Imag(S12),Real (S22), Imag(S22)

Example:

 

The PD1000A control software converts the S2P data to MDM format.