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smm2s - Convert mixed-mode 2N-port S-parameters to single-ended 4N-port S-parameters

Syntax

s_params = smm2s(s_dd, s_dc, s_cd, s_cc) s_params = smm2s(s_dd, s_dc, s_cd, s_cc, option)

Description

s_params = smm2s(s_dd, s_dc, s_cd, s_cc) converts mixed-mode, 2N-port S-parameters into single-ended, 4N-port S-parameters, s_params.

s_dd, s_dc, s_cd, and s_cc are complex 2N-by-2N-by-K arrays. s_dd contains differential-mode S-parameters (S_dd), s_dc and s_cd contain cross-mode S-parameters (S_dc and S_cd), and s_cc contain common-mode S-parameters (S_cc).
s_params is a complex 4N-by-4N-by-K array representing K single-ended, 4N-port S-parameters.
K is the number of points in the S-parameter data. Each data point usually corresponds to a different frequency, so K is usually the number of frequency points.

By default, smm2s maps the first half of the mixed-mode ports to the odd-numbered pairs of single-ended ports and maps the second half to the even-numbered pairs.

s_params = smm2s(s_dd, s_dc, s_cd, s_cc, option) converts the S-parameter data using the optional argument option. option indicates the port-numbering convention that the S-parameters use.

option can be:

1 — smm2s maps the first half of the mixed-mode ports to odd-numbered pairs of single-ended ports and maps the second half to even-numbered pairs. For example, in a mixed-mode, 4-port network,
- Port 1 becomes single-ended ports 1 and 3.
- Port 2 becomes single-ended ports 5 and 7.
- Port 3 becomes single-ended ports 2 and 4.
- Port 4 becomes single-ended ports 6 and 8.
The following figure shows this convention.
2 — smm2s maps the first half of the mixed-mode ports to single-ended ports in ascending numerical order, followed by the second half, also in ascending order. For example, in a mixed-mode, 4-port network,
- Port 1 becomes single-ended ports 1 and 2.
- Port 2 becomes single-ended ports 3 and 4.
- Port 3 becomes single-ended ports 5 and 6.
- Port 4 becomes single-ended ports 7 and 8.
The following figure shows this convention.
3 — smm2s maps the first half of the mixed-mode ports to single-ended ports in ascending numerical order. The function maps the second half to pairs of ports in descending order. For example, in a mixed-mode, 4-port network,
- Port 1 becomes single-ended ports 1 and 2.
- Port 2 becomes single-ended ports 3 and 4.
- Port 3 becomes single-ended ports 8 and 7.
- Port 4 becomes single-ended ports 6 and 5.
The following figure shows this convention.

The default value of option is 1.

If you want to reorder the ports in s_params later according to a different port-numbering convention, use the snp2smp function.

Examples

Create sample arrays of 2-port, mixed-mode S-parameters:

 ckt = read(rfckt.passive, 'default.s4p'); 
 s4p = ckt.NetworkData.Data; 
 [sdd, scd, sdc, scc] = s2smm(s4p);

Convert them back to 4-port, single-ended S-parameters:

  s4p_converted_back = smm2s(sdd, scd, sdc, scc);

References

Granberg, T., Handbook of Digital Techniques for High-Speed Design.Upper Saddle River, NJ: Prentice Hall, 2004.

smm2s - Convert mixed-mode 2N-port S-parameters to single-ended 4N-port S-parameters

Syntax

Description

Examples

References

See Also

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