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s2smm - Convert single-ended 4N-port S-parameters to mixed-mode 2N-port S-parameters

Syntax

[s_cc, s_cd, s_dc, s_dd] = s2smm(s_params) [s_cc, s_cd, s_dc, s_dd] = s2smm(s_params, option)

Description

[s_cc, s_cd, s_dc, s_dd] = s2smm(s_params) converts single-ended, 4N-port S-parameters, s_params, into mixed-mode, 2N-port S-parameters.

s_params is a complex 4N-by-4N-by-K array representing K single-ended, 4N-port S-parameters.
s_cc, s_cd, s_dc, and s_dd are complex 2N-by-2N-by-K arrays. s_cc contains common-mode S-parameters (S_cc), s_cd and s_dc contain cross-mode S-parameters (S_cd and S_dc), and s_dd contains differential-mode S-parameters (S_dd).
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.

s2smm forms the mixed-mode ports by grouping the single-ended ports in pairs by port number. By default, the function groups odd-numbered ports first, followed by even-numbered ports.

[s_cc, s_cd, s_dc, s_dd] = s2smm(s_params, option) converts the S-parameter data using the optional option argument. option indicates the port-numbering convention that the S-parameters use.

option can be:

1 — s2smm pairs the odd-numbered ports together first, followed by the even-numbered ports. For example, in a single-ended, 8-port network,
- Ports 1 and 3 become mixed-mode port 1.
- Ports 5 and 7 become mixed-mode port 2.
- Ports 2 and 4 become mixed-mode port 3.
- Ports 6 and 8 become mixed-mode port 4.
The following figure shows this convention.
2 — s2smm pairs the input and output ports in ascending order. For example, in a single-ended, 8-port network,
- Ports 1 and 2 become mixed-mode port 1.
- Ports 3 and 4 become mixed-mode port 2.
- Ports 5 and 6 become mixed-mode port 3.
- Ports 7 and 8 become mixed-mode port 4.
The following figure shows this convention.
3 — s2smm pairs the input ports in ascending order and the output ports in descending order. For example, in a single-ended, 8-port network,
- Ports 1 and 2 become mixed-mode port 1.
- Ports 3 and 4 become mixed-mode port 2.
- Ports 8 and 7 become mixed-mode port 3.
- Ports 6 and 5 become mixed-mode port 4.
The following figure shows this convention.

The default value of option is 1.

If you want s2smm to use a different port-numbering convention, reorder the ports first using the snp2smp function.

Examples

Convert 4-port S-parameters s4p to 2-port mixed-mode S-parameters with the default port-numbering convention:

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

References

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

s2smm - Convert single-ended 4N-port S-parameters to mixed-mode 2N-port S-parameters

Syntax

Description

Examples

References

See Also

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