s2smm

Convert single-ended S-parameters to mixed-mode S-parameters

Syntax

[s_dd,s_dc,s_cd,s_cc] = s2smm(s_params_even)
s_mm = s2smm(s_params_odd,option)

Description

[s_dd,s_dc,s_cd,s_cc] = s2smm(s_params_even) converts the 2N-port, single-ended S-parameters s_params_even into N-port, mixed-mode S-parameters. s2smm forms the mixed-mode ports by grouping the single-ended ports in pairs by port number (index), grouping odd-numbered ports first, followed by even-numbered ports.

s_mm = s2smm(s_params_odd,option) converts the S-parameter data according the port-numbering convention specified by option. You can also reorder the ports in s_params using the snp2smp function.

Input Arguments

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s_params_even — S-parametersarray

S-parameters, specified as a complex 2N-by-2N-by-K array, representing K single-ended, 2N-port S-parameters. These parameters describe a device with an even number of ports.

option — Port order1 (default) | 2 | 3

Port order, specified as 1, 2, 3, determines how the function orders the ports:

  • 1s2smm 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 pair 1.

    • Ports 5 and 7 become mixed-mode pair 2.

    • Ports 2 and 4 become mixed-mode pair 3.

    • Ports 6 and 8 become mixed-mode pair 4.

    The following figure illustrates this convention for an 8-port device.

  • 2s2smm 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 pair 1.

    • Ports 3 and 4 become mixed-mode pair 2.

    • Ports 5 and 6 become mixed-mode pair 3.

    • Ports 7 and 8 become mixed-mode pair 4.

    The following figure illustrates this convention for an 8-port device.

  • 3s2smm 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 pair 1.

    • Ports 3 and 4 become mixed-mode pair 2.

    • Ports 8 and 7 become mixed-mode pair 3.

    • Ports 6 and 5 become mixed-mode pair 4.

    The following figure illustrates this convention for an 8-port device.

s_params_odd — S-parametersarray

s_params_odd is a complex (2N + 1)-by-(2N + 1)-by-K array representing K single-ended, 2N-port S-parameters. These parameters describe a device with an odd number of ports.

The port-ordering argument option is not available for (2N + 1)-by-(2N + 1)-by-K input arrays. In this case, the ports are always paired in ascending order, and the last port remains single-ended. For example, in a 7-port network:

  • Ports 1 and 2 become mixed-mode pair 1.

  • Ports 3 and 4 become mixed-mode pair 2.

  • Ports 5 and 6 become mixed-mode pair 3.

  • Ports 7 remains single ended.

The following figure illustrates this convention for a 7-port device.

Output Arguments

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s_dd — S-parametersarray

S-parameters, returned as complex N-by-N-by-K array, containing K matrices of differential-mode, 2N-port S-parameters (Sdd).

s_dc — S-parametersarray

S-parameters, returned as a complex N-by-N-by-K array, containing K matrices of cross-mode, N-port S-parameters (Sdc).

s_cd — S-parametersarray

S-parameters, returned as a complex N-by-N-by-K array containing K matrices of cross-mode, N-port S-parameters (Scd).

s_cc — S-parametersarray

S-parameters, returned as a complex N-by-N-by-K array containing K matrices of common-mode, N-port S-parameters (Scc).

s_mm — S-parametersarray

Sparameters, returned as a complex (2N + 1)-by-(2N + 1)-by-K array containing K matrices of mixed-mode S-parameters. The parameters are organized in the matrix as follows:

[Sdd,11Sdd,1NSdc,11Sdc,1NSds,1Sdd,N1Sdd,NNSdc,N1Sdc,NNSds,NScd,11Scd,1NScc,11Scc,1NScs,1Scd,N1Scd,NNScc,N1Scc,NNScs,NSsd,1Ssd,NSsc,1Ssc,NSss]

Examples

Convert 4-port S-parameters to 2-port, mixed-mode S-parameters:

 ckt = read(rfckt.passive,'default.s4p'); 
 s4p = ckt.NetworkData.Data; 
 [s_dd,s_dc,s_cd,s_cc] = s2smm(s4p); 

References

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

See Also

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