# s2sdc

Convert 4-port, single-ended S-parameters to 2-port, cross-mode S-parameters (Sdc)

## Syntax

``sdc_params = s2sdc(s_params)``
``sdc_params = s2sdc(s_params,option)``

## Description

example

````sdc_params = s2sdc(s_params)` converts the 2N-port, single-ended S-parameters to N-port, cross-mode S-parameters. ```
````sdc_params = s2sdc(s_params,option)` converts S-parameters based on the optional `option` argument, which indicates the port-ordering convention of the S-parameters.```

## Examples

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Convert network data to cross-mode S-Parameters using the default port ordering.

``` S = sparameters('default.s4p'); s4p = S.Parameters; s_dc = s2sdc(s4p);```

Display the 2-port cross-mode S-Parameters at the first frequency.

` s_dc_new = s_dc(:,:,1)`
```s_dc_new = 2×2 complex 0.0024 - 0.0035i -0.0005 + 0.0019i 0.0007 - 0.0012i 0.0023 - 0.0027i ```

## Input Arguments

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S-parameters, specified as a complex 2N-by-2N-by-M array of complex numbers, where M represents the number of frequency points of 2N-port S-parameters.

Port order, a scalar, specified as `1`, `2`, or `3`. Port order determines how the function orders the ports:

• `1``s2sdc` 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 cross-mode pair 1.

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

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

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

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

• `2``s2sdc` pairs the input and output ports in ascending order. For example, in a single-ended, 8-port network:

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

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

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

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

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

• `3``s2sdc` 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 cross-mode pair 1.

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

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

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

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

## Output Arguments

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N-port cross-mode S-parameters , returned as an N-by-N-by-M array of complex numbers, where M represents the number of frequency points of N-port cross-mode S-parameters (Sdc).

## References

[1] Fan, W., et al. “Mixed-Mode S-Parameter Characterization of Differential Structures.” Proceedings of the 5th Electronics Packaging Technology Conference (EPTC 2003), IEEE, 2003, pp. 533–37. DOI.org (Crossref), doi:10.1109/EPTC.2003.1271579.

## Version History

Introduced in R2006a