# s2abcd

Convert S-parameters to ABCD-parameters

## Syntax

``abcd_params = s2abcd(s_params,z0)``

## Description

example

````abcd_params = s2abcd(s_params,z0)`converts the scattering parameters to the ABCD-parameters. ```

## Examples

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Define a matrix of S-parameters.

```s_11 = 0.61*exp(j*165/180*pi); s_21 = 3.72*exp(j*59/180*pi); s_12 = 0.05*exp(j*42/180*pi); s_22 = 0.45*exp(j*(-48/180)*pi); s_params = [s_11 s_12; s_21 s_22]; z0 = 50;```

Convert S-parameters to ABCD-parameters.

`abcd_params = s2abcd(s_params,z0)`
```abcd_params = 2×2 complex 0.0633 + 0.0069i 1.4958 - 3.9839i 0.0022 - 0.0024i 0.0732 - 0.2664i ```

## Input Arguments

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

Reference impedance in ohms, specified as one of the following:

• Positive real scalar when you want to specify the same the reference impedance for all ports in the network.

• Positive real vector of length N when you want to specify a different reference impedance for each port in the N-port network. (since R2023a)

• Positive real vector of length K when you want to specify a different reference impedance for each in the K frequencies in the data. (since R2023a)

If the reference impedance is a vector and the number of ports N equals the number of data frequencies K, N == K, then the `sparameters` object will assign each element of the vector to each port of the network. To specify reference impedances for each frequency in this case, specify `Z0` as a 3-D vector of length 1-by-1-by-K .

## Output Arguments

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2N-port ABCD parameters, returned as a complex 2N-by-2N-by-M array, where M represents the number of frequency points of 2N-port ABCD-parameters. The output ABCD-parameters matrices have distinct A, B, C, and D submatrices:

`$\left[\begin{array}{cc}\left[A\right]& \left[B\right]\\ \left[C\right]& \left[D\right]\end{array}\right]$`

## References

[1] Pozar, David M. Microwave Engineering. 3rd ed, J. Wiley, 2005.

## Version History

Introduced before R2006a

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