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abcd2s

Convert ABCD-parameters to S-parameters

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Syntax

s_params = abcd2s(abcd_params,z0)

Description

s_params = abcd2s(abcd_params,z0) converts the ABCD-parameters abcd_params into the scattering parameters s_params. z0 is the reference impedance; its default is 50 ohms.

s_params is a complex 2N-by-2N-by-M array, where M representing number of frequency points of a 2N-port S-parameters.

For more information see, RF Network Parameter Objects.

example

Examples

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Open Live Script

Define a matrix of ABCD-parameters.

A =      0.999884396265344 +  0.000129274757618717i;
B =      0.314079483671772 +      2.51935878310427i;
C = -6.56176712108866e-007 + 6.67455405306704e-006i;
D =      0.999806365547959 +  0.000247230611054075i;
abcd_params = [A,B; C,D]
abcd_params = 2×2 complex

   0.9999 + 0.0001i   0.3141 + 2.5194i
  -0.0000 + 0.0000i   0.9998 + 0.0002i

Convert these ABCD parameters to S-parameters.

s_params = abcd2s(abcd_params)
s_params = 2×2 complex

   0.0038 + 0.0248i   0.9961 - 0.0250i
   0.9964 - 0.0254i   0.0037 + 0.0249i

Input Arguments

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The abcd_params input is a complex 2N-by-2N-by-M array, where M representing number of frequency points of a 2N-port ABCD-parameters.

The function assumes that the ABCD-parameter matrices have distinct A, B, C, and D submatrices:

[[A][B][C][D]]

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

References

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

Version History

Introduced before R2006a

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See Also

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