Main Content

stabilitymu

Stability factor μ of two-port network

Description

example

[mu,muprime] = stabilitymu(s_params) calculates and returns the stability factor, μ, and μ' for the two-port S-parameters

[mu,muprime] = stabilitymu(hs) calculates and returns the stability factor for the two-port network represented by the S-parameter object hs.

Examples

collapse all

Examine the stability factor of network data from a file by calculating the stability factor and conditions.

Calculate the stability factor of network data from a file.

S = sparameters('passive.s2p');
s_params = S.Parameters;
[mu,muprime] = stabilitymu(s_params);

Check stability criteria.

stability_index = (mu>1)|(muprime>1);
is_stable = all(stability_index)
is_stable = logical
   1

List frequencies with unstable S-parameters.

freq = S.Frequencies;
freq_unstable = freq(~stability_index)
freq_unstable =

  0x1 empty double column vector

Input Arguments

collapse all

Two-port S-parameters, specified as a complex 2-by-2-by-M array. M is the number of two-port S-parameters.

Data Types: double

Two-port network, specified as an S-parameter object.

Data Types: function_handle

Output Arguments

collapse all

Minimum distance between the center of the unit Smith chart and the unstable region in the load plane, returned as vector equal to the number of frequency or data points.

Minimum distance between the center of the unit Smith chart and the unstable region in the source plane, returned as a vector equal to the number of frequency or data points.

Algorithms

stabilitymu calculates the stability factors using the equations

μ=1|S11|2|S22S11*Δ|+|S21S12|μ=1|S22|2|S11S22*Δ|+|S21S12|

where:

  • S11, S12, S21, and S22 are S-parameters, from the input argument s_params.

  • Δ is a vector whose members are the determinants of the M 2-port S-parameter matrices:

    Δ=S11S22S12S21

  • S* is the complex conjugate of the corresponding S-parameter.

The function performs these calculations element-wise for each of the M S-parameter matrices in s_params.

References

[1] Edwards, M.L., and J.H. Sinsky. “A New Criterion for Linear 2-Port Stability Using a Single Geometrically Derived Parameter.” IEEE Transactions on Microwave Theory and Techniques 40, no. 12 (December 1992): 2303–11. https://doi.org/10.1109/22.179894.

See Also

Introduced before R2006a