Stability factor μ of two-port network
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
s_params— Two-port S-parameters
Two-port S-parameters, specified as a complex 2-by-2-by-M array. M is the number of two-port S-parameters.
hs— Two-port network
Two-port network, specified as an S-parameter object.
mu— Minimum distance between center of unit Smith chart and unstable region in load plane
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.
muprime— Minimum distance between center of unit Smith chart and unstable region in source plane
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.
stabilitymu calculates the stability factors using the equations
S22 are S-parameters, from the input
Δ is a vector whose members are the determinants of the M 2-port S-parameter matrices:
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
 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.