Stability factor K of two-port network
[k,b1,b2,delta] = stabilityk(
calculates and returns the stability factor,
k, and the conditions
delta for the
[k,b1,b2,delta] = stabilityk( calculates
and returns the stability factor and stability conditions for the two-port network
represented by the S-parameter object
Examine the stability of network data from a file by first calculating the stability factor.
S = sparameters('passive.s2p'); s_params = S.Parameters; [k,b1,b2,delta] = stabilityk(s_params);
Check stability criteria.
stability_index = (k>1)&(abs(delta)<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.
Necessary and sufficient conditions for stability are
calculates the outputs using the equations
S22 are S-parameters from the input argument
Δ is a vector whose members are the determinants of the M 2-port S-parameter matrices:
The function performs these calculations element-wise for each of the M
S-parameter matrices in
 Gonzalez, Guillermo. Microwave Transistor Amplifiers: Analysis and Design. 2nd ed. Upper Saddle River, N.J: Prentice Hall, 1997.