Documentation

This is machine translation

Translated by Microsoft
Mouseover text to see original. Click the button below to return to the English verison of the page.

Note: This page has been translated by MathWorks. Please click here
To view all translated materals including this page, select Japan from the country navigator on the bottom of this page.

stabilityk

Stability factor K of 2-port network

Syntax

[k,b1,b2,delta] = stabilityk(s_params)
[k,b1,b2,delta] = stabilityk(hs)

Description

[k,b1,b2,delta] = stabilityk(s_params) calculates and returns the stability factor, k, and the conditions b1, b2, and delta for the 2-port network. The input s_params is a complex 2-by-2-by-M array, representing M 2-port S-parameters.

[k,b1,b2,delta] = stabilityk(hs) calculates and returns the stability factor and stability conditions for the 2-port network represented by the S-parameter object hs.

Examples

collapse all

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

ckt = read(rfckt.passive,'passive.s2p');
s_params = ckt.NetworkData.Data;
freq = ckt.NetworkData.Freq;
[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_unstable = freq(~stability_index)
freq_unstable =

  0x1 empty double column vector

Algorithms

Necessary and sufficient conditions for stability are k>1 and abs(delta)<1. stabilityk calculates the outputs using the equations

K=1|S11|2|S22|2+|Δ|22|S12S21|B1=1+|S11|2|S22|2|Δ|2B2=1|S11|2+|S22|2|Δ|2

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

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

References

Gonzalez, Guillermo, Microwave Transistor Amplifiers: Analysis and Design, 2nd edition. Prentice-Hall, 1997, pp. 217–228.

Introduced before R2006a

Was this topic helpful?