skrf.qfactor.Qfactor.fit

Qfactor.fit(method='NLQFIT6', loop_plan='fwfwc')[source]

Fit Q-factor from S-parameter data.

Fitting overwrites the parameters Q_L and f_L.

Parameters:

  • method (str, optional) –

    Fitting method : ‘NLQFIT6’ (default), ‘NLQFIT7’, ‘NLQFIT8’:

    • ’NLQFIT6’: Least Square Minimum of Eq.21 [MAT58] with 6 coeffcients.

    • ’NLQFIT7’: Least Square Minimum of Eq.26 [MAT58] with 7 coeffcients, including one that characterize the trans. line length.

    • ’NLQFIT8’: Least Square Minimum of Eq.43 [MAT58] with 8 coeffcients, A model for frequency-dependent leakage.

  • loop_plan (str, optional) –

    Defines order of steps used by the fitting process. The convergence algorithm uses a number of steps set by loop_plan, a string of characters as follows:

    • ’f’: fit once without testing for convergence

    • ’c’: repeated fit, iterating until convergence is obtained

    • ’w’: re-calculate weighting factors on basis of previous fit

    • Initially the weighting factors are all unity.

    • The first character in loop_plan must not be ‘w’.

    e.g.: ‘fwfwc’ (default).

Returns:

result

Return type:

OptimizedResult

References

[MAT58] (1,2,3)

“Q-factor Measurement by using a Vector Network Analyser”, A. P. Gregory, National Physical Laboratory Report MAT 58 (2021) https://eprintspublications.npl.co.uk/9304/