skrf.qfactor.Qfactor.fitted_s

Qfactor.fitted_s(opt_res=None, f=None)[source]

S-parameter response of an equivalent circuit model resonator.

The approximate solution and estimated is obtained from [MAT58]:

\[S = m_1 + j m_2 + \frac{m_3 + j m_4}{1 + j Q_L t}\]

where the m coefficients come from the fitted solution and

\[t = \frac{f}{f_L} - \frac{f_L}{f} \approx 2 \frac{f − f_L}{f_L}\]

Parameters:

opt_res (None or OptimizedResult. Default is None.) – Solution produced by the fit() method. If None, uses the solution previously calculated, if performed.
f (None or np.ndarray. Default is None.) – frequency array [Hz]. If None, use the self frequencies.

Returns:

s – S-parameter response.

Return type:

np.ndarray

References

[MAT58]

“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/, section 2.2, eqn. (21).