skrf.qfactor.Qfactor

class skrf.qfactor.Qfactor(ntwk, res_type, Q_L0=None, f_L0=None, verbose=False)[source]

Q-factor calculation class.

This class implements methods for determining loaded and unloaded Q-factor from frequency-domain S-parameters, that can be applied to measurements of transmission or reflection.

Parameters:

ntwk (Network object) – A 1-port scikit-rf Network. If your device is a N-port, pass the desired sub-S-parameters to fit the data from, like ntwk.s21.
res_type (str) – Specifies the resonance type: ‘reflection’, ‘transmission’, ‘reflection_method2’ or ‘absorption’: ‘reflection’ is generally suited for undercoupled resonators, while ‘reflection_method2’ is favoured for coupling with large loop.
Q_L0 (float, optional. Default is None.) – Estimated loaded Q-factor, used to improve fitting.
f_L0 (float, optional. Default is None.) – Estimated loaded resonant frequency, used to improve fitting [Hz] If None, automatically search for the min or max, depending on the resonance type defined by res_type.
verbose (bool, optional. Default is False.) – Boolean flag controlling output of information to the console.

Raises:

ValueError – If the passed Network is not 1-port or if the resonance type is unknown.

Notes

Uncalibrated line should be de-embedded (if it has significant length) from the S-parameter data before calling the functions in this module to get best results.

Attributes

`BW`	3-dB Bandwidth.
`BW_scaled`	3-dB Bandwidth scaled to the frequency unit.
`f_L_scaled`	Resonant Frequency in the frequency unit..

Methods

`Q_circle`	Q-circle diameter.
`Q_unloaded`	Unloaded Q-factor Q0.
`__init__`	Q-factor initializer.
`angular_weights`	Diagonal elements W_i of weights matrix.
`fit`	Fit Q-factor from S-parameter data.
`fitted_network`	Fitted Network.
`fitted_s`	S-parameter response of an equivalent circuit model resonator.