skrf.calibration.calibration.LRRM

class skrf.calibration.calibration.LRRM(measured, ideals, switch_terms=None, isolation=None, z0=50, match_fit='l', *args, **kwargs)[source]

Line-Reflect-Reflect-Match self-calibration.

The required calibration standards are:

  • Line: Fully known.

  • Reflect: Unknown reflect, phase needs to be known within 90 degrees.

  • Reflect: Reflect with known absolute value of the reflection coefficient, phase needs to be known within 90 degrees. Different from the other reflect.

  • Match: Match with known resistance in series with unknown inductance.

Reflects are assumed to be identical on both ports. Note that the first reflect’s magnitude of the reflection coefficient can be unknown, but the second reflect’s magnitude of the reflection coefficient needs to be known. Match needs to be only measured on the first port, the second port of match measurement is not used during the calibration.

If match_fit == ‘lc’ then the second reflect is assumed to be a lossless capacitor. Measurements should then include low frequencies for accurate open capacitance determination.

Implementation is based on papers 1 and 2. ‘lc’ match_fit based on 3.

References

1

Zhao, W.; Liu, S.; Wang, H.; Liu, Y.; Zhang, S.; Cheng, C.; Feng, K.; Ocket, I.; Schreurs, D.; Nauwelaers, B.; Qin, H.; Yang, X. A Unified Approach for Reformulations of LRM/LRMM/LRRM Calibration Algorithms Based on the T-Matrix Representation. Appl. Sci. 2017, 7, 866.

2

F. Purroy and L. Pradell, “New theoretical analysis of the LRRM calibration technique for vector network analyzers,” in IEEE Transactions on Instrumentation and Measurement, vol. 50, no. 5, pp. 1307-1314, Oct. 2001.

3

S. Liu, I. Ocket, A. Lewandowski, D. Schreurs and B. Nauwelaers, “An Improved Line-Reflect-Reflect-Match Calibration With an Enhanced Load Model,” in IEEE Microwave and Wireless Components Letters, vol. 27, no. 1, pp. 97-99, Jan. 2017.

Attributes

T_matrices

Intermediate matrices used for embedding and de-embedding.

biased_error

Estimate of biased error for overdetermined calibration with multiple connections of each standard.

caled_ntwk_sets

Return a NetworkSet for each caled_ntwk, grouped by their names.

caled_ntwks

List of the corrected calibration standards.

coefs

Dictionary or error coefficients in form of numpy arrays.

coefs_12term

Dictionary of error coefficients for 12-term Model.

coefs_12term_ntwks

Dictionary or error coefficients in form of Network objects.

coefs_3term

Dictionary of error coefficients for One-port Error model.

coefs_3term_ntwks

Dictionary of error coefficients in form of Network objects.

coefs_8term

Dictionary of error coefficients for 8-term (Error-box) Model.

coefs_8term_ntwks

Dictionary of error coefficients in form of Network objects.

coefs_ntwks

Dictionary of error coefficients in form of Network objects.

error_ntwk

The calculated error Network or Network[s].

family

frequency

Frequency object of the calibration.

measured_unisolated

measured_unterminated

normalized_directivity

Directivity normalized to the reflection tracking.

nstandards

Number of ideal/measurement pairs in calibration.

output_from_run

Return any output from the run().

residual_ntwk_sets

Returns a NetworkSet for each residual_ntwk, grouped by their names.

residual_ntwks

Dictionary of residual Networks.

solved_c

Solved capacitance of the load.

solved_l

Solved inductance of the load

solved_m

Solved match

solved_r1

Solved reflect1

solved_r2

Solved reflect2

total_error

Estimate of total error for overdetermined calibration with multiple connections of each standard.This is the combined effects of both biased and un-biased errors.

unbiased_error

Estimate of unbiased error for overdetermined calibration with multiple connections of each standard.

verify_12term

verify_12term_ntwk

Methods

__init__

LRRM Initializer.

apply_cal

Apply correction to a Network.

apply_cal_to_all_in_dir

Apply correction to all touchstone files in a given directory.

apply_cal_to_list

Apply correction to list of dict of Networks.

apply_cal_to_network_set

Apply correction to a NetworkSet.

embed

from_coefs

Create a calibration from its error coefficients.

from_coefs_ntwks

Create a calibration from its error coefficients.

plot_caled_ntwks

Plot corrected calibration standards.

plot_errors

Plot biased, unbiased and total error in dB scaled.

plot_residuals

Plot residual networks.

pop

Remove and return tuple of (ideal, measured) at index.

remove_and_cal

Remove a cal standard and correct it, returning correct and ideal.

renormalize

Renormalizes the calibration error boxes to a new reference impedance.

run

Run the calibration algorithm.

terminate

Terminate a network with switch terms.

unterminate

Unterminates switch terms from a raw measurement.

update_coefs

Update current dict of error coefficients.

write

Write the Calibration to disk using write().