# skrf.calibration.calibration.NISTMultilineTRL¶

class skrf.calibration.calibration.NISTMultilineTRL(measured, Grefls, l, er_est=1, refl_offset=None, ref_plane=0, gamma_root_choice='estimate', k_method='multical', c0=None, z0_ref=50, z0_line=None, *args, **kwargs)[source]

NIST Multiline TRL calibration.

Multiline TRL can use multiple lines to extend bandwidth and accuracy of the calibration. Different line measurements are combined in a way that minimizes the error in calibration.

At every frequency point there should be at least one line pair that has phase difference that is not 0 degrees or a multiple of 180 degrees otherwise calibration equations are singular and accuracy is very poor.

By default the reference impedance of the calibration is the characteristic impedance of the transmission lines. If the characteristic impedance is known reference impedance can be renormalized by giving z0_ref and z0_line. Alternatively if capacitance/length of the transmission line is given with c0 argument, characteristic impedance can be solved assuming that conductance/length is zero.

Algorithm is the one published in [0], but implementation is based on [1].

References

 [0] DeGroot, J. A. Jargon and R. B. Marks, “Multiline TRL revealed,” 60th ARFTG Conference Digest, Fall 2002., Washington, DC, USA, 2002, pp. 131-155.
 [1] Yau “On the metrology of nanoscale Silicon transistors above 100 GHz” Ph.D. dissertation, Dept. Elec. Eng. and Comp. Eng., University of Toronto, Toronto, Canada, 2011.

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 Returns 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 er_eff Effective permittivity of the solved line. error_ntwk The calculated error Network or Network[s] family frequency Frequency object of the calibration. gamma Propagation constant of the solved line. measured_unisolated measured_unterminated normalized_directivity the directivity normalized to the reflection tracking nstandards number of ideal/measurement pairs in calibration nstd Normalized standard deviation of the calibration error. output_from_run Returns 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 total_error Estimate of total error for overdetermined calibration with multiple connections of each standard. unbiased_error Estimate of unbiased error for overdetermined calibration with multiple connections of each standard verify_12term verify_12term_ntwk z0 Solved characteristic impedance of the transmission lines.

Methods

 __init__ NISTMultilineTRL initializer apply_cal Apply correction to a Network apply_cal_to_all_in_dir apply_cal_to_list Apply correction to list of dict of Networks. embed from_coefs Creates a calibration from its error coefficients from_coefs_ntwks Creates a calibration from its error coefficients load_calibration_archive plot_caled_ntwks Plots corrected calibration standards plot_errors Plots 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 Runs the calibration algorithm. save_calibration save calibration as an archive containing the standards, parameters and calibration results terminate Terminate a network with switch terms unterminate Unterminates switch terms from a raw measurement. update_coefs update currect dict of error coefficients write Write the Calibration to disk using write().