Pro Tier Module

RF Cal Lab - VNA Error Correction + Uncertainty

Exact 1-port VNA error correction and a GUM uncertainty budget, computed in your browser.

This tool runs inside GDBS Pro. What it computes and the authorities it applies are below.

The problem

Accredited RF and microwave calibration labs need OSL error correction and a defensible measurement-uncertainty budget that an assessor can reproduce, yet much of that math lives in spreadsheets or instrument firmware no one can audit line by line.

The local-first solution

This plugin computes the textbook 1-port 3-term error correction as an exact complex solve and builds a GUM expanded-uncertainty budget entirely in the browser, with every term traceable to a published reference and no measurement data sent to any cloud.

What it does

Exact 1-port (OSL/SOL) error correction via a 3-term Moebius (directivity, source match, reflection tracking) solve

De-embeds the DUT raw measurement to corrected reflection: |Gamma|, phase, return loss, and VSWR

GUM (JCGM 100) expanded-uncertainty budget combining residual directivity, source match, tracking, noise, connector repeatability, and drift

Mismatch uncertainty limits for a through/power measurement against a source of known match

Published cal-kit library (e.g. Keysight 85033E 3.5 mm) plus custom offset delay/loss and C0-C3 / L0-L3 standard coefficients

Numerical trust verdict from the residual of re-applying the solved error terms to the three standards

Honest scope

The solve and the GUM budget are computed exactly in-browser, and the trust verdict reports only the numerical fidelity of the OSL solve, not a physics validation against an external reference. This is a QA and documentation companion to a calibrated VNA and traceable standards, not a replacement; with the ideal-standards model results are exact only to the extent the kit is ideal, and a mismatched-offset model remains a future increment.

Authorities cited

Rytting, D. K. Network Analyzer Error Models and Calibration Methods. Keysight (Agilent/HP) technical paper. The 1-port 3-term (directivity, source match, reflection tracking) error model and OSL correction.
Keysight Technologies. Specifying Calibration Standards and Kits for Keysight Vector Network Analyzers. App Note 5989-4840EN. Cal-kit standard definitions (offset delay, C0-C3 fringing capacitance, L0-L3 inductance).
JCGM 100:2008 (GUM). Evaluation of measurement data - Guide to the expression of uncertainty in measurement. Combined standard uncertainty by RSS; expanded uncertainty U = k*uc.
ISO/IEC 17025:2017. General requirements for the competence of testing and calibration laboratories. Measurement uncertainty must be evaluated and reported.
Harris, I. A. & Warner, F. L. (1981). Re-examination of mismatch uncertainty when measuring microwave power and attenuation. IEE Proc. H 128(1), 35-41. Mismatch limits +/- 20 log10(1 +/- |Gs||Gl|).
Keysight Technologies. 85033E 3.5 mm Calibration Kit User and Service Guide (doc 9018-01293). Standard definitions for the DC-9 GHz 3.5 mm SOLT kit.
scikit-rf project. SOLT Calibration Standards Creation - tabulated 85033E definitions (open C0-C3, short L0-L3, offset delay/loss), sourced from the Keysight kit definition. https://scikit-rf.readthedocs.io

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Background reading: RF and electrical engineering

Run a cal in your browser

Correct a measurement and generate the uncertainty budget client-side, then route the result into a Sandbox workspace, a Worklog case, or a Gate client portal. Nothing is uploaded to anyone's cloud.

Try it live inside GDBS See Pro pricing

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