Total Differential Errors in Two-Port Network Analyser Measurements

TL;DR

This paper introduces a method to estimate and visualize uncertainties in two-port VNA measurements using total differential errors and differential error regions, demonstrated on a simple T-network.

Contribution

It presents a novel approach employing total differential errors and DERs to quantify measurement uncertainties in two-port VNA data.

Findings

DERs effectively represent complex differential errors.

Method validated on a T-network with extended transmission lines.

Provides more accurate uncertainty estimation in VNA measurements.

Abstract

Since S-parameter measurements without uncertainty cannot claim any credibility, the uncertainties in full two-port Vector Network Analyser (VNA) measurements were estimated using total complex differentials (Total Differential Errors). To express precisely a comparison relation between complex differential errors, their differential error regions (DERs) were used. To demonstrate the method in the most accurate case of a direct zero-length thru, practical results are presented for commonly used Z-parameters of a simple, two-port, DC resistive T-network, which was built and tested against frequency with a VNA measurement system extended by two lengthy transmission lines.