Calculating VNA Measurement Accuracy

By Anritsu Company

Introduction

Vector Network Analyzers (VNA) are your primary resource when analyzing and characterizing systems and components for RF and Microwave measurements. They are regarded as accurate measuring instruments, however, quantifying the accuracy performance of a VNA in a specific application can be challenging. VNA specifications are a starting point; but, they are based upon very specific calibration and measurement conditions, which are not applicable for many applications. The Anritsu Exact Uncertainty program (Model No. 2300-361 and available at www.anritsu.com) is available to help you obtain the uncertainty data that is appropriate for your specific application.

The international standard, ISO/IEC 17025, promulgates the essential requirements for demonstration of the competence of testing and calibration laboratories. It covers testing and calibration performed using standard methods, non-standard methods, and laboratory-developed methods. The ability to express uncertainty of measurement is the key element of assurance of competence. Section 5.4.6 of the standards specifies the requirements of estimation of uncertainty of measurement. "A calibration laboratory, or a testing laboratory performing its own calibrations, shall have and shall apply a procedure to estimate the uncertainty of measurement for all calibrations and types of calibrations."

The Exact Uncertainty program is one method of addressing the estimation requirement.