Like fine-tuning a race car: the role of calibration and maintenance in optimising VNA performance

June 16, 2014 //By Adam Purkiss, Anritsu (UK)
The modern Vector Network Analyser (VNA) is an extraordinary feat of engineering, enabling the precise measurement and analysis of signals across a broad frequency spectrum, in some cases up to 110 GHz.

VNAs are therefore capable of supporting engineers in the analysis and characterisation of extremely sophisticated and high-performance devices with impressive accuracy and resolution (see Figure 1).

Engineering units which have invested in a VNA will naturally want their advanced instrument to be working at peak performance whenever needed. Perhaps surprisingly, the measures necessary to ensure that the VNA operates reliably and produces accurate results are relatively simple to implement, and cost little (in comparison to the purchase price of the instrument).

And as device operating speeds have grown ever faster, the impact of even minute non-linearities or distortions on the accuracy of a VNA's measurements has grown. So calibration and connection practices which might in years gone by have been acceptable now risk invalidating the results produced by an expensively acquired VNA.

This article shows how following best practice in calibration and maintenance – a course that calls for time and care more than money – can produce a huge reward in improved reliability and accuracy of device measurements.

Figure 1: basic architecture of a VNA.

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