DesignCon 2022 Schedule Builder

Vector Network Analyzers (VNA) have been around for decades. The instrument quickly evolved into a very useful tool for the RF and microwave engineers, but to exploit the full benefits of the instrument, calibrations are required. The practicing engineer doing VNA measurements dont necessarily need to know the inner workings of the calibration process as long as the proper calibration technique is selected for the given measurement task and the pre-defined calibration steps are thoroughly followed. Yet, there are a lot of potential misconceptions and misunderstandings about the VNA calibration and what to expect from it, which often could lead to wrong interpretation of the results. Out of the many possible calibration techniques, this paper focuses only on two widely used calibration options, which are commonly called SOLT (SHORT-OPEN-LOAD-THRU) and SOLR (SHORT-OPEN-LOAD-REFLECT, also called Unknown THRU) calibrations. The paper focuses on one- and two-port VNA calibrations with mechanical standards. This paper is intended to help practicing VNA users with tidbits and with measured and simulated S-parameter data illustrating correct and incorrect expectations and procedures.

Takeaway

To make sure that there was no operator error or defective interconnect in the calibration, VNA users need a basic understanding of the calibration process and calibration standards. This paper gives practical guidance for users to avoid common mistakes.