The match calculator of the VNA software calculates one or more 'ideal' match circuits to convert a selected point on the Smith chart to the desired impedance, usually 50 Ohm. This results in an 'ideal' match at the selected frequency but this may give a very small bandwidth of the matched network. The circuit will also give non-standard values that must be approximated with E24 or other component series values.
VNA software 1.5.4 and later have an enhanced matching calculator that allows the user to adjust the values of the matching components. This facilitates tuning the components so that the resulting Smith diagram can go slightly 'around' the target impedance instead of going dead center. This can result in a larger bandwidth of the matched network. To assist in the tuning the software also shows the bandwidth of the network, the range with a return loss better than 10dB.
The figure below shows the retuned match circuit with the resulting characteristics.
This software version can be downloaded from our resource page. The user can test these functions with the sample data that is included in the package, without having a VNA connected.