We wish to tune a "real" filter using simulated data by loading the simulated S-parameters into a VNA and converting them (S11 & S22) from the frequency to the time domain, allowing us to then follow the procedure outlined in e.g. AN 1287-8.
Is this possible? If so, which VNAs are recommended?
With any of the PNA, PNA-X, or ENA analyzers you can load the simulated data in the analyzer in the form of an S2P (touchstone forma) and if you have the time domain option (option 010) on that box, you can perform a time domain transform on the data loaded from the S2P file. There are other ways to do this, but this is the most straight forward and simple approach.