As with 2-port noise figure, it may be desirable to embed or de-embed networks from the measurement (probes, for example). With multiport DUTs, the networks to be added/subtracted can also be multiport, so some logistical complications arise as with gain. .S2p files are always supported and they are embedded/de-embedded in a simple single-ended sense where one file is associated with each port pair. For an .s4p file, the paths will be treated as single-ended as well, since mode-conversion calculations at this stage are prone to error. The user can specify which path in the file should be associated with the b1 receiver and the disjoint path will automatically be used for the b2 receiver.
Example: A differential probe is used and the .s4p file has dominant paths 1->2 and 3->4 (i.e., the low insertion loss parameters are S21, S12, S43 and S34). The user cables what is nominally port 2 of the probe to the b1 receiver chain. On the network extraction dialog, the user should select 1->2 as the path for the VNA b1 receiver. This will result in S21 being used for embedding/de-embedding on the b1 noise data and S43 will be used on b2 noise data.