The hybrid calibration is a method of taking a pair of distinct 1-port calibrations, together with some additional measurements, to create a new full 2-port calibration. The “hybrid” part of the definition comes in that the two 1-port calibrations may be with completely different connector types, media types, and/or cal algorithms. One example may be a case where it is desired to have Port 1 in coax but Port 2 in waveguide. This is conceptually similar to some of the adapter removal and network extraction discussions in Adapter Removal Calibrations and Network Extraction, but here a little more flexibility is offered on the calibration side. In particular, the through completion step may be a reciprocal device only (thus bringing in SOLR concepts).

Generally the two 1-port cals are performed in advance and the setups saved, typically as an active channel CHX file type. One enters the dialog below and specifies those cal files. Then the “thru” between the two ports is specified using the usual THRU INFO dialog format. In the case of a physical thru, length and loss information is specified. In the case of a reciprocal, a length estimate is requested to simplify root choice.

Also as with the manual calibrations, a .s2p file describing the thru S-parameters can also be loaded and will be used during the hybrid cal. A characterize thru option is available to calculate the thru's s2p file using two previously stored reflection calibrations (one with and one without the thru present).

As with the adapter removal and network extraction procedures, the cal files used here must be based on the same frequency lists (same frequency range and same number of points at least). In this case, the files must both describe full 1-port calibrations.

As an example of the mixed-media case where this type of hybrid calibration is helpful, consider a desired coaxial-waveguide combination reference plane. One could perform adapter removal processing as discussed in Adapter Removal Calibrations and Network Extraction, but there are occasions where in one of the media planes, one can only perform one port calibrations (due to physical arrangement of the hardware, calibration kit availability, or other reasons). For this example (in WR-42 waveguide), a 1-port K calibration was done for one file and a 1-port WR-42 waveguide calibration was done for the other file. These two files were combined using the hybrid calibration dialog and the resulting calibration was used to measure the hybrid device of Figure: Example Hybrid Waveguide-coaxial Measurement. Note that this figure refers to a port 1-3 calibration associated with multiport measurements (see Multiport Measurements), but the algorithm is exactly the same for 2-port systems.