Insertion Phase Errors in Long Lengths of Coaxial Cable Assemblies

In this section, we will discuss the steps necessary to correct for insertion phase error as part of the calibration procedure for Vector Network Analyzers.

If you have ever tried to measure a long length of cable, you may have noticed the insertion loss (S21,S12) display showing an abrupt change at some frequency in the negative direction or scale. I call this change in transmission loss “cliffing” as if you were looking down a cliff. If not corrected during the calibration stage, this additional loss would add to the total system loss which is erroneous to the actual insertion loss of the cable assembly.