Hi. I'm currently using ENA network analyzer E5071C from Agilent Tech.
I'm trying a TRL calibration to measure SMD components like capacitors, so I've made a test fixture and TRL cal kit.
I don't have any problem with defining Thru and Reflect standards.
But when defining a Line standard, I was advised to put in a delay offset, after measuring the difference of group delay of the Thru and Line standards. This is the part I did not understand, because what I was thinking is that the difference of electrical lengths between the Thru and Line is gonna be automatically calculated by the difference of physical size(length) of each standard. So I wonder if it is necessary to put a delay offset when defining a Line standard. If yes, what is the reason?