I try to implement Multiline TRL Calibration for removing the effect on transmission Line at higher frequency. I found the selection procedure of multiple line lengths for the calibration in here (https://www.microwaves101.com/encyclopedias/trl-calibration).


One thing, they do not mention any reference - so can I rely on this calculation?


Then, as I found in other references, multi-line in TRL helps to cover the higher frequency standards. [That means we can avoid the bad calibration result at higher frequency].

But by using those procedures - the extra line just helps to cover the lower frequency.

Like,
One standard can cover down to 13.75 GHz

Two standards can cover down to 1.72 GHz

Three standards can cover down to 215 MHz

But I want to cover the higher frequency. How can I do this?