I am trying to measure the permittivity and permeability for PTFE blocks in the X-band frequency range.
I used TRL calibration for my waveguide based measurement. I am wondering how should I apply port extension OR de-embedding to eliminate the errors that caused by the sample holder. For example, my sample holder is about 23mm long ( x-band waveguide), and my sample is about 6mm in thickness and it is placed in the sample holder tightly. How much (in length) do i have to extend for both ports?
Also, do i have to put my sample in the middle of the waveguide?
By the way, I am using PNA E8362C for the measurement.
I did the measurement without port extension/De-embedding, with the PTFE in the middle of the waveguide, the permittivity of PTFE (using NRW method) i got varies with frequency. from 2.4@ 8.4GHz to1.6 @ 12GHz.
I am wondering if the De-embedding will cause such a big problem on the result or maybe there is something wrong with my calibration?