Hello ,I am building a system that needs to tune the YIG into cavity resonator resonance as shown below and in the attached article.
I want to build a basic lock to my cavity resonator.
Why do I need this carrier supression?
Can I make it work basickly without doing the carrier supression?
Thanks.

 

The carrier voltage suppression is needed because the parameter being sought is the current phase, not the voltage phase. At least that is what I see. And you have been struggling with this circuit for over a year, it seems.

 

Could you elaborate please regarding phase of current ?
To me phase is phase no matter if it’s voltage or current.
Why it’s important ?

 

The Phase and Current relationship varies as resonance is approached and is also related to the SWR. Reflected power is an effect of the voltage and phase relationship, which varies as resonance is approached. That is covered in detail in the engineering transmission lines class . It is also important for power transmission/distribution designs. But not a very exciting part of the class material.