The question says it all...because i couldn't find a clear cut circuit example on Google

 

The best place where to find it is Google.
I pasted there `
mixer based phase detector circuit` and it gave me this:
https://www.google.lv/search?q=mixe...DiM7ZAhWJFywKHZ9DDhsQ_AUICigB&biw=959&bih=671

Or other words - zillion pages with different constructions.

 

P.S. Actually, I may say how much I want the bad about and habits or politics of our neighbour country at the East, but electronicists they have a just brilliant, thus the Yandex.ru is worth to use if English sites are not useful enough, it is full & overflowing with a different circuitry for each life case.
Thus translate the keywords (for that translate.google.com is designed to be) and apply the Yandex.
I am using the Translit.ru website to get the Kirillica letterset if there is no need for translation, thus I pushed the querry `схема фазового детектора на основе смесителя` and got a:

https://yandex.ru/images/search?tex...ове смесителя&stype=image&lr=11474&source=wiz

You find there a just brilliant circuit examples, as probably You see Yourself.

 

The question says it all...because i couldn't find a clear cut circuit example on Google

Here ya go:
https://www.minicircuits.com/app/AN41-001.pdf

 

Here ya go:
https://www.minicircuits.com/app/AN41-001.pdf

I pick up the schematic from the pdf but this is not detail enough to show what component should involve in the making. I meant what should be on the Phase detector and what is the component involve in the op amp