Question about via for RF PCB design

I don have much experience about PCB.
I would like to know when you design RF PCB,
the more via , the more better ? or it depends ?
Thanks.

It depends.

A via inductance is proportional to its barrel diameter. Its capacitance depends on the anti-via diameter on any planes through which it passes.

You can use parallel vias to reduce path self inductance between the two layers you are connecting. However, you will increase capacitance to the plane layers unless the anti-vias are increased in diameter. You will also create higher probability of coupling to adjacent structures on the board with more vias.

You often will see many ground vias used as a "fence" between two areas of a board that might otherwise be coupled on an RF board. When vias are used in such a manner, you MUST be careful about via-via spacing, or you may create a resonant loop with the vias. The only way to properly make a via "fence" is to model it with simulation software.

Likewise with ground plane "stitching". You will see hundreds of vias used with random placement to connect two ground planes, or a surface copper flood to an internal ground plane. The spacing of those vias can give rise to resonant loops if not done carefully. The only way to be sure is model the structure, and don't use more vias than you need.

The general short answer is - model the structure with a decent simulation package. Don't try to apply "thumb rules". The proper number and diameter of vias isn't something you can accurately guess. Sometimes more is worse than none at Ghz frequencies.

Any reference book ?
Thanks.

Emc & the Printed Circuit Board: Design, Theory, & Layout Made Simple
by Mark I. Montrose

High-Speed Digital Design: A Handbook of Black Magic
by Howard Johnson

The two references above are the best, in my view.

Where can i get the soft copy of these books?

Hello,

Here you go...
https://www.edaboard.com/viewtopic.p...+printed+board
and
https://www.edaboard.com/viewtopic.p...howard+johnson


---manju---