Ground Pouring in RF PCB

[MW_Engineer]

In RF board designs, we frequently see each module in the design encapsulated by a narrow ground guard stitched with via holes parallel to RF traces which is nothing but ground pouring.
The basic reason is to reduce electromagnetic emission & coupling.

I want to understand the exact level effect of ground pouring in RF PCB. Can I have the general rule of thumb for following points?

-> When ground pour shoud be used?
-> how close two traces can be placed in parallel?
-> Is it frequency dependant?
-> What distance should be there between trace & ground pour?
-> Vias seperated by lambda/20 is fine or not?

Please guide me.
Thank you

 

[marce]

https://www.jlab.org/accel/eecad/pdf/050rfdesign.pdf
Some basics, if basic can be used as a term with RF:smile:

 

[MW_Engineer]

Dear Marce,

Thanx for the reply. I already have that pdf file but that only mentions the via distance for ground fenceing as lambda/20 but no other thumb of rule is mentioned.

 

[marce]

Lambda/10 is also worth considering, or with todays PCB manufacturing abilities, you can create a co-axial structure on a PCB, by controlled depth milling (either mechanical or laser) and edge plating.


P.S. I have prior art regarding this going back a few years.