I am assuming here that the P-0205-02 antenna is ground-plane independent. The antenna plugs directly to the RAK3172 and is mounted about 25mm away from the nearest PCB edge.
If so, the presence of copper fill planes on a nearby PCB may create parasitic effects that may affect antenna tuning.
My usual design practice is to use a 4-layer PCB with dedicated ground and Vdd planes, ground plane fills on the outer layers, and via stitching. I can’t see this is actually needed and may actually be detrimental.
The PCB I am working on has no high-current loads on the PCB other than the RAK3172 module itself. Worst case is a couple of LEDs at <3mA, so it is entirely possible to make a design with no copper fills and minimum track lengths to reduce the potential parasitic effects.
Is there any reason why this would be a bad idea?
