RAK3172 IPEX variant ground plane with P-0205-02 antenna

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?

Consider the PCB antenna P-0205-02 as an evaluation antenna, it doesn’t have the best performance and if you really want a good range there are better options like

  • use an external LoRa antenna
  • design the antenna directly on your PCB (we are offering this as a service)

Example for an antenna design on the PCB itself is our Unify Enclosure mounting plate with integrated antenna: