I am designing a 2 layer PCB that doesn't deal with high speed signals or high currents (sensor board communicating over Lora via SPI and I2C) but does have a LoRa (900MHz) RF daughter board to one corner very close to the power source.
My board has ground planes on both sides but also signals on both. I am trying to keep signals to one side as much as possible, but there are some mechanical constraints that tie my hands a little.
So to make the grounding as good as possible, I am adding vias connecting both ground planes as much as I can and eliminate potential ground islands. I am laying them out in a grid with 3mm between the vias and 0.2mm drill.
But I am wondering if both from an electrical engineering point of view, and a cost point of view, is it "the more the better"? Or does adding a lot of ground vias add cost to PCB manufacturing, or is there an EE drawback to adding a lot of ground vias?