Considerations for Ground Plane
Before planning to place the components as well as when you are doing the PCB layout, considerations for ground plane should be kept in mind.
1. Avoid high impedance ground paths to components; thus increase the size of the ground plane as much as you can. An ideal way is to dedicate a whole layer for ground just beneath the decoupling in a multi-layer PCBs.
2. Avoid long ground loops, which in fact act as an antenna and radiate the energy.
3. Do not make the ground line common and terminate to ground. Use dedicated lines for the parallel components to connect to ground. Use separate vias for each ground termination, if there is a separate ground plane beneath.
4. High-Speed traces nearest reference plane to be solid ground to avoid impedance mismatches and thus avoiding ringing, reflections, undershoots or overshoots due to them. Check the PCB stack-up; if a high-speed signal layer is near to power plane, avoid the plane crossing.
5. Use more than 2 layer PCB for better EMC performance or use ground grids for 2-layer PCB.