RF_GND and DC_GND must be connected at some point, otherwise they will have different references and that might burn your circuit. Usually you route your RF signals with reference to RF_GND plane then everything else you reference to some other ground plane, let's call it DC_GND. Finally, connect those 2 ground planes through a big resistor maybe 1/4W 0805, depends on your application. This a method to minimize the amount of noise going from one plane to another plane.
Another way of doing this is to have a RF transformer where you isolate the RF_GND and DC_GND completely. When you choose the RF transformer, make sure to pick the correctly frequency for your application.