I am designing my second RF board (First one had BLE). This board has LoRa Components (SX1257 and SX1301), GPS (MAX-6) and 4G LTE Module (SIM7600). All the components are on top layer (red layer).
My STACKUP is: Layer 1 (Red): Signal layer with Ground copper pour Layer 2: Ground Layer Layer 3: Power and Ground Layer (There are multiple sections for 3V3, 1V8, 4V and the section just below RF traces is Ground) Layer 4 (Blue): Mostly Ground having few signals.
My question is I can pour ground copper on my first layer with via fencing and stitching at a distance of wavelength/20. Should I keep the ground pour separate for LoRa, GPS and LTE module? They will be connected to each other via layer 2. Or I can have a big copper pour covering the top layer as distance with three RF section is sufficient.