A coaxial cable carries current in both the inner and the outer conductors. These current are equal and opposite and as a result all the fields are confined within the cable and it neither radiates nor picks up signals.
This means that the cable operates by propagating an electromagnetic wave inside the cable. As there are no fields outside the coax cable it is not affected by nearby objects. Accordingly it is ideal for applications where the RF cable has to be routed through or around buildings or close to many other objects. This is a particular advantage of coaxial feeder when compared with other forms of feeder such as two wire (open wire, or twin) feeder.