Well I was learning transmission but I got a bit confused when I came to coaxial cables transmission at radio frequency. 

What I am lost is how the waves are propagating in the cable, I was thinking that AC current just flows through the conductor just like a normal 2 wire system to the antenna. But the electric fields are not in the direction of the current but is in only between the two conductors (inside, and outside).

Why is this? I am so confused