S parameter in RF cable

a power of 0dbm is fed to a coaxial cable . this coaxial cable is connected to an antenna. so the power will be sent through the antenna. i know that in RF we could not speak about the voltage. But could someone tell me what is the Voltage and current in the coaxial cable?

As long as there are no standing waves, voltage and current on a transmission line are linked to power by the cable impedance. Calculation rules are the same as for DC.