Definition - What does Coaxial Antenna mean?
A coaxial antenna is a type of dipole antenna used with an unbalanced feed line connected to the device. A coaxial antenna has a hollow conducting tube through which a coaxial cable passes. Coaxial antennas are mostly used with citizens band (CB) radio at frequencies above 10 megahertz. Coaxial antennas are typically mounted vertically.
Techopedia explains Coaxial Antenna
A coaxial antenna is a dipole antenna, meaning that it has two conductive elements. One side of the element is mounted to a hollow metal tube. The tube functions as an outer conductor. Coaxial cable is passed into this tube and connected. An inner conductor is mounted on top of the tube. A coaxial antenna is typically omnidirectional and can be mounted in any configuration, but the most typical mounting is vertical for the greatest coverage. Coaxial antennas are popular with CB and amateur radio enthusiasts.