A type of antenna is a device used to transmit and receive radio signals. Dipole antennas, also known as doublet antennas, are two-element antennas consisting of two metal rods connected to a transmission line. AERIAL antennas are antennas that are mounted above the ground, usually on a roof or mast. DISH antennas are parabolic antennas that are shaped like a DISH and are used to focus radio waves in a specific direction.