A broadband and multiband antenna of reduced dimension, preferably to be used as external antenna for vehicles is disclosed. The antenna system includes an antenna comprising: a planar ground plane, a planar radiating element having a configuration formed by a central segment and first and second lateral segments extending from the central segment. A feed connection line is connected between the central segment and an edge of the ground plane, and a ground connection line is connected between the central segment and said edge of the ground plane.