Abstract: The invention relates to an antenna structure comprising a number of parallel conductors having dimensions and spacings which are small against operating wavelength, and positioned perpendicular to a conducting ground plane; the upper ends of the conductors are terminated by metal plates acting as capacitors against the ground plane, and interconnected by inductive elements, the lower ends of some of said conductors are electrically connected to said ground plane, while another one of these conductors is connected to a power source to impress a voltage between the lower end of said other conductor and said ground plane.