Disclosed is a radio antenna comprising a substrate of dielectric material; a ground plane of electrically conductive material on a first face of the substrate; a resonator for converting an incident electrical signal into an electromagnetic wave and for resonating at at least two different resonant frequencies. The resonator comprises at least three elements, each in the form of strips of conductive material and arranged on a second face of the substrate opposite the first face. A second element is electrically connected to the ground plane by means of a via passing through the substrate at a first end of the corresponding strip, forms an extension of the first element, and is electrically connected directly to the first element at a second end of said strip which is opposite the first end.