A multi-band radio antenna, wherein the radio antenna comprises - a substrate formed of a dielectric material; - a ground plane of electrically conductive material, arranged on a first face of the substrate; - a resonator configured to convert an incident electrical signal into an electromagnetic wave and to resonate at at least two distinct resonance frequencies, the resonator comprising at least three elements (E1, E2, E3) arranged on a second face of the substrate opposite to the first side; wherein a first element is formed by a first strip of electrically conductive material; a second element is formed by a second strip of electrically conductive material; a third element is formed by a third strip of electrically conductive material; the second element is electrically connected to the ground plane by means of a via passing through the substrate at a first end of the second strip; the second element forms an extension of the first element and is electrically connected directly to the first element at a second end of the second strip opposite the first end; the first element is separated from the third element by a slot and electrically connected to the third element at one end of the first strip and one end of the third strip by means of a transition strip of electrically conductive material passing through the slot; the third element is connected to an electrical supply line to receive the incident electrical signal; the first element and the second element are configured to form a quarter-wave resonator with impedance jump, with an impedance jump between the first element and the second element having an impedance greater than that of the first element; and the third element is configured to radiate like a half-wave patch antenna. - a substrate formed of a dielectric material; - a ground plane of electrically conductive material, arranged on a first face of the substrate; - a resonator configured to convert an incident electrical signal into an electromagnetic wave and to resonate at at least two distinct resonance frequencies, the resonator comprising at least three elements (E1, E2, E3) arranged on a second face of the substrate opposite to the first side; a first element is formed by a first strip of electrically conductive material; a second element is formed by a second strip of electrically conductive material; a third element is formed by a third strip of electrically conductive material; the second element is electrically connected to the ground plane by means of a via passing through the substrate at a first end of the second strip; the second element forms an extension of the first element and is electrically connected directly to the first element at a second end of the second strip opposite the first end; the first element is separated from the third element by a slot and electrically connected to the third element at one end of the first strip and one end of the third strip by means of a transition strip of electrically conductive material passing through the slot; the third element is connected to an electrical supply line to receive the incident electrical signal; the first element and the second element are configured to form a quarter-wave resonator with impedance jump, with an impedance jump between the first element and the second element having an impedance greater than that of the first element; and the third element is configured to radiate like a half-wave patch antenna.