A multi-beam antenna, operating in a single frequency band, having a radio frequency signal input and a radiating antenna surface with a predefined central wavelength, the multi-beam antenna comprising: - at least one layer of dielectric material, with an upper surface and a lower surface opposite to each other, said upper surface constituting the radiating antenna surface; - a metal layer on the lower surface; - said upper surface has a plurality of metal patches, wherein each patch extends for a first respective length along a respective first direction and for a second respective length along a respective second direction; - the patches of said plurality of metal patches are arranged on said upper surface so that: ▪ the distance between consecutive patch centers in any direction is between 0.05 and 0.3 times the predefined central wavelength; ▪ none of the metal patches are electrically connected to any of the other patches; and - the patches belonging to a non-null subset of said plurality of metal patches are such that said first respective length is different from said second respective length; wherein - the antenna is a linearly polarized antenna; - the antenna is a leaky-wave antenna; - the at least one layer of dielectric material is functionally divided into at least four quadrants; - for each of said at least four quadrants, a respective radio frequency signal input system is provided; - the plurality of metal patches is placed around the respective input systems; - said first respective length and said second respective second length are between 0.05 and 0.3 times the predefined central wavelength; - said respective input system is placed at a predefined non-null distance from the metal patches; and - said respective input system is configured to launch a surface wave of the radial type in the layer of dielectric material. - at least one layer of dielectric material, with an upper surface and a lower surface opposite to each other, said upper surface constituting the radiating antenna surface; - a metal layer on the lower surface; - said upper surface has a plurality of metal patches, wherein each patch extends for a first respective length along a respective first direction and for a second respective length along a respective second direction; - the patches of said plurality of metal patches are arranged on said upper surface so that: ▪ the distance between consecutive patch centers in any direction is between 0.05 and 0.3 times the predefined central wavelength; ▪ none of the metal patches are electrically connected to any of the other patches; and ▪ the distance between consecutive patch centers in any direction is between 0.05 and 0.3 times the predefined central wavelength; ▪ none of the metal patches are electrically connected to any of the other patches; and - the patches belonging to a non-null subset of said plurality of metal patches are such that said first respective length is different from said second respective length; wherein - the antenna is a linearly polarized antenna; - the antenna is a leaky-wave antenna; - the at least one layer of dielectric material is functionally divided into at least four quadrants; - for each of said at least four quadrants, a respective radio frequency signal input system is provided; - the plurality of metal patches is placed around the respective input systems; - said first respective length and said second respective second length are between 0.05 and 0.3 times the predefined central wavelength; - said respective input system is placed at a predefined non-null distance from the metal patches; and - said respective input system is configured to launch a surface wave of the radial type in the layer of dielectric material.