Abstract: The invention concerns a linearly or circularly polarized antenna, comprising a dielectric substrate and a conductive element fixed on the dielectric substrate and being delimited at its periphery by an edge which confers to this element a double planar symmetry along two perpendicular axes. In one embodiment, the conductive element includes an excitation point located on a first axis and a first pair of slots which extends along the second of the axes from the periphery towards the center of the conductive element. In another embodiment, the conductive element includes an excitation point which is located on a third axis by bisecting the angle formed between the first and second axis and having two pair of slots which extend respectively along the first and second axis, from the periphery towards the center of the conductive element.