Antenna and associated measurement sensor

An antenna which comprises four elementary IFA antennae, each elementary IFA antenna comprising a ground plane, a roof, a short-circuit between the ground plane and the roof and an excitation means, the four elementary IFA antennae being distributed around an axis (Oz) in a first set of two IFA antennae having substantially equivalent elementary radiations and a second set of two IFA antennae having equivalent elementary radiations, the excitation means of the four elementary IFA antennae being fed by radiofrequency signals of like amplitude whereof the phases follow a law which is substantially progressive in quadrature by rotation around the axis.