an antenna with polarization switching comprising a plurality of waveguides fed with radiofrequency signals and perforated with apertures disposed so as to illuminate radiating elements placed on mobile support means in a plane that is distant from the said apertures , it being possible for the said support means to be configured according to at least two distinct configurations . the radiating elements illuminated according to one and the same configuration are adjacent , the support means being adapted for orienting the radiating elements illuminated in a first configuration according to a different direction from the radiating elements illuminated in a second configuration . the antenna applies notably to the switching of antennas onboard objects moving on the ground required to undertake high - speed communications with a satellite , in particular a geostationary satellite .