Radioelectric device for transmitting and receiving radioelectric waves and associated radio altimetry system

A radioelectric device for transmitting and receiving radio waves including a radio wave generator generating radio waves that are frequency-modulated by a predetermined modulation signal and a transceiver antenna system, having a transmission-reception angle with an associated antenna aperture value, able to transmit said transmitted radio wave and receive a radio wave,

• the antenna system comprising a first array of radiating elements able to radiate in a first frequency band and at least one second array of radiating elements able to radiate in a second frequency band, each second array of radiating elements being made up of a regular pad of radiating elements or elementary patches,
• a plurality of activation elements able to activate and/or deactivate each of the first array and second array of radiating elements, each second array of radiating elements being able to be activated or deactivated individually via a said activation element,
• and a control module able to control the activation elements based on a selected antenna aperture value selected from among a discrete set of antenna aperture values, each antenna aperture value of said discrete set corresponding to an activation/deactivation configuration of said first and second arrays of radiating elements.