Abstract: A scanning antenna with ferrite control comprising a waveguide consisting of top and bottom ferrite layers and an intermediate layer. An array of radiating dipoles situated at the upper surface of the top ferrite layer. A horn structure containing first and second horn elements extending longitudinally along both sides of the array of radiating dipoles. Each horn element has an engaging part, a spacing part, and an inner wall. The spacing parts extending along and spaced from the top ferrite layer forming respective gaps therebetween. Dielectric spacers are provided at both sides of the array of dipoles and placed within the respective gaps. Each horn element is formed with at least one groove extending inwardly from the respective spacing part and longitudinally along the axis of the waveguide. The longitudinal grooves and the dielectric spaces restrict excitement of the parasitic modes in the waveguide and reduce power losses in the antenna.