This invention relates to a flat printed antenna for transmission and/or reception of microwave signals of the type that includes particularlya plate of dielectric substratean earth plane formed by a first conductor layer deposited on a first face of the plate of dielectric substrate,a radiating element (30) formed by a second conductor layer deposited on a second face of the plate of dielectric substrate,means of feeding the antennaThis antenna has a fundamental mode, in which it generates a radiation pattern having a maximum in the direction perpendicular to the plane containing the radiating element, and at least one higher mode, in which it generates a radiation pattern with low elevation,According to the invention, the radiating element has at least one slot (31 to 34) allowing the control of the resonance frequency of a chosen higher mode.