Abstract: The antenna is designed to radiate decimetric or centimetric waves according to an acute angle .theta..sub.o capable of varying by several dozens of degrees. It has the shape of a rectangular parallelepiped having a thickness e, a length L and a width l.sub.t metal-plated over almost its entire surface and containing a material having a dielectric constant .epsilon..sub.r. According to the invention only a band having a fixed width d has not been metal-plated, which band extends substantially in the center over a large face of the antenna, d being equal to several times e, the second large metal-plate face constituting the ground plane. A micro-strip line (26) which crosses the band and contains the antenna feedpoint (31) electrically interconnects the two metal-plated semi-surfaces (28, 29) defined by the non-plated band. The thickness e is of the order of that of a printed circuit board, the length L (L=N+z.sub.a) is more than twice the wavelength .lambda. of the wave to be transmitted and the width l.sub.