Abstract: An antenna having one-way circular polarization is of the type comprising a radiating element associated with a frequency filter. It comprises a polarization-selective device disposed at the transition between the frequency filter and polarizer means adapted to cause the wave to be circularly polarized. This multimode selective device is adapted 1) to enable the initial go mode to propagate, 2) in transmission, to pass one of the return modes induced by the polarizer means, and 3) to reflect the other return mode. At the polarizer, the wave made up of the initial mode and of the reflected return modes reinforces the circular polarization of the initial mode. Such an antenna can be made as a single piece of size and weight that are smaller than those of known antennas having one-way circular polarization.

Abstract: A radiating structure, or antenna, includes an exciter patch which receives an excitation signal and a plurality of secondary patches which radiate the waves received from the exciter patch. The structure includes a reflective surface in the vicinity of the exciter patch and the secondary patches constitute semi-reflective surfaces. The combination is such that the waves radiated by the secondary patches are substantially in phase. The distance between the reflective surface and the secondary patches is substantially equal to half the wavelength to be transmitted. The structure maintains the purity of circular polarization over a wide angular sector.