Abstract: In a reflective angle of a radar, auxiliary elementary sources are positioned beneath the main source. By the division of the measurement signals of the measurement channel of the main source and of the auxiliary measurement channel, a monotonous characteristic is obtained, enabling the elevation angle to be measured with high precision. FIG. 1.

Abstract: Secondary lobe cancellation (SLC) is used to reduce the power of jamming signals received by the sidelobes of a main radar antenna. The signal from the radiation pattern of the main antenna is summed with signals from auxiliary radiation patterns. Each auxiliary pattern is chosen to be directional, to have a null or at least a gain minimum in the direction of maximum radiation in the main antenna pattern, to have its phase center close to that of the main antenna pattern, and to have gain minimums in those directions for which the sidelobes of the main antenna pattern are low enough to be insensitive to jamming signals. The various patterns may all be derived from an array antenna, e.g. a multibeam antenna, an aplanatic lens antenna, or a chandelier fed antenna.

Abstract: An antenna having two crossed cylindro-parabolic reflectors in which the generatrices of said reflectors are orthogonal. The source is placed close to the center of the main reflector, which is further provided with polarization rotation means. The auxiliary reflector is placed facing the main reflector and it is such that it is transparent to a wave polarized linearly in one direction and reflecting to the waves polarized in an orthogonal direction.