Omnidirectional antenna system for radio direction finding

A radio direction finding antenna system including four identical radiating dipoles uniformly distributed on a circle around a conductive mast and designed to determine the angle .theta. of incidence of the propagation direction of a plane electromagnetic wave relative to a reference direction, wherein said radiating dipoles are made of two symmetrical radiating parts and are associated in first and second pairs of diametrically opposite radiating dipoles, the total height of the mast being greater than the length of the radiating elements, each part of a dipole being connected to a conductive wire of a feed line comprising two conductive wires, the dipoles of each pair being inverted relative to each other so as to establish a 180.degree. phase shift between the currents flowing in each of the two dipoles of the same pair, by way of inversion of the wires of the feed lines relative to the parts of the radiating dipoles, and wherein said antenna system includes a processor unit comprising a first two-way in-phase power divider having two inputs for receiving the signals provided by the feed lines connected to the first pair of radiating dipoles and a second two-way in-phase power divider identical to the first and having two inputs for receiving the signals provided by the feed lines connected to the second pair of radiating dipoles, each one of said power dividers having an output, said processor unit comprising a 3 dB-90.degree. type hybrid junction receiving the signals delivered by said power divider outputs and providing two output signals at the same amplitude and a phase difference of 2.theta.-(1/2) .pi. plus a constant, and wherein said antenna system includes calculation means for computing the angle .theta. of incidence on the basis only of the phases of the two output signals of the 3 dB-90.degree. type hybrid junction.

A radio direction finding antenna system including four identical radiating dipoles uniformly distributed on a circle around a conductive mast and designed to determine the angle .theta. of incidence of the propagation direction of a plane electromagnetic wave relative to a reference direction, wherein said radiating dipoles are made of two symmetrical radiating parts and are associated in first and second pairs of diametrically opposite radiating dipoles, the total height of the mast being greater than the length of the radiating elements, each part of a dipole being connected to a conductive wire of a feed line comprising two conductive wires, the dipoles of each pair being inverted relative to each other so as to establish a 180.degree. phase shift between the currents flowing in each of the two dipoles of the same pair, by way of inversion of the wires of the feed lines relative to the parts of the radiating dipoles, and wherein said antenna system includes a processor unit comprising a first two-way in-phase power divider having two inputs for receiving the signals provided by the feed lines connected to the first pair of radiating dipoles and a second two-way in-phase power divider identical to the first and having two inputs for receiving the signals provided by the feed lines connected to the second pair of radiating dipoles, each one of said power dividers having an output, said processor unit comprising a 3 dB-90.degree. type hybrid junction receiving the signals delivered by said power divider outputs and providing two output signals at the same amplitude and a phase difference of 2.theta.-(1/2) .pi. plus a constant, and wherein said antenna system includes calculation means for computing the angle .theta. of incidence on the basis only of the phases of the two output signals of the 3 dB-90.degree. type hybrid junction.