Abstract: A radio direction finding antenna system including four identical radiating elements uniformly distributed on a circle around a conductive mast and designed to determine the angle of incidence of the propagation direction of a plane electro-magnetic wave relative to a reference direction, wherein the radiating elements are associated in first and second pairs of opposite radiating elements in which the elements are inverted relative to each other, and wherein the antenna system includes a processor unit comprising firstly a first matched power halver receiving the signals provided by the first pair of radiating elements and a second matched power halver identical to the first and receiving the signals provided by the second pair of radiating elements, and secondly a 3 dB-90.degree. type hybrid junction receiving the signals delivered by the matched power halvers and providing two output signals at a phase difference of 2.theta.-1/2.pi.. The invention is applicable to radio location.

Abstract: A directional radiocommunication array for radiocommunication antennas comprises an array of N adjacent radiating elements connected in series by a main line and spaced by a quarter-wavelength on the main line. The directional array comprises an insulative substrate on a first side of which are disposed along a first direction adjacent radiating elements in the form of thin metal layers, each radiating element comprising a radiating slot which widens in a linear manner to either side of an axis from a short-circuited secondary slot line on this axis perpendicular to the first direction and parallel to a second or main propagation direction. Each radiating element is insulated from an adjacent element by a decoupling short-circuited quarter-wavelength slot line. The main line is a coaxial cable substantially perpendicular to each secondary slot line and having a central core and an outer conductive sheath.