Antenna with three-dimensional coverage and electronic scanning, of the

Abstract

An antenna of the random spare volume array type comprising a plurality of elementary antennas with almost omnidirectional individual radiation distributed according to a statistically isotropic random relationship of distribution within an enveloping volume having a shape generated by revolution, the mean spacing between elementary antennas being notably greater than a half wavelength of the minimum frequency to be received or transmitted, each elementary antenna being connected to an active module comprising individually controllable phase-shifters themselves connected to a common distributor. According to the disclosure, the elementary antennas are formed by dipoles oriented vertically and supplied by a supply line comprising a first section, extending horizontally between the respective dipole and a common vertical tower coaxial with the enveloping volume having a shape generated by revolution, and a second section extending to the interior of this tower and ending in the distributor. The antenna thus made has a vertical polarization which is advantageous in many examples of use (navy, secondary radars etc.) with, owing to the use of simple dipoles, a very small reflecting surface that makes it very difficult to localize. Furthermore, through this structure, the first sections of the supply lines may easily be self-supporting for the mechanical support of the dipoles on the common vertical tower formed, for example, by a ship's mast.