Abstract: A telecommunications system antenna for communicating, in transmission and in reception, with a large area whose position relative to the antenna varies. The antenna has motors (80, 82) for pointing the antenna towards the area and radiating elements (74, 76) associated with a control device for modifying the antenna's radiation pattern according to the relative position of the antenna and the area. When the antenna is installed on a telecommunications satellite, as the antenna moves, the antenna can remain constantly in communication with an area of the Earth covering several hundred kilometers.

Abstract: The invention concerns a telecommunications system in which the Earth is divided into areas (26) within which communications are effected by means of transmit and receive means on a spacecraft, such as a satellite, allocated to communication for a plurality of areas. Areas (2610, 2611, 2612) of a first category (28) are allocated signals having respective polarizations (PD, PG) and carrier frequencies (&Dgr;F1, &Dgr;F2) such that two adjacent areas of the first category are allocated signals having different polarizations or carrier frequencies. Each area of a second category (30) is allocated signals having all the available polarizations and all the available carrier frequencies.

Abstract: Transmit and/or receive antenna comprising an array (10) of radiating elements (12) and a controller for controlling the amplitude and/or the phase of the signals transmitted or received by each element so that the antenna is able to transmit or receive according to a specified pattern. The array (10) comprises an excess number (N+Q) of radiating elements relative to the requirements and the antenna includes a control device for activating the number (N) of elements which is just necessary to meet the requirements. This control device activates a reserve element (12N+1, . . . , 12N+Q) should failure of an active element be detected.