Antenna feed for a direct radiating array antenna, radiating panel and antenna comprising several antenna feeds

An antenna feed for a direct radiating array antenna, for the transmission and the reception of microwaves, said feed comprising a waveguide having at least one main part in hollow straight cylinder form extending in a longitudinal direction, the base of said cylinder having at least one axis of symmetry in its plane and the outer transverse dimensions of said main part being constant in the longitudinal direction;

• the main part of the waveguide comprising, in said longitudinal direction:
• a first portion forming a radiating element, or the major part of said radiating element, said radiating element comprising first ridges extending inwards and over all or part of the length of said radiating element, said first ridges being regularly distributed around the perimeter of said radiating element and each having several treads along the longitudinal direction, the number, the heights and the thicknesses of said treads being configured to allow a given variation, preferably an increase, of impedance between an input and an output of the radiating element;
• a second portion forming a polarizer, said polarizer comprising two inputs separated by an internal leaf extending in the longitudinal direction, and an output corresponding to the input of the radiating element, the internal leaf comprising several levels along the longitudinal direction, said levels being configured to transform a circularly polarized electromagnetic field at the input into a linearly polarized electromagnetic field at the output, and, in reverse, to transform a linearly polarized electromagnetic field at the output into a circularly polarized electromagnetic field at the input, the polarizer further comprising second ridges extending inwards and over all or part of the length of said polarizer, said second ridges and said internal leaf being regularly distributed around the perimeter of said polarizer;
• a third portion comprising a filter, the internal leaf being prolonged in all or part of said third portion, the filter comprising a set of frequency filtration posts disposed inside the third portion and on one and the same surface of the internal leaf, the output of the filter corresponding to one of the two inputs of the polarizer, said third portion further comprising third ridges extending inwards and over all or part of the length of said third portion, said third ridges and the internal leaf being regularly distributed around the perimeter of said third portion;
• the radiating element, the polarizer and the filter being made of a single piece, preferably produced by an additive manufacturing technique, and the polarizer and the filter being disposed end-to-end in the longitudinal direction.