Flat microwave antenna structure

Claim 1

A very high frequency planar antenna system for receiving or transmitting clockwise and counter-clockwise circularly polarized signals according to the reciprocating principle of the antenna systems, comprising juxtaposed radiating elements and also comprising at least printed line circuit, by means of which radiating elements are fed in-phase from a common connection point as the circuit lines are of equal length and are arranged in a fan-like pattern, characterized in that it is constituted by superposing : a) a first insulating layer (10) in which mini-horns (11) are provided, placed side by side two- dimensionally and having a square section and whose surface is metal-plated ; b) a first feeding network (20) of the suspended substrate type, for receiving (or transmitting) linearly polarized signals of a first type, whilst this first feeding network (20) is constituted by a first micro-strip line circuit deposited on one of the surfaces of a thin dielectric film (19) and is such that the ends of the micro-strip lines constituting same are coupled to first groups of four mini-horns and this first feeding network (20) is further constituted by a second micro-strip line circuit deposited on the other surface of the thin dielectric film (19) such that the ends of the micro-strip lines constituting same are coupled to the second groups of four mini-horns inserted between the mini-horns of the first groups, whilst the common junction points of these two circuits are re-united for constituting the only connecting point of the feeding network (20), and- the line sections of the first and second circuit are arranged in parallel and flow through metal-plated groves provided in the first layer (10) and in : c) a second insulating layer (30) in which are provided mini-waveguides (31) having the same square cross-section as the mini-horns seen from the first network (20), and of a rectangular section at the other end, which mini-waveguides have metal-plated inside surfaces ; d) a second feeding network (40) of the suspended substrate type for receiving (or transmitting) signals whose polarization is linear and perpendicular to that of the signals conveyed by the first network (20), whilst this network (40) is identical with the network (20), but arranged with respect to the latter such that the ends of the lines of the two circuits constituting same are placed perpendicular to the ends of the lines of network (20), whilst the lines of this network (40) run in metal-plated grooves provided in the preceding layer (30) and in : e) a third insulating layer (50) in which are provided mini-waveguides (51) having the same rectangular cross-section as the mini-horns (31) seen from the second network (40), whilst these mini-waveguides (51) have metal-plated inside surfaces and are short-circuited so that its length is exceeded by the thickness of this said third layer. 2. An antenna system as claimed in Claim 1, characterized in that a depolarizing structure is added thereto, chosen for example between a 3 dB phase shifter or also a depolarizer of the known meander type, so that on one of the output terminals of the system formed thus a counterclockwise circularly polarized signal is available, whilst at the same time on the other output terminal of the system formed thus, a clockwise circularly polarized signal is available.