Agence Spatiale Europeenne

Space Engineering S.p.a.

Alenia Spazio S.p.a.

Alenia Spazion Spa

Marco Lisi

Raimondo Lo Forti

Antoine G Roederer

Piero Angeletti

Guilio Doro

A digital beam-forming network for an array antenna having N&#x3e;1 antenna ports, to be associated to respective antenna elements, and M&#x2267;1 beam ports (BP), corresponding to respective antenna beams. The digital beam-forming network comprises a plurality of complex weighting elements interconnected through summing nodes. At least one of the complex weighting elements is connected to either two antenna ports, to be associated with respective antenna elements which are arranged symmetrically with respect to the symmetry axis, or two beam ports corresponding to respective antenna beams pointing toward directions which are symmetrical with respect to the symmetry axis, or both. The digital beam forming network can be a part of an array antenna comprising N antenna elements, Nof which are arranged according to an array pattern having a symmetry axis, Nbeing an even integer different from zero.

Digital beam-forming network having a reduced complexity and array antenna comprising the same

Multiple shaped-beam or scanned beams reflector or lens antenna configured so as to have the radiating elements outside the focal plane (imaging) with improved characteristics in terms of gain and coverage area. Said antenna (FIG. 1) essentially consists of a reflector or a lens (1), a certain number of radiators (3) positioned outside the focal plane, a Beam Forming Network (BFN). It classifies in the technical field of multiple shaped-beam antennae and is applicable to radars, telecommunications in general and to space telecommunications in particular. Its most significant advantage consists in its use as transmitter antenna since in it the electric performance/complexity ratio is improved.

Shaped-beam or scanned beams reflector or lens antenna

A multishaped beam direct radiating array antenna has a network on which high power beam forming sub-networks are disposed. The network is interposed between radiating elements and RF power amplifiers. This antenna is in addition constituted with a traditional network in which power combiners, phase shifters and inter-connection lines are provided. The most significant feature is that, with the help of the high power beam forming network, the correct amplitude and phase values, at the radiating element level, may be achieved without differentiating the RF power amplifier output levels, thus keeping its efficiency as high as possible. One of the advantages this configuration presents is the possibility to utilize only one antenna in comparison of the previous techniques in which the same results were obtained utilizing many radiating panels.

Multishaped beam direct radiating array antenna

The invention provides an antenna for transmitting or receiving closely spaced multibeams with very low level sidelobes comprising, for each beam feed, a primary feed feeding one or more main elements surrounded by secondary elements some of which are shared between several adjacent beam feed, the power supplied by the primary feed being distributed to the different elements by means of couplers. According to the invention, each shared element is fed by each of the power transmission lines feeding the main element (E1, E'1) of said adjacent beams through a coupler, each transmission line of a secondary radiating element (L2, L'3) comprising at least two couplers (C1, C2) in series.

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Rome, Italy

Marco Lisi