Ford Aerospace Corporation

Space Systems/loral, LLC

Yeongming Hwang

Chich-Hsing A Tsao

Vito J Jakstys

Fred J Dietrich

Francis J Kilburg

Thomas E Roberts

Eu-An Lee

A composite antenna for use in satellite communication provides both the functions of multiple beams and a shaped beam radiated from a single radiating aperture. The radiating aperture may employ a mirror or a lens. Transmitted radiation from an array of radiators is coupled via a subreflector to the main reflector or lens which constitutes the radiating aperture of the antenna system. During reception of radiant-energy signals, signals received by the main reflector or lens are coupled via a separate subreflector to a separate array of receiving radiators operated at a frequency band different from that of the transmit array. The two subreflectors are combined into a single subreflector assembly employing a metallic concave reflector covered by a layer or coating of frequency selective optical material which allows for propagation of radiation at one frequency to the metal reflector while reflecting radiation in the other frequency band from a surface of the coating. Separate beamformers are employed for receiving and transmitting radiant-energy signals, the beamformers combining signals of clusters of radiators to provide for multiple beams wherein each of a plurality of the beams is formed by a cluster of radiators. Additional connection is provided via diplexers to the beamformers to select radiators to be employed for generation of shaped beams for both reception and transmission. The reflecting surfaces have diameters much larger than the diameters of the radiators to provide for individual beams from each of the radiators.

Composite multi-beam and shaped beam antenna system

The EHF omnidirectional antenna system (10) includes a shaped lens (12) that is illuminated by a corrugated horn (14). The lens is disposed in the far-field of the horn and has two shaped surfaces (20 and 30) which together disperse the beam from the horn, such that a nearly uniform coverage over hemispherical coverage area is achieved at a frequency of approximately 44 GHz. The method of making the lens utilizes a surface shaping analysis to develop the shaped surfaces of the lens. A surface matching layer (44) is applied to all surfaces of the lens to reduce surface reflection.

EHF omnidirectional antenna

An antenna for transmitting and/or receiving circularly polarized (CP) electromagnetic radiation throughout a substantial portion of a sphere. A cylindrical waveguide (3,5) is associated with a transmit portion and a receive portion of the antenna, respectively. The outer surface of each waveguide (3,5) is covered with several conductive radiating patches (30,50) equidistant axially and circumferentially arranged. The patches (30,50) may be fed by elongated apertures (51,52) or by coaxial transmission line (41,42). In the former embodiment, CP is present within the waveguide (3,5), while in the latter embodiment, linear polarization is present within the coaxial transmission line (41,42). The individual patches (30,50) radiate CP in a direction normal to the patch (30,50) to produce CP in the broadside direction. The several patches (30,50) arranged in a circularly symmetric fashion working together create, by a process of constructive interference, CP axially, with opposite senses in the forward and reverse directions.

Near isotropic circularly polarized antenna

A microwave-frequency microstrip antenna (10) simultaneously usable for both transmitting and receiving microwave-frequency signals that have dual orthogonally polarized components. The components may be either linearly or circularly polarized. A radiating patch (26) is mounted on a first dielectric (12). A ground plane (20) abuts the first dielectric (12) and has two elongated coupling apertures (32,31) at right angles to each other. A second dielectric (22) abuts the ground plane (20) and has embedded thereon two substantially identical conductive planar feed networks (52,51) that are disposed at right angles to each other. At least one additional optional dielectric layer (16,18) having a conductive patch (36,34) may be interposed between the first dielectric (12) and the ground plane (20) for purposes of broadening the bandwidth of the antenna (10). A meanderline polarizer (45) or a 3 dB 90.degree. hybrid coupler (40) may be used for converting from linear polarization to circular polarization.

Planar dual polarization antenna

A wideband, aperture-coupled microstrip antenna comprising a multilayer structure and including a feed layer, a ground plane including an aperture therethrough, a plurality of tuning layers formed of dielectric material, at least one of the tuning layers including therein a tuning element in the form of an electrically-conductive material, herein called a tuning patch, and final radiating layer including a radiating patch. The multiple tuning layers serve to extend the operational bandwidth of the antenna as compared to other microstrip antennas. Aperture coupling allows realization of the antenna using integrated circuit fabication techniques without the shortcoming of direct physical connections between the feedline and the radiator, and thus providing simple, yet reliable coupling between the feedline and the antenna.

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Los Altos Hills, CA, United States of America

Yeongming Hwang