Patents by Inventor Yeongming Hwang

Yeongming Hwang has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5576721
    Abstract: 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.
    Type: Grant
    Filed: November 21, 1994
    Date of Patent: November 19, 1996
    Assignee: Space Systems/Loral, Inc.
    Inventors: Yeongming Hwang, Vito J. Jakstys
  • Patent number: 5121129
    Abstract: 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.
    Type: Grant
    Filed: April 25, 1991
    Date of Patent: June 9, 1992
    Assignee: Space Systems/Loral, Inc.
    Inventors: Eu-An Lee, Yeongming Hwang, Vito J. Jakstys
  • Patent number: 4958162
    Abstract: 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.
    Type: Grant
    Filed: September 6, 1988
    Date of Patent: September 18, 1990
    Assignee: Ford Aerospace Corporation
    Inventors: Thomas E. Roberts, Yeongming Hwang
  • Patent number: 4903033
    Abstract: 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 hybrid coupler (40) may be used for converting from linear polarization to circular polarization.
    Type: Grant
    Filed: April 1, 1988
    Date of Patent: February 20, 1990
    Assignee: Ford Aerospace Corporation
    Inventors: Chich-Hsing Tsao, Yeongming Hwang, Francis J. Kilburg, Fred J. Dietrich
  • Patent number: 4847625
    Abstract: 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.
    Type: Grant
    Filed: February 16, 1988
    Date of Patent: July 11, 1989
    Assignee: Ford Aerospace Corporation
    Inventors: Fred J. Dietrich, Chich-Hsing A. Tsao, Yeongming Hwang, Francis J. Kilburg
  • Patent number: 4355316
    Abstract: This specification discloses a microwave antenna system using an offset J-hook feed to achieve low sidelobe energy level over the entire radiation space from an electrical circular reflector antenna. An electromagnetic horn is positioned along the central axis of symmetry of a parabolic reflector. A waveguide feed is coupled to the horn and intersects the reflective surface at a position offset from the axis of symmetry.
    Type: Grant
    Filed: September 22, 1980
    Date of Patent: October 19, 1982
    Assignee: Ford Aerospace & Communications Corp.
    Inventors: Yeongming Hwang, Ching C. Han, David F. Ford
  • Patent number: 4343005
    Abstract: The antenna system employs a parabolic reflector fed by an offset feed array of circular wave guides located substantially at the focus of the parabolic reflector, but offset from the axis thereof. A plurality of aperture tuning mechanisms disposed at the mouths of the circular waveguides of the waveguide feed array, and having physical lengths much shorter than one wavelength at the frequencies involved, are provided to reduce cross-polarization and mutual coupling between adjacent feeds. The short resonant length of these tuning mechanisms, and their shape which is chosen to generate the TM.sub.11 mode E-field contour line ensures that they are effective over a broad bandwidth of as much as 20% or more. Within this bandwidth, they act as inductive suppressors to control both cross-polarization and mutual coupling between adjacent feeds.
    Type: Grant
    Filed: December 29, 1980
    Date of Patent: August 3, 1982
    Assignee: Ford Aerospace & Communications Corporation
    Inventors: Ching C. Han, Herman W. Bilenko, Yeongming Hwang