Patents by Inventor Sudhakar K. Rao
Sudhakar K. Rao 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).
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Patent number: 11088461Abstract: The present invention provides a petal reflector antenna that comprises a main reflector having a paraboloid shape and a plurality of identical petals, a feed assembly that includes a horn, a wideband junction, a holder, and a hybrid coupler connected to a diplexer and a multiplexer. The petal reflector antenna further comprises a protective radome cover, a horn, a subreflector, and a support station member for quickly and conveniently set up over a desired ground location. The petal reflector antenna can operate simultaneously in the K, Ka, Ku receive, and Ku transmit frequency bands.Type: GrantFiled: March 22, 2021Date of Patent: August 10, 2021Assignee: CUSTOM MICROWAVE INC.Inventors: Clency Lee-Yow, Sudhakar K. Rao, Suzanna Janet LaMar, Philip Elwood Venezia
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Patent number: 10714841Abstract: An antenna system includes: an antenna, the antenna configured to combine the feed elements to form a high gain element beam (HGEB), the system further configured to combine the HGEBs to form a large coverage beam; and a feed array configured to transfer a signal to the antenna, the feed array being defocused from a focal plane of the antenna by a defocus distance, the feed array comprising a number N of feed elements.Type: GrantFiled: November 27, 2019Date of Patent: July 14, 2020Assignee: NORTHROP GRUMMAN SYSTEMS CORPORATIONInventor: Sudhakar K. Rao
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Patent number: 10587055Abstract: An antenna system includes: an antenna, the antenna configured to combine the feed elements to form a high gain element beam (HGEB), the system further configured to combine the HGEBs to form a large coverage beam; and a feed array configured to transfer a signal to the antenna, the feed array being defocused from a focal plane of the antenna by a defocus distance, the feed array comprising a number N of feed elements.Type: GrantFiled: July 8, 2019Date of Patent: March 10, 2020Assignee: NORTHROP GRUMMAN SYSTEMS CORPORATIONInventor: Sudhakar K. Rao
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Patent number: 10135137Abstract: A phased array antenna system including a front-end circuit having a plurality of antenna channels, each including a front antenna element and a rear antenna element, that provides a spatially combined beam. Each antenna channel includes a beam scan phase shifter and a true time delay phase shifter through which the receive signals or the transmit signals propagate. The system further includes a back-end circuit spaced from the front-end circuit and including an antenna receiving the receive signals from the rear elements or transmitting the transmit signals to the rear elements. The back-end circuit further includes an ortho-mode transducer that separates the transmit signal or the receive signal into orthogonally polarized signals, and a pair of couplers and a pair of polarization phase shifters that combine to adjust the polarization of the transmit signal or the receive signal. The spatially combined beam is reconfigurable in beam shape and its location.Type: GrantFiled: February 20, 2015Date of Patent: November 20, 2018Assignee: Northrop Grumman Systems CorporationInventors: Sudhakar K. Rao, Arun K. Bhattacharyya
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Patent number: 9972897Abstract: A phased array antenna including a plurality of antenna element units mounted to a panel having a first side and a second side. Each antenna unit includes a step aperture integrated radiating (STAIR) antenna element mounted to the first side of the panel and having an outer cylindrical waveguide, a septum polarizer including a plurality of steps and a septum feed structure, and a right hand circularly polarized (RHCP) feed structure electrically coupled to the septum feed structure. Each antenna unit further includes a triplexer module mounted to the second side of the panel and being responsive to a plurality of linearly polarized signals to be transmitted by the STAIR element, where the triplexer module operates to combine the plurality of linearly polarized signals and provide the combined signal to the RHCP feed structure to be converted by the septum polarizer to a circularly polarized signal for transmission.Type: GrantFiled: August 9, 2017Date of Patent: May 15, 2018Assignees: Northrop Grumman Systems Corporation, Custom Microwave Inc.Inventors: Sudhakar K. Rao, Clency Lee-Yow, Philip E. Venezia, Jonathan R. Scupin
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Patent number: 9698492Abstract: A multiple beam integrated antenna system for a satellite including a support structure having an alignment plate. The antenna system further includes a plurality of feed horns mounted to the alignment plate, where each feed horn includes a plurality of tapered sections that support propagation modes for both up-link signals and down-link signals. A septum polarizer is mounted to an input end of each feed horn that converts linearly polarized signals to circularly polarized signals for the up-link signals and converts circularly polarized signals to linearly polarized signals for the down-link signals. A Y-shaped waveguide is coupled to each of the polarizers and includes separate receive reject and transmit reject filters so as to keep the up-link signals and the down-link signals from interfering with each other. Flex waveguides couple the transmit leg and the receive leg of each Y-shaped waveguide to RF modules.Type: GrantFiled: January 28, 2015Date of Patent: July 4, 2017Assignee: Northrop Grumman Systems CorporationInventors: Sudhakar K. Rao, Daniel H. Roper, Arun K. Bhattacharyya
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Patent number: 9666948Abstract: An inter-satellite cross-link antenna for a communications satellite in a constellation of satellites in earth orbit. The complete cross-link system is an array of eight quadrifilar helix antennas with a new design which is eight times smaller than previous designs, and has superior inter-satellite communications performance. The quadrifilar helix antenna is designed with a length, diameter, helix pitch angle and ground plate connectivity which is matched to the UHF inter-satellite communication frequency to provided a toroidal radiation pattern with high signal strength in a direction normal to the antenna axis and very low signal strength in an axial direction. The array of eight quadrifilar helix antennas does not require interleaving with the L-band GPS antenna aperture on the satellite, and does not block or interfere with the earth-directed GPS signals.Type: GrantFiled: February 2, 2016Date of Patent: May 30, 2017Assignee: Northrop Grumman Systems CorporationInventors: Sudhakar K. Rao, Sebong Chun
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Patent number: 9590299Abstract: A dual-reflector inter-satellite link (ISL) subsystem, for a communications satellite in a constellation of satellites in low earth orbit or medium earth orbit. The ISL subsystem includes a main antenna reflector which uses a single-axis gimbal to steer the main reflector only in the elevation plane. An antenna subreflector, a horn and RF feed circuitry are stationary with respect to the host satellite. The main reflector has a super-elliptical design which provides a beam shape which requires no steering in the azimuth plane, while meeting ISL signal strength requirements. By steering the main reflector only, and only in the elevation plane, the disclosed ISL subsystem delivers significantly lower size, mass, complexity and cost, and significantly greater reliability, than traditional ISL systems.Type: GrantFiled: June 15, 2015Date of Patent: March 7, 2017Assignee: Northrop Grumman Systems CorporationInventors: Sudhakar K. Rao, Daniel H. Roper, Alan M. Taft, Sebong Chun, Christopher S. Brown, Mansoor K. Siddique
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Publication number: 20160365630Abstract: A dual-reflector inter-satellite link (ISL) subsystem, for a communications satellite in a constellation of satellites in low earth orbit or medium earth orbit, is disclosed. The ISL subsystem includes a main antenna reflector which uses a single-axis gimbal to steer the main reflector only in the elevation plane. An antenna subreflector, a horn and RF feed circuitry are stationary with respect to the host satellite. The main reflector has a super-elliptical design which provides a beam shape which requires no steering in the azimuth plane, while meeting ISL signal strength requirements. By steering the main reflector only, and only in the elevation plane, the disclosed ISL subsystem delivers significantly lower size, mass, complexity and cost, and significantly greater reliability, than traditional ISL systems.Type: ApplicationFiled: June 15, 2015Publication date: December 15, 2016Inventors: SUDHAKAR K. RAO, Daniel H. Roper, Alan M. Taft, Sebong Chun, Christopher S. Brown, Mansoor K. Siddique
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Patent number: 9502780Abstract: An exemplary antenna array has first self-complementary antenna cells, e.g. bowtie antennas, disposed in a first plane in rows and columns. Additional bowtie antenna cells are disposed in a second plane parallel to the first plane and are aligned in corresponding rows and columns. A first stripline disposed between the first and second planes carries RF signals to/from the first and second bowtie antenna cells. A slot feed couples the RF signals between the first stripline and each of the first and second bowtie antenna cells. A conductive layer in a third plane parallel to the first and second planes serves as a ground plane for signals radiated from/to the first and second bowtie antenna cells.Type: GrantFiled: January 15, 2015Date of Patent: November 22, 2016Assignee: Northrop Grumman Systems CorporationInventors: Loc B. Chau, Sudhakar K. Rao, Steven J. Mass, Dana Quincey
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Publication number: 20160248157Abstract: A phased array antenna system including a front-end circuit having a plurality of antenna channels, each including a front antenna element and a rear antenna element, that provides a spatially combined beam. Each antenna channel includes a beam scan phase shifter and a true time delay phase shifter through which the receive signals or the transmit signals propagate. The system further includes a back-end circuit spaced from the front-end circuit and including an antenna receiving the receive signals from the rear elements or transmitting the transmit signals to the rear elements. The back-end circuit further includes an ortho-mode transducer that separates the transmit signal or the receive signal into orthogonally polarized signals, and a pair of couplers and a pair of polarization phase shifters that combine to adjust the polarization of the transmit signal or the receive signal. The spatially combined beam is reconfigurable in beam shape and its location.Type: ApplicationFiled: February 20, 2015Publication date: August 25, 2016Inventors: SUDHAKAR K. RAO, ARUN K. BHATTACHARYYA
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Publication number: 20160218436Abstract: A multiple beam integrated antenna system for a satellite including a support structure having an alignment plate. The antenna system further includes a plurality of feed horns mounted to the alignment plate, where each feed horn includes a plurality of tapered sections that support propagation modes for both up-link signals and down-link signals. A septum polarizer is mounted to an input end of each feed horn that converts linearly polarized signals to circularly polarized signals for the up-link signals and converts circularly polarized signals to linearly polarized signals for the down-link signals. A Y-shaped waveguide is coupled to each of the polarizers and includes separate receive reject and transmit reject filters so as to keep the up-link signals and the down-link signals from interfering with each other. Flex waveguides couple the transmit leg and the receive leg of each Y-shaped waveguide to RF modules.Type: ApplicationFiled: January 28, 2015Publication date: July 28, 2016Inventors: SUDHAKAR K. RAO, DANIEL H. ROPER, ARUN K. BHATTACHARYYA
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Publication number: 20160211585Abstract: An exemplary antenna array has first self-complementary antenna cells, e.g. bowtie antennas, disposed in a first plane in rows and columns. Additional bowtie antenna cells are disposed in a second plane parallel to the first plane and are aligned in corresponding rows and columns. A first stripline disposed between the first and second planes carries RF signals to/from the first and second bowtie antenna cells. A slot feed couples the RF signals between the first stripline and each of the first and second bowtie antenna cells. A conductive layer in a third plane parallel to the first and second planes serves as a ground plane for signals radiated from/to the first and second bowtie antenna cells.Type: ApplicationFiled: January 15, 2015Publication date: July 21, 2016Inventors: Loc B. Chau, Sudhakar K. Rao, Steven J. Mass, Dana Quincey
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Patent number: 9246234Abstract: An exemplary embodiment of an antenna in accordance with the present invention utilizes a sub-reflector and a main reflector with each of them having its own focal-ring type geometry. The antenna cooperates with a signal transmission feed disposed at the center of the antenna axis between the first and main reflectors to emit radio signals towards the sub-reflector. The sub-reflector reflects radio waves towards a main reflector which in turn reflects the radio waves to form the beam pattern emitted by the antenna. The reflecting surface of the sub-reflector is formed by a portion of an axially-displaced ellipse rotated about the antenna axis. The reflecting surface of the main reflector is defined by a section of a parabola rotated about the antenna axis to form a reflecting surface that concavely slopes away from the antenna axis. An embodiment of the antenna provides a wide coverage conical beam with selectable beam peaks that operate over a 2.Type: GrantFiled: September 24, 2013Date of Patent: January 26, 2016Assignee: Northrop Grumman Systems CorporationInventors: Sudhakar K. Rao, Sebong Chun
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Publication number: 20150084821Abstract: An exemplary embodiment of an antenna in accordance with the present invention utilizes a sub-reflector and a main reflector with each of them having its own focal-ring type geometry. The antenna cooperates with a signal transmission feed disposed at the center of the antenna axis between the first and main reflectors to emit radio signals towards the sub-reflector. The sub-reflector reflects radio waves towards a main reflector which in turn reflects the radio waves to form the beam pattern emitted by the antenna. The reflecting surface of the sub-reflector is formed by a portion of an axially-displaced ellipse rotated about the antenna axis. The reflecting surface of the main reflector is defined by a section of a parabola rotated about the antenna axis to form a reflecting surface that concavely slopes away from the antenna axis. An embodiment of the antenna provides a wide coverage conical beam with selectable beam peaks that operate over a 2.Type: ApplicationFiled: September 24, 2013Publication date: March 26, 2015Applicant: Northrop Grumman Systems CorporationInventors: Sudhakar K. Rao, Sebong Chun
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Patent number: 8957821Abstract: A dual-band feed horn having a connection surface configured for connection to a waveguide and a first surface coupled to the connection surface. The first surface has a cylindrical surface with a length and a first diameter chosen to propagate TE11 modes for both a low frequency band and a high frequency band. The horn has a bandwidth ratio of the high-frequency band to the low frequency band in the range of 1.6-4.0. The horn also has a substantially conical surface coupled to the first surface at a first slope discontinuity. The conical surface includes multiple surfaces each having a respective slope and coupled to adjacent surfaces by a respective plurality of slope discontinuities each having a respective diameter. The slopes and diameters are chosen to generate primarily TM1,m modes (m=1, 2, 3, etc.) in the high-frequency band and primarily higher order TE1,n modes (n=2, 3, etc.) in the low-frequency band such that the low frequency band and the high frequency band have approximately equal beam widths.Type: GrantFiled: August 15, 2013Date of Patent: February 17, 2015Assignee: Lockheed Martin CorporationInventors: Sudhakar K. Rao, Chih-Chien Hsu, Gerard J. Matyas
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Patent number: 8514140Abstract: A dual-band antenna system configured to transmit and/or receive microwave beams over two or more frequency bands with substantially similar beam widths and substantially similar sidelobe levels is disclosed. The antenna system includes at least one reflector and at least one feed horn, the horn configured to provide a first efficiency over a first frequency band and lower efficiencies over one or more second frequency bands. The horn includes a substantially conical wall having an internal surface with a variable slope. The internal surface includes one or more slope discontinuities, wherein the slope discontinuities are configured to generate primarily TE1,m modes within the first frequency band and within the second frequency bands and generate TM1,n modes substantially only within the second frequency bands.Type: GrantFiled: February 25, 2010Date of Patent: August 20, 2013Assignee: Lockheed Martin CorporationInventors: Sudhakar K. Rao, Chih-Chien Hsu, Gerard J. Matyas
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Patent number: 8354956Abstract: A antenna system for generating and distributing power among a plurality of non-focused beams is provided The system comprises a reflector having a focal plane and a non-parabolic curvature configured to form the defocused beams. The curvature is configured to create a symmetrical quadratic phase-front in an aperture plane of the reflector. The system further comprises a plurality of feed antennas disposed in the focal plane of the reflector and configured to illuminate the reflector. Each feed antenna is configured to contribute power toward each of the defocused beams. The system further comprises a plurality of fixed-amplitude amplifiers, at least one of which corresponds to each feed antenna.Type: GrantFiled: June 25, 2009Date of Patent: January 15, 2013Assignee: Lockheed Martin CorporationInventors: Gerard J. Matyas, Sudhakar K. Rao, Alan L. Stern, Minh Tang, William J. Taft, Ronald M. Hirschfield
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Publication number: 20120105293Abstract: A horn antenna includes smooth-walls with multiple slope discontinuities. The horn antenna may have more than an octave bandwidth with a 2.25:1 bandwidth ratio to cover the frequencies of 20 GHz, 30 GHz, and 45 GHz, or all the desired bands for military or other communications.Type: ApplicationFiled: June 11, 2008Publication date: May 3, 2012Applicant: LOCKHEED MARTIN CORPORATION, A Maryland CorporationInventors: Chih-Chien Hsu, Sudhakar K. Rao
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Patent number: 8164533Abstract: A horn antenna includes smooth-walls with multiple slope discontinuities. The horn antenna may have more than an octave bandwidth with a 2.25:1 bandwidth ratio to cover the frequencies of 20 GHz, 30 GHz, and 45 GHz, or all the desired bands for military or other communications.Type: GrantFiled: June 11, 2008Date of Patent: April 24, 2012Assignee: Lockhead Martin CorporationInventors: Chih-Chien Hsu, Sudhakar K. Rao