Northrop Grumman Systems Corporation

The Boeing Company

Sebong Chun

Sudhakar K Rao

Daniel H Roper

Alan M Taft

Mansoor K Siddique

Christopher S Brown

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.

Compact cross-link antenna for next generation global positioning satellite constellation

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.

Integrated antenna and RF payload for low-cost inter-satellite links using super-elliptical antenna aperture with single axis gimbal

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 2.25:1 frequency band range and provides substantially iso-flux beam density.

Antenna for multiple frequency bands

The present disclosure is directed to an energy extraction device that employs a radioactive isotope, such asSr, as a charged particle source. The decaying radioactive isotope emits energetic charged particles, such as beta particles, into a magnetic field. Because the magnetic field is substantially normal to the paths of the charged particles, a force is induced on the charged particles normal to both the path and the magnetic field. The induced force causes the charged particles to assume circular paths, forming a circulating charged particle beam that is contained within a structure. The circulating charged particle beam emits cyclotron radiation. The structure includes one or more rectennas around the interior wall which convert the cyclotron radiation to electrical energy as a direct current voltage.

Growing community of inventors

Orange, CA, United States of America

Sebong Chun