Examples disclosed herein relate to a phased array antenna system for use with a Low Earth Orbit (“LEO”) satellite constellation. The phased array antenna system has a plurality of antenna panels positioned in a dome and an antenna controller to control the plurality of antenna panels, the controller directing a first antenna panel to transmit a first signal and a second antenna panel to transmit a second signal to a LEO satellite, the first signal having a first phase and the second signal having a second phase different from the first phase.

Embodiments of the present invention comprise a signal processing method and apparatus for use in a satellite payload in which an input RF signal received at a receiver antenna is modulated by using a single optical carrier at the input of an optical modulator. The optical domain signal is processed and is subsequently combined with a single unmodulated optical LO tone to provide an output RF signal for radiation by a transmitter antenna or for further digital processing by an on-board processor. This results in a clean generation of the frequency-converted RF signal at the output of the opto-electrical conversion stage.

Modular antennas with high instantaneous bandwidth are described. In one embodiment, an antenna comprises a plurality of antenna modules tiled together and configured to form one metasurface antenna with an array of surface scattering metamaterial antenna elements; and a feed network comprising a plurality of feed points coupled to the plurality of antenna modules to supply the modules with a feed wave.

In an exemplary embodiment, a phased array antenna comprises multiple subcircuits in communication with multiple radiating elements. The radio frequency signals are independently adjusted for both polarization control and beam steering. In a receive embodiment, multiple RF signals of various polarizations are received and combined into at least one receive beam output. In a transmit embodiment, at least one transmit beam input is divided and transmitted through multiple radiating elements, with the transmitted beams having various polarizations. In an exemplary embodiment, the phased array antenna provides multi-beam formation over multiple operating frequency bands. The wideband nature of the active components allows for operation over multiple frequency bands simultaneously.

Methods and systems are described for providing end-to-end beamforming. For example, end-to-end beamforming systems include end-to-end relays and ground networks to provide communications to user terminals located in user beam coverage areas. The ground segment can include geographically distributed access nodes and a central processing system. Return uplink signals, transmitted from the user terminals, have multipath induced by a plurality of receive/transmit signal paths in the end to end relay and are relayed to the ground network. The ground network, using beamformers, recovers user data streams transmitted by the user terminals from return downlink signals. The ground network, using beamformers generates forward uplink signals from appropriately weighted combinations of user data streams that, after relay by the end-end-end relay, produce forward downlink signals that combine to form user beams.

A method and system facilitate communication between a constellation of satellites and a mobile platform-mounted mobile communicator. The method and system may include the use of a first antenna suited for operation using a first frequency band in a first geographic region and a second antenna suited for operation using either the first or a second frequency band in a second geographic region. The method and system may use a controller to determine which antenna to activate based on one or more of a geographic indicator or a signal indicator. The system used by the method to facilitate the communication may have one or more enclosures over the antennas and controller for mounting to a mobile platform.

A method for multibeam coverage of a region of the surface of the Earth includes the generation, by a telecommunications payload embedded on a satellite, of a plurality of radiofrequency beams, called elementary beams; the formation of a plurality of radiofrequency beams, called composite beams, exhibiting footprints on the ground of different sizes, each the composite beam being obtained by the grouping of one or more elementary beams; and the transmission or the reception of data through the composite beams, identical data being transmitted or received through all the elementary beams forming one and the same composite beam.

A method of operating an uplink scheduler as part of a medium access control scheduler on a satellite includes selecting, from a plurality of user terminals, a first number of zero-bandwidth request user terminals from the plurality of user terminals, selecting, from the plurality of user terminals, a second number of non-zero-bandwidth request user terminals from the plurality of user terminals, binning the second number of non-zero-bandwidth request user terminals into a plurality of bins based on a respective bandwidth requirement for each non-zero-bandwidth request user terminal and based on a minimum user terminal grant and allocating, according to a grant allocation algorithm, a respective grant of radio resources in an uplink frame to each user terminal of the plurality of user terminals into a respective bin of the plurality of bins in an order associated with increasing bandwidth needs. A downlink scheduler is also disclosed.

In a general aspect, a communication system comprises a first station and a second station. The first station includes a photonic crystal maser, a laser subsystem, and a tracking subsystem. A photonic crystal structure of the photonic crystal maser is formed of dielectric material and has an array of cavities and an elongated slot. The elongated slot is disposed in a defect region of the array of cavities. The photonic crystal maser also includes a vapor disposed in the elongated slot and operable to emit a target RF electromagnetic radiation in response to receiving an optical signal. The array of cavities and the elongated slot define a waveguide configured to form the target RF electromagnetic radiation, when emitted, into a beam. The second station includes a receiver configured to couple to the beam of target RF electromagnetic radiation.

A ground station processes downlink signals received from respective satellites. The ground station has a plurality of signal conditioning devices each receiving a respective one of the downlink signals and providing a conditioned downlink signal. A plurality of Doppler and/or Delay compensator devices each receive a respective conditioned downlink signal from a respective one of the plurality of signal conditioning devices. The compensator devices conduct Doppler and/or Delay compensation on the received conditioned downlink signal, and provide a compensated downlink signal output. A selector or diversity combiner receives the compensated downlink signal from each of the plurality of Doppler and/or Delay compensators. The selector or diversity combiner selects one of the received compensated downlink signals based on received signal strength of each received compensated downlink signal to provide a selected downlink signal, or diversity combines all of the received compensated downlink signals to provide a diversity combined signal. The selector or diversity combiner provides the selected downlink signal or the diversity combined signal to an eNodeB.