Abstract: The present invention provides a new class of hybrid-mode horn antennas. The present invention facilitates the design of boundary conditions between soft and hard, supporting modes under balanced hybrid condition with uniform as well as tapered aperture distribution. In one embodiment, the horn antenna (100) is relatively simple mechanically, has a reasonably large bandwidth, supports linear as well as circular polarization, and is designed for a wide range of aperture sizes.

Abstract: Methods and apparatus are provided for determining aperture phase distributions for use in radiating signals with an active phased array antenna having multiple beams and multiple carriers. Distinct initial phase distributions corresponding to the carriers are allocated. The initial phase distributions are modified for each of the carriers to generate respective radiation patterns that substantially correspond to respective coverage areas in accordance with amplification and radiation of signals having the initial phase distributions. The modified phase distributions are optimized to simultaneously increase carrier-signal power and reduce an intermodulation product radiated in the respective coverage areas in accordance with amplification and radiation of signals having the modified phase distributions.

Abstract: The present invention relates to an antenna comprising a first antenna array. The first antenna array comprises one or more antenna elements of a first antenna element type in a first region of the antenna array, and a plurality of antenna elements of a second antenna element type in a second region of the antenna array. In one embodiment, the first region of the first antenna array is a central region, and the second region of the first antenna array is a region outside of the central region. In one embodiment, the first antenna array comprises a spacecraft antenna mounted on a spacecraft bus. In another embodiment, the first antenna array comprises a deployed antenna array on a spacecraft.

Abstract: One embodiment of the invention relates to an antenna system, which comprises an antenna array and a calibration system adapted to calibrate the antenna array. The calibration system can calibrate the antenna array in transmit mode, in receive mode, or in both transmit and receive mode. The antenna array includes a plurality of antenna elements and an antenna beamforming system, and the calibration system includes a plurality of calibration probes integrated with the plurality of antenna elements. The calibration probes may be transmit calibration probes, receive calibration probes, or both. In addition, the calibration system includes a calibration processing system adapted to calibrate the antenna array utilizing the interleaved calibration probes. In one embodiment, the calibration processing systems calibrates the antenna array by performing control circuit encoding (CCE) calibration on the antenna array.

Abstract: A phased array antenna design that is modular and scaleable in terms of beam quantity, coverage area, and receive sensitivity/transmit EIRP.

Abstract: A partially deployed antenna array system that provides many beams per array and also reduces the amount of expensive advanced high density packaging that is required. The beamforming circuitry is located on the spacecraft bus, while the frequency converters, amplifiers, and antenna elements are deployed. The antenna array system for a spacecraft comprises a deployed antenna comprising a plurality of antenna elements operable to transmit or receive a radio frequency signal, a beamformer mounted in the body of the spacecraft operable to process a radio frequency signal or an intermediate frequency signal, and a transmission medium operable to communicate the radio frequency signal or the intermediate frequency signal between the beamformer and the deployed antenna. The transmission medium may comprise a fiber-optic link or alternatively may comprise a coaxial cable. The deployed antenna may comprise a plurality of antenna tiles.

Abstract: A means and method to increase the beam traffic capacity, especially in high user density regions, of a multi-beam antenna communication system with multiple signals at any frequency transmitted (received) when in a transmit (receive) mode by canceling interference with neighboring signals. An interference cancellation network is provided for canceling the interference caused by the sidelobe(s) of at least one signal with one or more of the other signals in the network. Each power divider divides its input signal into one reference fractional signal and at least one non-reference fractional signal. Phase shifters/attenuators shift the phase and attenuate the amplitude of at least one of the non-reference fractional signals. Each power combiner combines its input reference fractional signal with at least one non-reference fractional signal into a composite signal emerging from the combiner. The phase/attenuation settings are selected to optimize the signal to interference ratio for each communications link.

Abstract: A phased array antenna design that is modular and scaleable in terms of beam quantity, coverage area, and receive sensitivity/transmit EIRP.

Abstract: A horn for direct radiation or for use as a reflector feed is for operation at disparate frequencies. The horn has a conventionally LSE1,0 distribution at the lower of the two frequencies, and both LSE1,0 and LSE3,0 modes, phased for improved gain, at the higher frequency. The LSE3,0 mode is generated by an H-plane step, and the appropriate phasing, together with improved gain at the lower operating frequency, is achieved by the use of dielectric loading adjacent the E-plane walls of the phasing section of the horn.

Abstract: A means and method to increase the beam traffic capacity, especially in high user density regions, of a multi-beam antenna communication system with multiple signals at any frequency transmitted (received) when in a transmit (receive) mode by canceling interference with neighboring signals. An interference cancellation network is provided for canceling the interference caused by the sidelobe(s) of at least one signal with one or more of the other signals in the network. Each power divider divides its input signal into one reference fractional signal and at least one non-reference fractional signal. Phase shifters/attenuators shift the phase and attenuate the amplitude of at least one of the non-reference fractional signals. Each power combiner combines its input reference fractional signal with at least one non-reference fractional signal into a composite signal emerging from the combiner. The phase/attenuation settings are selected to optimize the signal to interference ratio for each communications link.

Abstract: A system and method to individually characterize all of the antenna elements or amplifiers in an array antenna system simultaneously, without the need to perform sequential measurements. A positioning device allows movement of the antenna with respect to a calibration probe or movement of the calibration probe with respect to the antenna. Multiple simultaneous control circuit encoding (CCE) measurements of each of the array elements in an array antenna are performed. A second aspect of the system and method involves changes in the level of signals transmitted by the amplifiers in the elements of an array antenna system in conjunction with the use of orthogonal coding measurements. Changes in the level of signals transmitted permits simultaneous measurement of the amplifier characteristics of each of the array elements in an array antenna.

Abstract: A horn for direct radiation or for use as a reflector feed is for operation at disparate frequencies. The horn has a conventionally LSE1,0 distribution at the lower of the two frequencies, and both LSE1,0 and LSE3,0 modes, phased for improved gain, at the higher frequency. The LSE3,0 mode is generated by an H-plane step, and the appropriate phasing, together with improved gain at the lower operating frequency, is achieved by the use of dielectric loading adjacent the E-plane walls of the phasing section of the horn.

Abstract: A system and method to individually characterize all of the antenna elements or amplifiers in an array antenna system simultaneously, without the need to perform sequential measurements. A positioning device allows movement of the antenna with respect to a calibration probe or movement of the calibration probe with respect to the antenna. Multiple simultaneous control circuit encoding (CCE) measurements of each of the array elements in an array antenna are performed. A second aspect of the system and method involves changes in the level of signals transmitted by the amplifiers in the elements of an array antenna system in conjunction with the use of orthogonal coding measurements. Changes in the level of signals transmitted permits simultaneous measurement of the amplifier characteristics of each of the array elements in an array antenna.

Abstract: The present invention is a system and method for reducing the transmission of spurious radiation produced by local oscillators (LOs) in a spacecraft-based phased array antenna. The spurious radiation is reduced by spreading a substantial portion of the radiation outside of the earth disk. The spurious LO leakage radiation is spread by adjusting the phase of the LO signal to a specific value in each elemental path such as shifting the phase of the LO signal in every other elemental path by 180 degrees. The phase shifting of the LO signal can be accomplished by various methods, such as the insertion of a transmission line having a length of &lgr;/2 in the LO signal path prior to entering a mixer in every other elemental path, where &lgr; is the wavelength of the LO signal.

Abstract: A choke coupled coaxial connector includes a hybrid transmission line center conductor including an open-circuited transmission line having one-quarter electrical wavelength, which presents an effective short-circuit at a gap in the center conductor structure. The choke coupled connector also includes an open-circuited hybrid transmission line outer conductor also one quarter-wavelength long, which presents an effective short-circuit in a gap in the outer conductor structure. According to an aspect of the invention, certain interior surfaces of the connector are coated with dielectric to prevent galvanic contact and for reduced mating forces. According to another aspect of the invention, the male and female portions of the choke coupled coaxial connector are prevented from rotating. In a particularly advantageous embodiment, an array of choke coupled coaxial connectors.

Abstract: A crossed-slot antenna in a first ground plane has a first feed, in stripline form including a second ground plane, which underlies a portion of one of the orthogonal slots for exciting a first polarization. A conductive lip of the other slot extends through the plane of the first feed, and opens through the second ground plane. A second feed includes conductors underlying the extended other slot. In a preferred embodiment, the feeds for the first and second slots are balanced. In a particularly advantageous embodiment, an array of such crossed slots is co-located with an array of enhanced-gain patch antennas.

Abstract: A near-field calibration arrangement for an antenna array determines the phase shifts or attenuation of the elemental control elements of the array. The calibration system includes a probe located in the near field, and a calibration tone generator. The tone generator is coupled to the probe in the case of calibration of a receive antenna, and to the signal port of the array in the case of calibration of a transmit antenna. A code generator generates sets of values, with each set being orthogonal to the others. The codes are applied to the control input port of the array antenna, so that the codes encode the tone passing through the antenna. The encoded tones are applied to a decoder and processor, which processes the signals to determine the phase shift or attenuation associated with each bit of the control signal. A transmit antenna attitude determination or pointing arrangement uses the calibration tone generator in conjunction with a plurality of remote sites.

Abstract: A near-field calibration arrangement for a phased-array antenna determines the phase shifts or attenuation of the elemental control elements of the array. The calibration system includes a probe located in the near field, and a calibration tone generator. The tone generator is coupled to the probe in the case of calibration of a receive antenna, and to the signal port of the array in the case of calibration of a transmit antenna. A code generator generates sets of values, with each set being orthogonal to the others. The codes are applied to the control input port of the array antenna, so that the codes encode the tone passing through the antenna. The encoded tones are applied to a decoder and processor, which processes the signals to determine the phase shift or attenuation associated with each bit of the control signal.

Abstract: A horn antenna with a cylindrical and an expanded (horn-shaped) waveguide for radiating or receiving polarized electromagnetic waves. The waveguide wall is partially or wholly covered with one or more grids (12) of electrical conducting material with dielectric layers between them. One possible design consists of a tapering (e.g., conical) core (10) of compact dielectric, which allows for the possibility of shaping the terminal surface (13) to a lens which curves the course of radiation in the aperture to the desired radiation graph. Another possible design where the horn wall consists of dielectric covered with metal grids has an especially light construction. The wall surfaces are developed with anisotrope and reactive impedance so that it mainly functions in the same way as a corrugated horn and thus gives low cross-polarizations across a large frequency area. This could be constructed with little weight and could easily be mass-produced.