Abstract: An antenna system and method for transmitting or receiving a plurality of pixel beams of satellite communication signals. A focusing device (770) focuses pixel beams on individual antenna elements or horns (708 or 808) of the transmitter (700) or receiver (800). In the transmitter, each antenna element transmits a pixel beam, and in the receiver, each antenna element has focused on it an individual pixel beam.

Abstract: An apparatus (800) and method (1000) for forming a shapeable and directable composite beam (305) from a plurality of pixel beams (302). The apparatus (800) includes a front-end unit (810) which communicates element signals through antenna array elements (808). The apparatus (800) also includes a back-end unit (850) which forms the composite beam from a set of pixel beams by converting between a composite signal and a set of corresponding pixel signals. The back-end unit (850) further adjusts the amplitude and phase of the set of pixel signals to form the composite beam. The apparatus (800) further includes an interconnecting beamforming network (820) interposed between the back-end unit (850) and the front-end unit (810) which couples the back-end unit (850) to the front-end unit (810) by converting between the pixel signals of the back-end unit (850) and the element signals of the front-end unit (810). The method (1100) includes determining a desired shape and direction for the composite beam (1110).

Abstract: A nulling direct radiating array (30) that includes a main phased array (32) and a plurality of auxiliary arrays (70, 72, 74) symmetrically disposed about the main array (32). The main array (32) includes a plurality of antenna elements (34) and a beam forming system (56) that generates one or more channels made up of several pixel beams. The pixel beams from the main array (32) are connected to a nulling processor (108) along with the combined signal from the antenna elements (80) of the auxiliary arrays (70, 72, 74). An adaptive weighting network (112) and an adaptive weight generator (114) within the nulling processor (108) determine whether a jamming signal exists in the channel beam, and weight the pixel beams from the main array (32) accordingly to block the jamming signal. The auxiliary arrays (70, 72, 74) provide a wider beam aperture that is able to more narrowly define the null in the radiation pattern of the main array (32).

Abstract: A light weight parallel plate polarizer (100) employs a sandwich construction design including a polarizer section (102) and a foundation section (104). The polarizer section (102) is formed from low dielectric constant, low density foam or honeycomb layers (112) alternating with polarizer panels (110). The foundation section (104), which supports the polarizer section (102), is formed from a low density, low dielectric constant foundation material. In an alternate embodiment of the present invention, the light weight parallel plate polarizer employs a suspension design (400). The suspension design (400) includes individual sections of dielectric mesh (602) which support polarizer plates (402). The individual mesh sections (602) are suspended between first and second support posts (404, 406) and compression springs (410) may be provided for adjusting and maintaining the tension in the mesh sections (602).

Abstract: A phased array antenna system producing multiple beams that can be rapidly and reliably scanned between desired angular beam locations without the need for highly complex hardware. The antenna system includes multiple antenna elements (30) coupled to frequency converters (34) that downconvert received signals to an intermediate frequency. Each frequency converter (34) receives a local oscillator (36) signal that passes through a phase shifting circuit (40). The phase shifting circuits are adjusted only in a calibration mode, to remove any phase errors, but are not used to select beam locations. In a receive mode, the downconverted received signals are input to a matrix network (44), such as a Butler Matrix, which transforms the antenna signals on its input lines (42) to an equivalent set of beam location signals on its outputs (46), of which there is one for each possible angular beam location of the antenna system.

Abstract: A dual mode horn reflector antenna for providing an antenna pattern having symmetrical beamwidths over a bandwidth of approximately 40%. An input TE.sub.10 rectangular mode signal is provided to the dual mode horn reflector antenna which generates a first TE.sub.11 circular mode signal from the input TE.sub.10 rectangular mode signal. A first TE.sub.10 square mode signal and a first TE.sub.01 square mode signal are generated from the first TE.sub.11 circular mode signal. The first TE.sub.10 square mode signal and the first TE.sub.01 square mode signal are combined generate a resultant signal. The resultant signal is incident upon a reflecting structure which generates an antenna pattern having approximately equivalent beamwidths in perpendicular planes, and reduced sidelobes.

Abstract: A compact radar system includes a dielectric substrate having an upper and lower surface. A ground plane is formed on the upper surface of the dielectric substrate and includes a radiating slot formed therein. A radar transceiver is located below the dielectric substrate and generates transmit signals. A frequency selective surface spaced above the dielectric substrate includes a radiating aperture with a plurality of uniformly spaced holes. The frequency selective surface decreases flow of electromagnetic energy from the radiating slot in one direction towards the transceiver and increases the flow of electromagnetic radiation in an opposite direction away from the transceiver.

Abstract: In accordance with the present invention, a traveling wave coupler generates tracking signals from a circularly polarized microwave signal and includes a waveguide manifold for exciting circular TM.sub.01 and TM.sub.11 modes of said circularly polarized microwave signal. The waveguide manifold includes an input port, a propagation length, and an output port. A coupling arm waveguide includes an auxiliary input port and an auxiliary output port and is aligned and connected to the waveguide manifold along a portion of the propagation length. A coupler located between the waveguide manifold and the coupling arm transforms microwave energy of a TM.sub.01 mode of the circularly polarized microwave signal into a rectangular TE.sub.10 mode in the coupling arm waveguide. The coupling arm waveguide and the coupler generate a difference signal, used to generate the tracking signals, at the auxiliary output port related to the coupled TE.sub.10 mode.

Abstract: The invention relates to a circular polarization (CP) technique and a microstrip array antenna implementing this technique. Using four microstrip radiating elements with proper phasing of the excitation in a 2.times.2 array configuration, the technique averages out the cross-polarized component of the radiation, generating circular polarization of high purity. The technique is broadband and capable of dual-polarized operation. The resultant 2.times.2 array can be used either independently as a CP radiator or as the building subarray for a larger array.