Abstract: A three-axis spacecraft including a spacecraft body including first and second opposing radiator/equipment panels, first and second opposing mounting panels, an earth deck and a zenith deck. The zenith deck faces the Earth when the spacecraft is on orbit and the first and second mounting panels face an east and west direction relative to the Earth when the spacecraft is on orbit. The spacecraft further includes a mounting cylinder extending through the spacecraft body and out of the first and second mounting panels.

Abstract: A three-axis spacecraft including a spacecraft body including first and second opposing radiator/equipment panels, first and second opposing mounting panels, an earth deck and a zenith deck. The zenith deck faces the Earth when the spacecraft is on orbit and the first and second mounting panels face an east and west direction relative to the Earth when the spacecraft is on orbit. The spacecraft further includes a mounting cylinder extending through the spacecraft body and out of the first and second mounting panels.

Abstract: A side-fed dual reflector antenna system (10) of the present invention overcomes the size cost and complexity limitations associated with conventional single and multiple reflector antenna systems. The antenna system (10) includes a feed array (18) including separate feeds for generating separate respective antenna beams, a subreflector (20) for reflecting the separate respective antenna beams generated by the separate feeds of the feed array (18), and a reflector (22) having a shaped reflecting surface for reflecting the separate respective antenna beams received from the subreflector (20) toward a terrestrial target (16) to produce substantially contiguous flat beams, each of which provides substantially uniform coverage within a predetermined coverage area on the terrestrial target.

Abstract: A side-fed dual reflector antenna system (10) of the present invention overcomes the size cost and complexity limitations associated with conventional single and multiple reflector antenna systems. The antenna system (10) includes a feed array (18) including separate feeds for generating separate respective antenna beams, a subreflector (20) for reflecting the separate respective antenna beams generated by the separate feeds of the feed array (18), and a reflector (22) having a shaped reflecting surface for reflecting the separate respective antenna beams received from the subreflector (20) toward a terrestrial target (16) to produce substantially contiguous flat beams, each of which provides substantially uniform coverage within a predetermined coverage area on the terrestrial target.

Abstract: Pre-amplification software-based linearization of a signal that is subsequently distorted by a nonlinear amplifier to produce a signal having reduced intermodulation distortion. The predistortion that reduces the intermodulation distortion is obtained by processing the original signal using an algorithm that is based on the characteristics of the nonlinear amplifier. Exemplary processing apparatus comprises circuitry that digitizing an input signal. A software linearizer processes the digitized signal to produce a pre-distorted RF signal. Circuitry is provided that converts the pre-distorted RF signal to an analog signal. A nonlinear amplifier amplifies the pre-distorted analog signal to produce an output signal corresponding to the input signal that has reduced intermodulation distortion. An exemplary processing method comprises the following steps. An input signal is digitized.

Abstract: A post-amplification linearization technique for processing a signal distorted by a nonlinear amplifier. The post-amplification linearization technique is implemented using a linearizer and linearization method and involves processing the distorted signal using nonlinear processing to reduce intermodulation distortion. The nonlinear processing reduces the intermodulation distortion by applying an integral transformation to the nonlinear amplifier characteristic.

Abstract: The integration of traveling wave tube amplifiers and multiplexers onto passive transmit array antenna panels deployed out board of a spacecraft bus to simultaneously provide a spacecraft transponder that permits antenna pattern flexibility in orbit, high DC to RF power conversion efficiency, facilitates higher spacecraft power and provides a spacecraft with deployed payload panel architecture having multiple independent beams that can be electronically reconfigured on the ground or in orbit.

Abstract: An active phased array is provided that includes a plurality of subarrays (20) having an upper RF radiating panel assembly (22) including a plurality of radiating waveguides (26) and a feed waveguide (24) all formed of aluminum. RF radiating slots (28) are cut into one wall of each of the radiating waveguides and a silver-quartz mirror (42), with corresponding slots (44), is bonded to the outside surface. The array further includes a non-RF radiating lower aluminum support panel assembly (34) with a silver-quartz mirror (46) bonded to the outside face. The mirrors efficiently radiate thermal energy in the presence of sunlight. An active electronics module (30) is mounted in an aluminum housing, and includes an RF probe (56). The module 30 is supplied with RF signals, control signals and DC bias voltage over transmission lines contained in a multilayered circuit board (32). RF energy emitted by the probe is coupled from the feed waveguide to the radiating waveguides.

Abstract: According to the present invention, a thin, lightweight active phased array antenna panel is provided that efficiently radiates heat and arbitrarily polarized microwave signal power. The active array panel also efficiently reflects solar power so as to minimize solar heating. The active array panel includes a plurality of subarray elements each of which includes a plurality of aperture coupled patch radiators. The exterior surface of the subarray element is covered with silvered second surface mirrors to provide efficient radiation of heat in the presence of sunlight. A microstrip feed network in the subarray element is embedded in a dielectric material with a high thermal conductivity to efficiently distribute heat. The active array further includes an electronics module for each subarray element. The electronics module contains a solid state power amplifier, phase shifter and associated electronics mounted in a housing made of material with high thermal conductivity.

Abstract: An adaptive antenna comprising at least two sensors for receiving electromagnetic signals and for producing first signals; the antenna further including divider means for dividing each first signal into respective second and third signals; weighting means for modifying each respective second signal according to a quantized weighting function; summing means for summing the respective second signals to provide a fourth signal; means for producing a system feedback signal in response to the fourth signal; limiter means for limiting the dynamic range of the system feedback signal; correlator means for correlating the respective third signals with the limited system feedback signal to produce respective correlator output signals; means for determining the signal environment power level of the far field sensed by the at least two sensors and for providing a fifth signal substantially corresponding to 1/.sqroot.