Abstract: An imaging array fed reflector for a spacecraft is included in a spacecraft payload subsystem. The payload subsystem includes a multi-beam antenna including a reflector, a plurality of amplifiers, and a plurality of radiating feed elements, the feed elements configured as a phased array, illuminating the reflector, operable at a frequency having a characteristic wavelength (?), and configured to produce, in a far field at the reflector, a set of contiguous abutting beams. The amplifiers are disposed proximate to the plurality of radiating feed elements. Each radiating feed element has a respective coupling with at least one respective amplifier of the plurality of amplifiers. Each radiating feed element, together with the at least one respective amplifier, is disposed in a closely packed triangular lattice such that separation between adjacent radiating feed elements is not greater than 1.5?.

Abstract: A spacecraft communications payload includes a beam forming network (BFN), wherein the BFN includes a first feed waveguide and a first set of branch waveguides, each branch waveguide in the first set operating in a frequency band having a characteristic waveguide wavelength ?g1. A proximal portion of the first set of branch waveguides is communicatively coupled with the first feed waveguide. A distal portion of the first set of branch waveguides is communicatively coupled by way of an array of slots with a plurality of radiating elements. A separation distance between adjacent slots in the array is approximately equal to ?g, and the array of slots is configured as a honeycomb-like triaxial lattice. In some implementations, a compact BFN may be configured to simultaneously operate at two different polarizations (“dual-polarized”) and/or frequency bands (“dual-band”).

Abstract: An imaging array fed reflector for a spacecraft is included in a spacecraft payload subsystem. The payload subsystem includes a multi-beam antenna including a reflector, a plurality of amplifiers, and a plurality of radiating feed elements, the feed elements configured as a phased array, illuminating the reflector, operable at a frequency having a characteristic wavelength (?), and configured to produce, in a far field at the reflector, a set of contiguous abutting beams. The amplifiers are disposed proximate to the plurality of radiating feed elements. Each radiating feed element has a respective coupling with at least one respective amplifier of the plurality of amplifiers. Each radiating feed element, together with the at least one respective amplifier, is disposed in a closely packed triangular lattice such that separation between adjacent radiating feed elements is not greater than 1.5?.

Abstract: A spacecraft communications payload includes a beam forming network (BFN), wherein the BFN includes a first feed waveguide and a first set of branch waveguides, each branch waveguide in the first set operating in a frequency band having a characteristic waveguide wavelength ?g1. A proximal portion of the first set of branch waveguides is communicatively coupled with the first feed waveguide. A distal portion of the first set of branch waveguides is communicatively coupled by way of an array of slots with a plurality of radiating elements. A separation distance between adjacent slots in the array is approximately equal to ?g, and the array of slots is configured as a honeycomb-like triaxial lattice. In some implementations, a compact BFN may be configured to simultaneously operate at two different polarizations (“dual-polarized”) and/or frequency bands (“dual-band”).

Abstract: An array of antenna feed elements includes a plurality of horns, each horn having an aperture and configured for transmission of electromagnetic energy therethrough. At least a first horn is configured with an electrically conductive external surface proximate to the aperture, the external surface contoured so as to reduce mutual coupling between the first horn and an adjacent horn. Where the electromagnetic energy is within a radio frequency (RF) band, the external surface is contoured so as to provide an abrupt change in a gap dimension between the first horn and an adjacent horn, the change occurring at a distance behind the aperture of equal to a multiple of one half the characteristic wavelength of the RF band.

Abstract: Electrically large, stepped-wall or smooth-wall, direct-radiating horn antenna apparatus that may preferably be used in satellite spot beam applications. Exemplary electrically large smooth-wall horn antenna apparatus comprises one or more input ports, an electrically large output port, and a smooth-wall or stepped-wall tapered section having a spline-shaped profile extending from the input port(s) to the output port of the apparatus. The spline-shaped profile is preferably monotonic and is preferably configured to generate a spot beam. The spline-shaped profile may be configured to support multiple frequency bands, and dual simultaneous polarization having either linear or circular polarization. The spline-shaped profile is defined by spline knots, and, the knot radii form a nondecreasing sequence. Preferably, the spline-shaped profile comprises a piecewise cubic Hermite interpolating polynomial spline that interpolates the shape of curves between the spline knots.

Abstract: An RF feed element for an antenna system required to comply with a set of specified secondary pattern characteristics is designed by performing a quantitative optimization of the RF feed element directly with respect to the secondary pattern characteristics. The quantitative optimization may include pre-computing a plurality of partial secondary pattern complex field values. Each partial secondary pattern may be associated with an RF feed element modal beamlet. A value of at least one to-be-optimized feature is optimized by iteratively adjusting the value of the to-be-optimized feature(s) within an optimization loop that iteratively computes secondary pattern characteristics and compares them to the specified secondary pattern characteristics.

Abstract: An array of antenna feed elements includes a plurality of horns, each horn having an aperture and configured for transmission of electromagnetic energy therethrough. At least a first horn is configured with an electrically conductive external surface proximate to the aperture, the external surface contoured so as to reduce mutual coupling between the first horn and an adjacent horn. Where the electromagnetic energy is within a radio frequency (RF) band, the external surface is contoured so as to provide an abrupt change in a gap dimension between the first horn and an adjacent horn, the change occurring at a distance behind the aperture of equal to a multiple of one half the characteristic wavelength of the RF band.

Abstract: An RF feed element for an antenna system required to comply with a set of specified secondary pattern characteristics is designed by performing a quantitative optimization of the RF feed element directly with respect to the secondary pattern characteristics. The quantitative optimization may include pre-computing a plurality of partial secondary pattern complex field values. Each partial secondary pattern may be associated with an RF feed element modal beamlet. A value of at least one to-be-optimized feature is optimized by iteratively adjusting the value of the to-be-optimized feature(s) within an optimization loop that iteratively computes secondary pattern characteristics and compares them to the specified secondary pattern characteristics.

Abstract: Electrically large, stepped-wall or smooth-wall, direct-radiating horn antenna apparatus that may preferably be used in satellite spot beam applications. Exemplary electrically large smooth-wall horn antenna apparatus comprises one or more input ports, an electrically large output port, and a smooth-wall or stepped-wall tapered section having a spline-shaped profile extending from the input port(s) to the output port of the apparatus. The spline-shaped profile is preferably monotonic and is preferably configured to generate a spot beam. The spline-shaped profile may be configured to support multiple frequency bands, and dual simultaneous polarization having either linear or circular polarization. The spline-shaped profile is defined by spline knots, and, the knot radii form a nondecreasing sequence. Preferably, the spline-shaped profile comprises a piecewise cubic Hermite interpolating polynomial spline that interpolates the shape of curves between the spline knots.