Abstract: A method for designing a shaped dual reflector antenna comprising the initial selection of a hyperboloidal or ellipsoidal reflective surface profile for the main reflector such that the cross-polarization of the contoured output RF signal beam of the resulting antenna structure is reduced.

Abstract: An active transmit phased array antenna system for generating multiple independent simultaneous antenna beams to illuminate desired regions while not illuminating other regions. The size shape of the regions is a function of the size and number of elements populating the array and the number of beams is a function of the number of beam forming networks feeding the array. All the elements of the array are operated at the same amplitude level and beam shapes and directions are determined by the phase settings. The active transmit phased array antenna includes a plurality of antenna elements disposed in a hexiform configuration. Each antenna element is identical and includes a radiating horn capable of radiating in each of two orthogonal polarizations. The horn is fed by a multi-pole bandpass filter means whose function is to pass energy in the desired band and reject energy at other frequencies. The filter means is coupled into an air dielectric cavity mounted on substrate.

Abstract: A frequency independent beam waveguide comprises a row of equispaced identical axisymmetric phase setting means (1), which may be lenses or reflectors, or a combination of both, spaced a distance D apart from each other. The focal length of each phase setting means (1) is D/2. A launcher (2) spaced a distance D away from the first phase setting means (1A) in the row emits a beam of electromagnetic energy in the direction of said row. The phase and amplitude distribution in the cross-section (A) of the beam at the mouth of the launcher (2) is duplicated every other phase setting means (1) along the row (at locations B), independent of the frequency of the launched beam. As a result, the beam propagates along the row.

Abstract: A lossless and matched dual mode network (10) in which the maximum voltage amplitudes (a, b, and c, respectively) appearing at three output ports (11, 12, 13), are preselected and are arbitrary subject only to the constraint that the sum of the squares of any two elements of the set (a, b, c) must be equal to or greater than the square of the third element of this set. The set of complex voltages (A, B, and C, respectively) appearing at the three output ports (11, 12, 13) when an input signal is applied to one of the input ports (1 or 2) is conjugate with the set of output voltages (AA, BB, and CC, respectively) appearing at the three output ports (11, 12, 13) when an input signal is applied to the other input port, which is isolated from the initially selected input port (1 or 2). The network (10), which may be used as a feed network in an antenna (25) system, e.g., as an even/odd mode network, comprises three 90.degree. couplers (31, 32, 33 ) and three phase shifters (41, 42, 43).

Abstract: A reconfigurable dual mode network (10) in which the maximum voltage amplitudes (a, b, and c, respectively) appearing at three output ports (11, 12, 13), are preselected, reconfigurable, and arbitrary subject only to the constraint that the sum of the squares of any two elements of the set (a, b, c) must be equal to or greater than the square of the third element of this set. The set of complex voltages (A, B, and C, respectively) appearing at the three output ports (11, 12, 13) when an input signal is applied to one of the input ports (1 or 2) is conjugate with the set of output voltages (AA, BB, and CC, respectively) appearing at the three output ports (11, 12, 13) when an input signal is applied to the other input port, which is isolated from the initially selected input port (1 or 2). The lossless and matched network (10), which may be used as a feed network in an antenna (25) system, e.g.

Abstract: A confocal parabolic antenna system includes a grid of parallel metallic strips placed in the focal plane of the antenna system. The strips are oriented in the direction of an uplink wave polarization and eliminate the grating lobes at the uplink frequency band by reflecting the energy of the particular spatial harmonic components which give rise to the grating lobes.

Abstract: An antenna system is disclosed comprising a lens and a feed array having several substantially identical feed elements. The antenna produces a coverage pattern of transmitted radiation in the form of a shaped beam. The present invention permits the use of a smaller number of feed elements for a given size of the lens' aperture by means of attenuating the sinusoidal ripple that is present in the shaped beam radiation pattern and caused by the size of the feed elements. A plurality of disks is placed in the focal plane of the lens. The disks are selective with respect to one spatial frequency of the emitted radiation (which is at a constant electromagnetic frequency). The disks may be fabricated of a material which reflects the radiation, a material which absorbs the radiation, or a dielectric material of a certain thickness stipulated herein which changes the phase of the radiation by 90.degree.. By this technique, ripples are substantially removed from the beam pattern.

Abstract: An antenna system is disclosed comprising a paraboloidal reflector and a feed array having several substantially identical feed elements. The antenna produces a coverage pattern of transmitted radiation in the form of a shaped beam. The present invention permits the use of a smaller number of feed elements for a given size of the reflector's aperture by means of attenuating the sinusoidal ripple that is present in the shaped beam radiation pattern and caused by the size of the feed elements. A plurality of disks is placed in the focal plane of the paraboloidal reflector. The disks are selective with respect to one spatial frequency of the emitted radiation (which is at a constant electromagnetic frequency). The disks may be fabricated of a material which reflects the radiation, a material which absorbs the radiation, or a dielectric material of a certain thickness stipulated herein which changes the phase of the radiation by 90.degree..

Abstract: A single microwave-reflective antenna "dish" can be used in combination with a plurality of multiple-beam microwave feed arrays to generate or receive multiple-beam-path microwave radiation in several different frequency bands. Each of the feed arrays may operate in a discrete band of frequencies, with the combined radiations of all the arrays illuminating the reflector along a single axis. The optical system is based on the Newtonian model, such that the radiations from several arrays located off the principal axis may be combined by corresponding frequency-sensitive reflective surfaces located on the principal axis. Each of these reflective surfaces serves to direct the radiations from a single feed array toward the reflective antenna, and reciprocally, to direct radiation from the antenna to the associated feed array.