Abstract: An electrostatically figured directional antenna array for deployment in outer space having means for suppressing sidelobe responses. A portion of the reflector surface symmetric about its center is vibrated by electrostatic controls to change the amplitude and phase of the sidelobe signals whereby the latter can be eliminated by passive filters or time averaging circuitry.

Abstract: Disclosed is a solar collector comprising a membrane for concentrating sunlight, a plurality of elongated structural members for suspending the membrane member thereon, and a plurality of control members for adjustably tensioning the membrane member, as well as for controlling a focus produced by the membrane members. Each control member is disposed at a different corresponding one of the plurality of structural members. The collector also comprises an elongated flexible tensioning member, which serves to stretch the membrane member and to thereafter hold it in tension, and a plurality of sleeve members, which serve to provide the membrane member with a desired surface contour during tensioning of the membrane member. The tensioning member is coupled to the structural members such that the tensioning member is adjustably tensioned through the structural members.

Abstract: A multifrequency antenna includes a main reflector for signals in a low frequency band. One or more portions of the main reflector are deformed to provide one or more auxiliary reflectors for signals in one or more higher frequency bands. The feed for the low frequency band is located axially of the main reflector, while the feeds for the higher frequency bands are offset to the side of the low frequency feed. The lateral and axial offsets of the vertex of an auxiliary high frequency reflector from the vertex of the main low frequency reflector and the focal length of the auxiliary high frequency reflector are selected to minimize the degradation of the performance in the low frequency band.

Abstract: There is disclosed herein an antenna, particularly for use at high frequencies such as approximately one gigahertz and above, which is frequency selective. The antenna design allows signals at a given frequency to be preferentially received, as distinguished from broadband reception. The antenna design can be modified for reception of signals of different given frequencies. The antenna comprises a plurality of parabolic sections in the form of concentric rings or segments with each segment being offset axially from the next adjoining segment to thereby provide an antenna which is relatively flat, or having a low profile, as compared to a standard parabolic antenna. The surface of each segment is a segment of a different focal length parabola, but with each parabolic surface being a function of the signal wavelength (or frequency) to be received by the antenna. The antenna may be round, rectangular or have other shapes. Also disclosed are feed and pick-up arrangements for the antenna.

Abstract: In a reflecting mirror antenna unit, the surface of the reflecting mirror is divided into a plurality of parts, and the parts are made different in thickness from one another, for instance, by bonding metal tapes different in thickness thereto, to change the phase distribution on the reflecting mirror, whereby the configuration of the radiation pattern due to the current distribution on the reflecting mirror is readily changed.

Abstract: The present invention relates to a multibeam antenna arrangement having minimal aberration of astigmatism and coma over a wide area of the focal surface of the antenna. The present antenna comprises a plurality of N reflectors arranged confocally in a sequence along a feed axis of the antenna and at least one feed disposed in the vicinity of a focal point on the focal surface. The reflectors and the at least one feed are further arranged to provide an equivalent centered antenna arrangement with the longitudinal axis of the feed corresponding to an equivalent axis of the centered arrangement for eliminating astigmatism. Coma is then eliminated by deforming two of the N reflectors in a predetermined manner.

Abstract: A reflector type radio frequency antenna having: a feed for producing a difference radiation pattern with a cone-shaped null region; and, a reflector having a surface disposed to reflect a portion of the energy in the difference radiation pattern and having the edge disposed in the cone-shaped null region. With such arrangement, since the edge of the reflector is disposed in the null region of the difference radiation pattern such edge is not radiated with energy which could otherwise illuminate such edge, scatter, and thereby generate unwanted side lobes in the free space antenna pattern.

Abstract: The present invention relates to an antenna arrangement which uses a large offset spherical main reflector to communicate with several, spaced-apart, remote locations. Large aberrations caused by the main reflector are corrected by a first subreflector forming a small image of the main reflector at a conjugate image surface and a second subreflector which is disposed at the image location and is shaped to correct for the aberrations caused by the main reflector. Such correction is, to a good approximation, frequency independent and provides aberration free operation at feeds adjacent each other and associated with remote locations having small differential angles of incidence on the center of the main reflector.

Abstract: The present invention relates to a multibeam antenna arrangement having minimal primary aberration of astigmatism and coma over a wide area of the focal surface of the antenna. The present antenna comprises a plurality of N reflectors arranged confocally in a sequence along a feed axis of the antenna and at least one feed disposed in the vicinity of a focal point on the focal surface. The reflectors and the at least one feed are further arranged to provide an equivalent centered antenna arrangement with the longitudinal axis of the feed substantially parallel to an equivalent axis of the centered arrangement for eliminating astigmatism. Primary coma is then eliminated by deforming two of the N reflectors in a predetermined manner.

Abstract: A multiple reflector antenna is disclosed that comprises a main reflector formed of a portion of a rotatively symmetrical surface with respect to a rotation axis, a sub-reflector, at least one auxiliary reflector, and at least one wave source, said rotation axis being parallel to or slightly deviated from an aperture plane. This antenna is characterized by such construction that said sub-reflector and auxiliary reflector intentionally cause distortion of an electro-magnetic field distribution to cancel the distortion generated at said main reflector.

Abstract: A parabolic reflector for microwave antennae which can be assembled from a plurality, for example eight, identical and interchangeable rigid fiberglass panels is shown. The panels have rigidizing ribs formed on their rear surfaces, integrally with each panel and made of the same material, to assure thermal stability and mechanical rigidity. A mounting ring is produced by some of these ribs while others located on the radial margins of the panels incorporate self-indexing devices for automatically lining up the front surfaces of the panels flush with each other, when the reflector is assembled from the rear surface.

Abstract: The present invention relates to an antenna arrangement capable of correcting for astigmatism over a broadband range, the antenna arrangement comprising a main focusing reflector arrangement (10), such as, for example, a Cassegrainian antenna system, a feed arrangement (12) and an astigmatic correction means (14) disposed between the feed arrangement and the main focusing antenna arrangement. The astigmatic correction means comprises a first and a second doubly curved subreflector (18, 16) which are curved in orthogonal planes to permit the launching or reception of an astigmatic beam of constant size and shape over a broadband range. By proper choice of the angle of incidence at each subreflector, cross-polarization and astigmatism of the beam can be canceled simultaneously.

Abstract: An aperture antenna having the improved phase performance of radiated co- and cross-polarization has been found. The present antenna has, at least, a horn for radiating an electro-magnetic wave, and means for focusing the electromagnetic wave. The focusing means is actually implemented by a reflector or a dielectric lens, and is designed so that the phase distribution of an electric field on an aperture plane of the focusing means has the period of .pi./2 and the maximum phase at (2m-1) .pi./8 from the reference plane of one polarized wave in the polar coordinates system on the aperture plane, where m is an integer.

Abstract: A flexible fine lattice-like grid structure is formed by etching a metal foil printed with a pattern of intersecting webs crossing at junction points. The sections of the webs extending between the junction points have a length greater than the shortest between the junction points. The web sections between junction points can be curvilinear or made up of a plurality of angularly disposed rectilinear sub-sections. The shape and length of web sections can be varied to achieve different expansion limits in different directions.

Abstract: A reflector antenna used for radar, etc, has a subreflector so as to give a relatively large aperture diameter for a primary radiator, and to decrease the effect of the outer atmosphere.A subreflector having a different curvature in a vertical plane than a curvature in a horizontal plane is provided whereby an antenna having a different beam width in the vertical plane to that in the horizontal plane is provided even though a primary radiator having a rotationally symmetrical beam is employed.