Abstract: An apparatus and method for forming an antenna reflector panel to a desired shape. The apparatus includes a plate having a plurality of threaded holes, wherein a threaded stud is located in each one of the plurality of threaded holes. The tops of the threaded studs define the desired antenna panel contour. Two metal sheets with a honeycomb structure between them are urged against the stud tops by enclosing the fixture and drawing a vacuum therein. After the metal sheets and honeycomb structure have been held in the desired contour for a predetermined time the vacuum is released. The sheet and honeycomb structure are now permanently deformed into the desired shape.

Abstract: A reflector antenna having an adaptive nulling assembly. The assembly comprises a disk shaped mounting plate having a shaft aligned with the rotational axis thereof and passing through the main reflector focusing surface. An absorber of electromagnetic energy is affixed to the disk and a microwave grating of metallic elements is positioned on the surface of the absorber. The amplitude of the nulling signal is controlled by rotating the assembly, and the phase of the nulling signal is controlled by the varying height of the grating above the reflector. Additional nulling elements can be used to null multiple interference sources.

Abstract: An antenna reflector having a parabolically curved reflecting surface is formed of a cellular ceramic material having ceramic fibers fused together in a rigid cellular structure. The body is formed by bonding or fusing a mass of silicon dioxide fibers together at their points of intersection with a fusing agent such as boron nitride in a sintering process, resulting in a fused array of fibers with cellular porosity intentionally distributed through the body to reduce its density. Other types of ceramic fibers can be used either alone or in combination with the silicon dioxide fibers. The antenna reflector finds particular utility in parabolic antennas for satellite microwave communications systems.

Abstract: A dish antenna structure (10) is formed from a plurality of ribs (14) which extend from near the center of the dish to its periphery, and which support antenna panels (18) between them. Each rib has an outer flexible plastic sheath having grooves (44,45) in its side edges which receive the edges of antenna panels (18) and a hollow longitudinal channel (40) within which a rigid support member (42) is fixed. The support ribs (14) and the antenna panels (18) are curved such that the anterior surface of the dish defined thereby is parabolic.

Abstract: A parabola antenna has a parabola surface whose thickness is uniformly decreased from an outer circumferential portion to a central portion of the parabola surface. The thickness of the parabola surface is smallest at the central portion.

Abstract: An antenna reflector comprising a face skin of graphite fiber reinforced epoxy (GFRE) material is coated with a layer of chromium. The chromium is then coated with aluminum and a protective coating of silicon dioxide is then deposited over the aluminum. The chromium has a thickness sufficiently thin to provide good coverage of the pores of the GFRE material and to minimize distortion causing poor bond due to differences in the coefficient of thermal expansion of the different materials in the presence of temperature cycles. The aluminum is sufficiently thick to provide good reflecting characteristics to minimize the polarizing effects of the graphite face skins.

Abstract: Microwave communication and radar systems that employ a blazed microwave reflection grating are disclosed in which the grating comprises an array of electrical conducting scattering elements having plane parallel surfaces that face in the same direction. The plane parallel faces are positioned in parallel equally-spaced planes to provide a generally stair-step, or Venetian-blind type structure. Microwave energy beamed onto the plane parallel surfaces of the array exits at a diffraction-mode angle within the reradiation pattern of the individual scattering elements of the array. Frequency steering of the exit beam in one plane of the array is provided by varying the frequency of the illuminating beam.

Abstract: An antenna (10) and method for fabricating the antenna (10) includes an inner panel (12) with a curved inner receiving surface (14) and an outer panel (16) in coextensive relationship to one another. A plurality of strips (20) having undulations (22) are positioned between the inner (12) and outer (16) panels for interlocking the panels (12, 16) together in predetermined positions to define a composite antenna (10) of substantial strength to present the inner surface predetermined close tolerances over the surface thereof. The undulations (22) of the strip (20) include platform portions (24) for engaging the panels (12, 16) and straight angulated portions (26) interconnecting the platform portions (24). The strip (20) includes raised ribs (30) in the straight portions (26) and hinge portions (28) between the straight portions (26) and platform portions (24) to allow the lateral extent of the strip (20) to increase as the thickness of the strip (20) between the panels (12, 16) is decreased during fabrication.

Abstract: Plastic-made parabola antennas are improved to get more wave gain in the process of manufacture thereof where a wave reflector material is embedded in other molding materials so as not to cause dislocation thereof during thermoset-molding.

Abstract: Support structure for a paraboloid reflector of electromagnetic radiation. The structure comprises a plurality of abutting flat ribs arranged on edge in rotated concentric square patterns, with the ends of inner ribs meeting the sides of adjacent outer squares at forty-five-degree angles. The concave parabolic forward edges of the ribs are aligned at their junctures, establishing the curve of a screen reflector. Corner gussets are positioned on parallel planes that are perpendicular to the focal axis of the paraboloid. The structure is assembled by inserting fasteners through matching holes in the ribs and corner gussets.

Abstract: Antenna structure 10 has a primary reflective surface 12 over which is positioned a subreflector surface 14. Support webs 32, 34 and 36 are made of low dielectric loss insulating material and are adhesively secured in slots in the reflectors. The support webs are positioned on planes through the axis so that the small thickness of the webs is in the projected area and results in an unobstructed and undistorted electromagnetic radiation pattern. The webs firmly support the subreflector in the desired position. The antenna can be configured as a Gregorian system as shown or alternatively as a Cassegrainian system.

Abstract: A deployable spacecraft borne circular reflector structure comprises a plurality of plies of graphite fiber reinforced epoxy (GFRE) fibers, each ply comprising at least two layers of graphite epoxy reinforced fibers having quasi-isotropic properties. A circular ring of multiple layer plies of like construction as the reflector and having a U-shaped cross-section is bonded to the reflector rear surface adjacent the reflector peripheral edge. Each layer of each structure is formed from prepreg graphite fiber epoxy reinforced material.

Abstract: An improved antenna mesh material is made of gold-plated tungsten wire. Because gold-plated tungsten can be drawn to a very fine diameter (less than one mil) it results in a knit mesh having low mechanical stiffness. It also has high electrical conductivity, thereby enhancing its operation as an antenna reflector up to the higher RF frequencies (EHF). In addition, gold-plated tungsten has both sufficient tensile strength and a low coefficient of thermal expansion which enables it to maintain high reflector surface accuracy for changing thermal conditions.

Abstract: A metallic mesh, and a method for its manufacture, for use in making antenna dishes to operate in space at frequencies above 10 GHz. The mesh is formed by making a mesh pattern, photolithographically transferring the pattern onto a sheet of photo-resist coated metal foil, exposing the photo-resist, and then etching the foil. The strands of the mesh have a periodically repeating curved shape to provide a low spring constant resistant to the effects of large temperature changes.

Abstract: The antenna 10 comprises a line of radiating columns 12 extending transversely to the line and a plurality of conducting rods 14 interspersed among the columns 12. The conducting rods 14 are aligned along two lines 22a, 22b to form two reflecting arrays spaced one behind the other with respect to the look direction 11 of the antenna 10. The spacing is one quarter wavelength at the operating frequency.

Abstract: A reflector and a method of making a reflector, the reflector having a dished reflecting surface, a series of slot formations, the extended longitudinal axis of each slot formation being curved and radiating from the center area of the reflecting surface and through the outer edge of the reflecting surface, the material of the reflector laterally of the extended longitudinal axes of said slot formations adjacent at least one end of the slot formations being folded adjacent the extended axes of the slot formations.

Abstract: A triangulated rib structure including first, second and third sets of "egg-crate" interlocking ribs. The first set is oriented in a predetermined direction such as the horizontal or vertical coordinate, and the second and third sets are oriented at angles of first and second senses, respectively, thereby forming triangulated spaces which are inherently rigid. The individual ribs have edges falling adjacent to a desired overall reflector surface, each of these being precut before assembly to provide the required line of curvature as a function of the individual ribs placement. Each rib is itself a planar piece, and the "egg-crate" interlocking slot joints may be stabilized with one or more seam welds. A conductive mesh forming the actual contoured reflector surface is conformed to the desired contoured shape and affixed as by tack-welding to the edges of the ribs adjacent the contoured surface.

Abstract: Metallized sheet-form textile materials of synthetic polymers or natural fibres, to which a metal layer has been applied by currentless wet-chemical deposition, are particularly suitable for use as reflectors for electromagnetic waves in the range from 10 MHz to 1000 GHz. In the case of stretched metallized fabrics, the reflecting radiation is partly polarized which can facilitate or improve the recognition of an object by radar beams. By periodically stretching and relaxing the fabric, it is even possible to modulate the reflected microwaves.

Abstract: Stationary antenna structures are disclosed including horizontally disposed elongated members (12) which are streamlined in the horizontal plane to reduce windloading. In the illustrated embodiments these members have a curved upper surface and a flat lower surface (FIG. 3). Vertically disposed members (14) are provided with a circular cross section since the point on the compass from which the wind originates will vary.

Abstract: A lightweight support structure for electromagnetic and light reflectors including at least two rigid compression rings of any diametrical ratio held vertically spaced and parallel by a plurality of rigid vertically extending peripheral columns and two or more flexible cable sets vertically spaced and parallel with the compression rings. Nodes or junctures on the cable sets are adapted to remain fixed in space with respect to the compression rings by a series of tangential and radial cables and thus support rigid vertical internal columns which in turn support the reflector. The internal rigid columns may progressively increase in height from a central hub to the outermost periphery of the compression rings for supporting a reflector dish of parabolic configuration.

Abstract: A parabolic electromagnetic wave reflector is formed of glued together identical sectors of foam plastic, each with a parabolic curve formed by the upper side, and each with joint elements which serve also as stiffening ribs along their radial edges. A reflective surface is applied to the concave sides of the sectors. When the sectors are joined, they combine to form a parabolic dish.

Abstract: A lightweight inexpensive fiberglass antenna dish is disclosed, as well as a method for the manufacture thereof. The dish may be formed by spraying chopped fiberglass and epoxy binder onto the glazed surface of a parabolic mold. An aperture formed on the focal axis of the antenna dish, either at the time of molding or at a later time, accommodates a heavy wall structural tube which extends along the focal axis half-way towards the focal point and which is secured to the dish. Rods secured between the dish surface and the distal end of the tube form triangular shapes in cross-section which rigidify the dish element. The feed unit, such as a horn, is attached to the distal end of the tube and the transmission lines therefore can pass through the tube itself.

Abstract: This specification discloses a microwave antenna system using an offset J-hook feed to achieve low sidelobe energy level over the entire radiation space from an electrical circular reflector antenna. An electromagnetic horn is positioned along the central axis of symmetry of a parabolic reflector. A waveguide feed is coupled to the horn and intersects the reflective surface at a position offset from the axis of symmetry.

Abstract: This invention relates to large reflectors in particular those used for antennas, solar mirrors and the like having a concave reflector surface. The reflector comprises a membrane having a reflective surface, which membrane in its initial planar state is capable of being deformed in all directions in its plane. The reflector is mounted in a gas-tight chamber as one wall thereof and a differential pressure is exerted across the membrane either by way of increased or reduced pressure applied to the chamber. When deformed to concave shape, such deformation may be sufficient to cause permanent deformation of the membrane to its concave shape when it has been stretched beyond its elastic limit and plastic deformation has occurred. The reflector may then be used removed from the gas-tight chamber and when so used is preferably backed with a rigid foam backing.

Abstract: The present invention relates to a foldable antenna reflector, particularly of large dimensions, for example adapted to fit out a telecommunications or direct television satellite.According to the invention, said reflector has a structure comprising a plurality of arms, each of which is articulated at the end of a frame element remote from the axis of the reflector, so that, when said frame elements are in opened out position, said arms project angularly with respect thereto so that said structure forms a sort of cradle in the concavity of which is disposed said opened out supple dish and, when the frame elements are in collapsed position, said arms are folded along the side of said frame elements inside the cradle, so that said structure then forms a sort of bundle of small diameter enclosing said collapsed supple dish.

Abstract: A radio frequency RF reflective surface of randomly deposited conductive roving lifted from the surface of a reflector mold after having been bonded with such as a polyester resin or epoxy resin. The roving in the form of a chopped element layer of fiberglass having a conductive material coating on the fiberglass is deposited from a chopper gun to cover an entire surface in the form desired for RF reflection and then, without interruption, non-conductive roving is used in the chopper gun to build up the necessary thickness and structural strength in the antenna with a bonding resin being simultaneously applied to fix the roving in place in the structure.

Abstract: A novel grid-type corner reflector adapted to direct circularly polarized waves is described, involving critical and uneven grid reflector rod spacings and fed dipole tilt angles, with adaptation for circular passive directors, as well.

Abstract: This specification discloses an apparatus and method for supporting and moving an antenna load when tracking a satellite in a synchronous orbit. The apparatus includes three elongated supports all of which are attached to the antenna with couplings having a two degree of freedom of movement and two of which supports are attached to the ground with couplings having a two degree of freedom of movement. A stabilizing member coupled between the two supports having a two degree of movement connection with the ground rigidifies the support apparatus. Adjusting the longitudinal length of the elongated supporting members permits the antenna to be simply and effectively positioned over a wide angular range.

Abstract: An electrically conducting, electromagnetic wave reflector comprises a knit wire reflecting surface consisting of two superimposed knitted wire meshes. The wire mesh reflector is impregnated with a transparent thermo-setting resin so that the metallic structure is no more than 3 mils from the outer surface of the reflector. The knitted wire mesh permits the fabric to be smoothly stretched over a three-dimensional surface of predetermined shape. The two wire meshes are staggered with respect to each other to reduce the effective size of the openings between the loops of the mesh. A reinforcing structure preferably consisting of two layers of glass cloth impregnated with a thermo-setting resin is utilized to provide a lightweight reflector substantially impervious to environmental corrosion. The resulting structure may be used as an antenna or reflector and is suitable for the microwave region such as the K band.

Abstract: A mount for an earth station antenna includes an hour angle beam suppoting the antenna for pivotal movement of the antenna about an hour angle axis determined by the position of the hour angle beam. An adjustable azimuth strut is connected to the antenna for pivoting the antenna about the hour angle axis. Two pairs of struts pivotally support the hour angle beam at spaced pivot points to permit adjustment of the hour angle axis so that the antenna can be pointed at a satellite. The lower ends of the two pairs of struts are pivotally connected to a foundation on horizontally spaced axes with the lower ends of the pair of struts connected to the lower pivot point on the hour angle beam being spaced farther away from the lower end of the beam than the lower ends of the other pair of struts, so that pivotal movement of the hour angle beam pivots the upper and lower ends of the beam along different arcs.

Abstract: A large dish member for use as a solar collector, radar antenna or the like is mounted on a tripod structure on a first set of bearings which permit rotation about a polar or azimuth axis, and a second set of bearings which permit rotation about an elevation axis. Drive about the elevation axis is achieved by means of a linear actuator with elevation position being sensed by means of a position transducer such as a selsyn. Drive about the polar or azimuth axis is achieved by means of two motors, one for slow drive, the other for fast drive, both of these motors being coupled through a timing belt drive and worm gear reducer to a drive sprocket. The drive sprocket engages a chain which is welded to the rim of an arcuate spoked drive member in the form of a wheel segment, which is fixedly attached to the dish member and mounted for rotation on the support structure. A position selsyn is provided to sense azimuthal or polar position.

Abstract: An electrically conducting, electromagnetic wave reflector comprises a knit wire reflecting surface consisting of two superimposed knitted wire meshes. The wire mesh reflector is impregnated with a transparent thermo-setting resin so that the metallic structure is no more than 3 mils from the outer surface of the reflector. The knitted wire mesh permits the fabric to be smoothly stretched over a three-dimensional surface of predetermined shape. The two wire meshes are staggered with respect to each other to reduce the effective size of the openings between the loops of the mesh. A reinforcing structure preferably consisting of two layers of glass cloth impregnated with a thermo-setting resin is utilized to provide a lightweight reflector substantially impervious to environmental corrosion. The resulting structure may be used as an antenna or reflector and is suitable for the microwave region such as the K band. There is also disclosed a method of constructing such a reflector.

Abstract: A tool is provided for manufacturing parabolic solar reflectors. The tool employs an improved smooth convex parabolic surface terminating in edges remote from the parabolic vertex which are preferably placed under elastic tension tending to draw the edges toward each other. The improved convex surface is a film of plastic coated with chromium metal on its exterior surface. A multiple layered thermosetting plastic reflector support is molded onto the convex surface of the tool. The reflector support is removed from the tool and a layer of aluminum is vacuum deposited onto the interior concave parabolic reflector surface.

Abstract: A device to be used as a guidance system for sonar or radar or similar transmissions in which a dihedral reflector is used in association with part of the earth's surface (land or sea) whereby a trihedral reflector results for such transmissions in which spurious signals are avoided because the earth forms one of the reflective surfaces to thereby remove spurious signals which could otherwise occur with a normal trihedral reflector.

Abstract: A removable mold for forming high frequency antennae, such as a horn-reflector antenna. The removable mold may comprise a paraboloid-cylindrical section and a pair of half cone shells for forming respectively the paraboloid-cylindrical portion and the cone portion of the antenna. In assembling the mold, the shells are secured together and then the cylindrical section is fastened to the assembled shells. After the antenna has been formed, the mold is disassembled by first removing the paraboloid-cylindrical section, thereafter removing one of the shells and then the remaining shell; and all such mold parts being removed via the radiating aperture of the paraboloid-cylindrical portion of the antenna.

Abstract: Fiberglass antenna for reflecting electromagnetic radiation. The antenna includes metal reflecting surface embedded within the fiberglass. The antenna is fabricated in a heated, vacuum injected mold.

Abstract: A method of forming an antenna reflector having a predetermined curved surface by forcing a plate of metal or plastic upon an array of die members of different heights protruding from a die base, for example, coaxially arranged cylinders of proper height with proper spacing on the die base. This process makes the manufacture of the antenna reflector extremely rapid and easy.

Abstract: The invention contemplates a heat-transfer device or heat pipe characterized by integral screen-wick structure providing relatively great contact area between the internal working fluid or condensable medium and the heat input.

Abstract: A solar furnace of dish-shaped configuration for the reflection of solar rays toward a heat exchanger through which passes a heated medium. The reflective surface of the furnace comprises a multitude of mirror elements incorporated into a fiber glass reinforced plastic structure with each of the mirror elements located so as to reflect rays toward a common focus. A wire grid spaces each of the mirror elements during furnace construction. Each of said mirror elements is temporarily supported on a loosely woven fiber glass cloth permitting each element to individually adapt to the curvature of a convex mold. Subsequent application of fiber glass and resin to the thickness desired results in a rigid dish-shaped structure within which may incorporate support components. A method of furnace construction is additionally set forth.

Abstract: A primary antenna reflective structure is supported for pivotal movement in the elevation direction between the zenith and horizontal points. Drive motors via a bull gear rotates the antenna through its permissible travel. Inertia counterbalance is utilized to control the motion of the antenna. That counterbalance comprises a pinion driven by the bull gear. Left and right guides are integral with the pinion and followers are contained within housings and are adapted to be driven by the guides. The followers move in opposite directions and either compress or relax springs which are housed concentric with the guides. The guides comprise either a ball screw or roller screw, and the followers either a ball nut or roller nut.

Abstract: The specification discloses a radar antenna which is fabricated by forming a plurality of elongated flat ribs each having an inwardly curved forward edge. Slots extending normally from the forward or rearward edge are formed along the length of each of the ribs. A plurality of the ribs are oriented vertically and the slots therein are mated with the slots in a plurality of the ribs which are disposed horizontally. The vertical and horizontal ribs are thus interconnected in a rigid lattice network which defines a plurality of rectangular compartments. The inwardly curved forward edges of the ribs in the lattice network define a contoured shape for an antenna reflecting surface. A screen is attached over the forward edges in order to provide a reflecting surface on the radar antenna.

Abstract: This invention relates to the steering of telecommunication antennae, and particularly to the mountings therefor. These mountings are used for supporting an antenna to allow communications to be established with a geostationary satellite i.e., one which is stationary in relation to the earth. The invention provides that the structure associated with the antenna be mounted at three points on the steering mounting, and the latter rests on the ground. That one of these points which is situated at the apex of said structure is provided with a bi-directional joint which allows the antenna to pivot about an axis XX in azimuth and an axis YY in elevation: these axes lying orthogonally to one another in a plane perpendicular to the axis ZZ of the antenna. The bi-directional joint aforementioned is mounted to pivot on the base mounting about the axis ZZ of the antenna itself.

Abstract: An antenna system for single or plural beams providing continuously variable beamwidth selectively in one or both of two orthogonal senses, i.e., azimuth and elevation, for either communications or angle-tracking. The system includes two parabolic cylindrical reflectors, which are respectively a main reflector and a sub-reflector; the reflectors are positioned with the focal axes thereof orthogonally. A point or multibeam (e.g., monopulse) feed is mounted adjacent the main reflector on the focal axis of the sub-reflector in the Airy disc of the system. Beamwidth is controlled using telescoping sections on the main and sub-reflectors to control the size of the surface areas thereof. Simultaneous operation of the telescoping sections of the reflector and sub-reflector provides bidirectional zooming of the beam without distortion while individual operation of the sections of the reflectors permits unidirectional zooming.

Abstract: A circularly polarized antenna having an end fed short length helical conductor within a conductive funnel-shaped reflector is described. A broad beam width and a relatively low axial ratio is achieved by the termination of the short length helical conductor about a conductive disk and by providing a reflector of shallow depth.