Abstract: The same reflector dish is used to reflect solar energy to a solar collector device and electromagnetic energy in the form of satellite communications to a transducer. Thus, the apparatus can be used as a combination solar energy collector and an antenna for receiving satellite communications.

Abstract: A feedhorn for a satellite dish which is far more efficient picking up the transmitted microwave signal from a satellite so as to permit the satellite dish to be substantially decreased in physical size. The feedhorn is constructed to pick up either the C-Band or the Ku-Band, each in either the horizontally polarized mode or the vertically polarized mode. The feedhorn utilizes dipoles for picking up the microwave signal which are then transmitted by a coaxial cable to a printed circuit board assembly. The received signal from the printed circuit board assembly is then transmitted through a receiver. The selection of the particular band of frequency that is to be transmitted from the feedhorn and the selection of the horizontal mode or the vertical mode is to be accomplished by a remote actuator such as is commonly used with a conventional television receiver.

Abstract: Disclosed is a variable angle conical scanning antenna that employs an offset paraboloidal reflector which is rotated about an axis that extends through the focus of the paraboloid of revolution that defines the reflector. Electromagnetic energy is supplied to the reflector by an antenna feed that is mounted at the focus of the paraboloid of revolution and directed along the axis of rotation. In this arrangement the electromagnetic energy that is reflected from the offset paraboloidal reflector forms an angle between the axis of rotation and the beam of reflected electromagnetic energy that is equal to the angle between the axis of rotation and the focal axis of the paraboloid of revolution that defines the reflector. Thus, conical scanning at a cone angle that is equal to twice the angle between the axis of rotation and the reflected beam of electromagnetic energy is achieved as the offset paraboloidal reflector is rotated. Variable angle scanning (i.e.

Abstract: A device for adjusting the polarization of a rotatable-feed antenna with respect to a reference plane makes use for an angular reference device located near the feed-horn aperture. The angular reference device consists of a tilting mercury switch having spaced contacts bridged by a mass of mercury and rigidly fixed to the feed horn. The adjusting device includes a connector located at the rear of the antenna in a zone which is accessible for adjustment and a multiple-conductor cable establishing an electrical connection between the contacts and the connector in order to provide an electrical link between the angular reference device and a visual display device.

Abstract: An apparatus for maintaining an arbitrary orientation of the polarization of an antenna, such as an airborne microwave antenna, by using antenna pointing information and platform (aircraft) attitude information to position the input/feed signal.

Abstract: An antenna pointing device capable of scanning in two orthogonal directions comprises a fixed source (20) emitting a radio beam (21) and associated with a main offset reflector (10) and a secondary offset reflector (11), together with a set of at least three mirrors (14, 15, and 17) including a first mirror (14) aligned with the secondary reflector (11), and in which the second and third mirrors (15 and 17) are fixed to respective rotary drive mechanisms (16 and 18) for rotating them about two axes (.DELTA., .DELTA.') extending in orthogonal directions. The main and the secondary reflectors (10, 11) and the first and the second mirrors (14, 15) are mechanically fixed to one another in order to constitute a moving assembly. The second mechanism (18) drives both the third mirror (17) and said moving assembly (10, 11, 14, and 15).

Abstract: A gyratory device for mounting a parabolic antenna on a base or frame in which the gyratory part includes a tubular stationary part receiving a motor and drive connections within the tubular part, a sleeve surrounding the tubular part. Adjustable arms are provided to adjust the axis of the gyratory part relative to the rotary axis of the earth and to adjust the angle of the antenna on the sleeve.

Abstract: An angular-diversity radiating system is described for tropospheric-scatter radio links which comprises a paraboloid and two antenna horns in which the distance between the antenna horns is adjustable in order to vary the diversity angle depending on the transmissive characteristics of the troposphere of the link involved to always have the optimal diversity angle under all link conditions.The radiating system includes four wave guides connected to the two antenna horns to permit the use of single and double polarization for both the antenna horns and the use of both the antenna horns, or alternatively only one, for receiving and transmitting signals.

Abstract: A rotation mechanism for a waveguide feeder is disclosed which is applicable to an antenna rotating section of a satellite tracking antenna system and others. The mechanism includes two flexible waveguides which extend parallel to each other. The flexible waveguides are connected at one end to each other and at the other end to an upper waveguide feeder and a lower waveguide feeder, respectively.

Abstract: An antenna system wherein the feed assembly is rotated to provide spatial polarization stabilization with respect to vehicle movement so that orthogonal polarizations can be used simultaneously.

Abstract: A gimbal arrangement for supporting an antenna element steerable in pitch and yaw is shown to include a generally spherical bearing supporting such element, such bearing having a slot formed therein and aligned with the pitch axis to engage a pin affixed to the antenna element and a pitch and a yaw cam assembly independently actuable to steer the antenna element in pitch and yaw.

Abstract: An antenna for detecting or transmitting polarized radiation. The antenna is small in size (i.e., less than one quarter the wavelength of radiation at its resonant frequency) and is formed by a split-cylindrical capacitor which comprises of a pair of curved plate conductors which are curved about an axis of rotation centered on a plane which coincides with the direction of propagation of the polarized radiation. The curved plate conductors are disposed on opposite sides of the plane, facing each other and are separated by a gap through which the plane extends.

Abstract: A method and apparatus are provided for transmitting a microwave signal as a beam having a wavelength small as compared to the size of the reflecting surfaces, wherein a main reflector is stationary with respect to a sub-reflector and the main reflector is motional with respect to the feed. The invention comprises rotating the sub-reflector about a first rotational axis transverse and preferably orthogonal to the guide axis, the first rotational axis being on the vertex of a secondary reflector, thereby directing radiation from a fixed feed to the motional sub-reflector. The primary reflector and sub-reflector are disposed relative to one another to share a common focus or confocal point.

Abstract: Elements of a radar antenna are provided with one or more electromagnetic actuators capable of moving the elements (scanner or parabolic reflector), independently of the support system in response to electrical signals applied to the coils of the electromagnetic actuators.

Abstract: A double grid reflector antenna for radiating different signals having pure linear orthogonal polarization comprises a couple of identical and superposed reflecting grids. One of said grids has been rotated its boresight to disengage its focus from that of the other, and feeds are set in the focal plane of the respective grids. The front grid reflects indifferently either horizontal or vertical polarization, while transmitting the orthogonal polarization to be reflected by the rear grid.

Abstract: The multiple feed antenna comprises a primary focussing element and at least two feeds. The feeds are spaced from each other and have different characteristics such as different frequency bands. The focussing element is moved such that its focal point coincides individually with the feeds. The focussing element may be designed to be offset with respect to its focal axis. In this manner, the antenna may have a common aperture and common boresight for each of the feeds.

Abstract: A thin sheet is formed into a surface having compound curvature by vacuum forming the sheet against an array of support posts which have been adjusted to define the locus of the desired surface. A rigid frame is placed on the exposed back surface of the sheet and bonded thereto while the vacuum formed shape is maintained. Alternatively, a frame of beam members kerfed to make them compliant is placed on the back surface and bonded to the sheet which restores the structural integrity of the beams by briding the kerfs.

Abstract: A beam scanning antenna system that uses a small, rapidly rotatable feed enna to illuminate a large, fixed secondary collimating device, such as a reflector or electromagnetic lens, which in turn illuminates a large, fixed primary collimating device. The primary collimating device forms a narrow collimating beam that is reflected or transmitted into space. Rotation of the small feed antenna causes the beam to scan.

Abstract: An antenna system having a main reflector, a sub-reflector, and a plurality of horns for radiating different frequencies includes a beam waveguide system which cancels cross polarization otherwise inherent in the system. If the antenna system uses a non-rotationally-symmetric sub-reflector the cross polarization caused thereby is cancelled by the beam waveguide system having at least two focusing reflectors and selected parameters. Alternatively the beam waveguide system can be used with a rotationally symmetric and stationary sub-reflector by being positioned to reflect said beam on the axis of the main reflector. Either the horns or the focusing reflectors may be rotatably switched, the other group being stationary.

Abstract: An apparatus for rapidly starting and stopping a conical scan antenna beam in which a feed rotating about a centerline provides a non-conical scan antenna beam during a search mode. When a target is detected a solenoid moves an actuator pin which displaces one end of the feed from the centerline providing a conical scan antenna beam for target tracking.

Abstract: An arrangement for determining the rotational position of the rotor of an electrical gyroscope is shown to include:(a) at least one sensor including a Hall effect crystal having a rotating magnetic field applied thereto, such field being synchronous with the field causing rotation of the rotor;(b) a phase-lock loop, responsive to square wave signals corresponding to signals out of the Hall effect crystal and a voltage-controlled oscillator to provide a signal approximating the rotational position of the rotor; and(c) a phase detector, responsive to negative going transitions of the square wave and to reference pulses to synchronize the rotational position of the rotor with the reference pulses.

Abstract: This invention relates to an antenna system for a jamming transmitter which is intended to protect a remote object which is remote from the jamming transmitter as well as itself or an object in the immediate vicinity of the jamming transmitter. Known jammer antennas for this purpose radiate either a pencil beam which presents considerable problems in the alignment and orientation and tracking in two planes or alternatively such known antennas are designed as omni directional antenna which however have low antenna gain and are easily detected. In the present invention the difficulties of the prior art are eliminated in that a separate antenna is provided for external or foreign protection and a separate antenna for self protection which antennas produced in the first plane a sharply focused pattern and in a plane perpendicular thereto a radiation pattern (7, 8) which is optimized for external or foreign protection or self protection, respectively.

Abstract: In a dual-band antenna of the beam wave-guide type, first and second electromagnetic waves from first and second feed horns, respectively, are directly provided to a frequency selective reflector along different axes, with both electromagnetic waves being provided from the frequency selective reflector along the same axis. The two electromagnetic waves are then reflected in common by first and second concave mirrors and then provided substantially along an axis coincident with the azimuth axis to the remainder of the beam wave-guide section which is itself rotatable about the azimuth axis.

Abstract: A beam waveguide feeder in which a feed horn, a pair of revolvable paraboloidal reflectors, and at least one plane reflector are arranged in the order stated so as to form a path for an electric wave, said pair of paraboloidal reflectors facing each other and being equal in focal distance and off-set angle, their zeniths and focuses being on an identical plane, is characterized in that said feed horn can be fixed in position while its equivalent feed horn, i.e., the image of said feed horn focused by the beam waveguide feeder, can be moved into an arbitrary location and turned in an arbitrary direction.

Abstract: A flat face annular grooved metal surface surrounds a circular waveguide opening coupled to a small dipole radiator which excites the circular waveguide in its fundamental propagating mode (TE.sub.11). The dipole is arranged to rotate about its axis by means of an extension of its inner conductor, which forms a simple probe in a section of rectangular waveguide situated behind the circular waveguide. A dielectric shaft is fastened to the inner conductor and is brought to the outside of the rectangular waveguide where it is connected to a small motor. The motor is arranged so that it may be actuated remotely by any of several circuits. The dipole may be before the corrugated plate with bent arms. A pair of dipoles may be arranged perpendicular to each other with two separate coaxial connector antenna feed outputs for direct attachment to coaxial-type low-noise amplifiers.

Abstract: A mirror antenna employing a continuous mirror without a hole. A feed horn nd an electromagnetic lens, located behind a rotatable twist reflector (the mirror), collimates a beam toward a polarized reflector located near the twist reflector and tilted to aim energy toward the twist reflector. Energy reflected back toward the polarized reflector from the twist reflector passes through the polarized reflector to free space.

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: An antenna system having a main reflector, a sub-reflector, and a plurality of horns for radiating different frequencies includes a beam waveguide system which cancels cross polarization otherwise inherent in the system. If the antenna system uses a non-rotationally-symmetric sub-reflector the cross polarization caused thereby is cancelled by the beam waveguide system having at least two focusing reflectors and selected parameters. Alternatively the beam waveguide system can be used with a rotationally symmetric and stationary sub-reflector by being positioned to reflect said beam on the axis of the main reflector. Either the horns or the focusing reflectors may be rotatably switched, the other group being stationary.

Abstract: A correction method for transverse defocussing of paraboloid oriented relative to the source initially aligned with the focus consists of securing said paraboloid to first platform, articulating said first platform through hinge means jointed to second platform, itself articulated through further hinge means jointed to a stationary part, and then orienting said hinge means to said focus, while providing moving means for said platforms, said moving means being servocontrolled responsive to pointing error detector thereby to hold permanently said focus close to the source.Provision is also made of a parabolic antenna comprising means for carrying out said method. The system is applied to radio and TV broadcast apparatus aboard satellites.

Abstract: Disclosed is a conically scanning antenna emitting a beam of radiation which is modulated in phase but not in amplitude. In certain embodiments the antenna comprises a source of radiation including a horn illuminating a reflector, the horn being either inclined to the reflector axis or juxtaposed with a prism imparting such inclination to its direction of maximum radiation. The inclined horn or the prism is rotated about the axis by drive means supplying a reference scanning signal to a processor.

Abstract: An antenna system has a parabolic reflector mounted so that it points generally downwards and a primary aerial is located at the focus of that reflector. Waves from the primary aerial are reflected back by the parabolic reflector to a reflector plate through an aperture in which the primary aerial projects. Scanning in both elevation and azimuth is effected by movement of the reflector plate.

Abstract: An antenna system of the Cassegrain type, used with a tracking radar and adapted to conically scan incoming waves reflected by outlying targets, comprises a paraboloidal main reflector and two hyperboloidal auxiliary reflectors confronting same. One of the auxiliary reflectors is semitransparent and coaxial as well as cofocal with the main reflector whereas the other is solid with an axis inclined to that of the main reflector about which it rotates while keeping its foci in the focal planes of the semitransparent reflector.

Abstract: A radio navigation antenna system suitable for use in an aircraft is disclosed. The fed element of the system is stationary, being at one end of a coaxial conductor which extends through a hollow shaft of a motor. Mounted around the hollow shaft is a ground plane disc capacitively coupled to the outer sleeve of the coaxial conductor, thereby avoiding the use of brushes in the system. A cylindrical dielectric antenna support is mounted on the ground plane disc around the fed element. A T-shaped reflector is formed by a conductive layer on the cylindrical surface of the antenna support.

Abstract: A feed system for a geodesic Luneberg lens antenna system is disclosed, in which sequential cyclical scanning of a plurality of feed sectors of the lens from one transmitter/receiver is achieved with a minimum of dead time between successive scans.

Abstract: Inverse Cassegrain antenna making it possible to use on the one hand the qualities of a conventional fine beam for look-out and tracking functions and making it possible on the other hand to have a widened beam either in the elevation plane or in the bearing plane. According to one embodiment, this antenna is provided with a mirror constituted by two reflector - polarizer elements joined to one another by a hinge which permits the articulation thereof, a remote control device regulating their relative orientation.

Abstract: A 360 degree fan beam scanning antenna which includes a transreflector created by a plurality of reflecting elements arranged on a surface of revolution formed about a generating axis and a feed antenna rotatable about the internal focal circle of the transreflector that provides an illumination beam for the transreflector which minimizes spillover and antenna pattern skewing.

Abstract: A microstrip antenna is disclosed having an etched metal radiator element including a polarizing patch consisting of a two dimensional removal of metallization from the central portion of the radiator element with one dimension of the polarization patch being greater than the other dimension e.g. an elongated rectangle and selectively oriented with respect to the input axis whereby, for example, circular polarization is achieved by means of orienting the polarization patch substantially 45.degree. with respect to the input axis.

Abstract: A mechanically scanned antenna system having a multiport rotary switch for sector scanning is disclosed. The switch includes a stationary subassembly and a rotating subassembly. The stationary subassembly contains the input ports and the rotating subassembly contains the multiple output ports associated with each input port. Each of the multiple output ports of the switch is sequentially activated through its designed active sector to produce the desired antenna scan pattern. The stationary subassembly includes a barrier member which is rotatable to selectively orient and maintain orientation of the active region of the antenna system at any position through 360.degree..

Abstract: Apparatus for generating elevation and azimuth reference signals for use in demodulating a tracking error signal to provide elevation and azimuth error components for use in adjusting the position of a tracking conical scan radar antenna, includes a template ring having a notched periphery and being attached to a rotatable nutator of the antenna such that its peripheral notches are in a predetermined angular phase relationship with a reference position on a feed horn attached on the nutator, during rotation of the feed horn with the nutator. The apparatus further includes an optical transducer and electronic circuitry coupled thereto for producing the reference signals from a signal generated by the transducer in response to rotation of the ring with the nutator. As the ring rotates with the nutator, its notched periphery makes or breaks a photon path between light beam generating and sensing elements of the transducer.

Abstract: Tactical radio navigation systems provide bearing information to an interrogating aircraft in response to pairs of interrogation pulses received at a beacon transponder, such systems also provide distance measuring and identification information. To provide the required bearing information, pulses radiated from a central antenna array are modulated at a 15 Hz frequency and by a 135 Hz frequency, by reflector elements rotating around a stationary central radiator. A counterpoise system associated with the central radiator and the reflector elements uptilts the carrier frequency and the 15 Hz modulation. To provide more uptilt to the radiated signal and further decrease the total energy radiated below the horizon, a double circuit shield counterpoise is provided in the lower part of a radome assembly enclosing the antenna system.

Abstract: An antenna assembly wherein the direction of a beam of radio frequency energy may be changed by combining the effects of a mechanically movable reflector and an electromagnetic lens is disclosed. In the preferred embodiment the antenna arrangement includes a corporate monopulse feed arranged to produce a linearly polarized divergent beam which is first reflected from a linearly polarized paraboloid to direct a convergent beam toward a mechanically rotatable polarization-twisting reflector. A selected portion of a spherical electromagnetic lens arrangement is illuminated by the still convergent beam from the latter reflector, such lens then determining the direction of the beam finally propagated in free space.

Abstract: An aperture antenna comprising at least one reflector, a primary radiator, and a plurality of movable beam-wave-guide reflectors arranged between the reflector and the primary radiator for directing electric waves from the primary radiator towards the reflector, in which at least one of the movable beam-waveguide reflectors is controlled to displace a feeding point to the reflector, and in which wavefront defocusing distortion of a radiated electric wave resulting from the displacement of the feeding point is corrected by moving at least one of the remaining movable waveguide reflectors.

Abstract: A directional microwave antenna system comprising a concave reflector fed by a wave guide and splash plate assembly. Two rectangular apertures in the wave guide at the focus of the reflector admit energy to and from the splash plate. Impedance matching tabs protrude into the rectangular apertures to match the antenna system. Rectangular tabs provide improved VSWR, high side-lobe reduction with the reflector on-axis. Circular tabs provide improved VSWR and good side-lobe reduction with the reflector on or off axis.

Abstract: An antenna apparatus comprising a primary radiator having an axially symmetric field pattern, and a main reflector and a subreflector coupled to the primary radiator through a beam wave-guide path. The antenna rotating axis is aligned with the axis of the primary radiator but a little deviated from the polar axis or the earth. At least one movable beam waveguide reflector or electromagnetic lens is provided in a radio wave path between the primary radiator and the subreflector. The antenna rotating axis is adapted to be rotatable only within a small angular range. The beam wave-guide reflector or electromagnetic lens is moved to thereby deflect the antenna beam.

Abstract: The present invention relates to a scanning system comprising a three elet reflecting antenna, wherein two of the reflecting elements synchronously counter rotate about axes other than their optical axes in order to generate a linear scan.

Abstract: According to the present invention, radar rays are reflected off a rotating econdary reflector which is both tilted with respect to and synchronously translated, in simple harmonic motion, in a direction transverse to the axis of rotation of the secondary reflector. The combined effect of the tilting and translating of the secondary reflector is to produce a line scan when the rays from the secondary reflector are reflected off a primary reflector.

Abstract: A feed which is stationary relative to a parabolic reflector is located in close proximity to a prime focus of the reflector along its central axis. A moving element which is opaque to r.f. energy is moved along a path of revolution about the reflector axis, the path of revolution being located between the reflector and the stationary feed. The shape of the opaque element and the path of revolution are such that different portions of the aperture of the feed are masked as the element travels along the path of revolution. This imparts predictable scanning motion to the beam pattern which is coupled into the stationary feed. One highly useful embodiment of this invention is a construction in which the stationary feed is a secondary feed installed in a nutating feed antenna, and the nutating feed itself constitutes the opaque moving element.

Abstract: An improved Lewis scanner comprising a focal lens having two best focus angles positioned with its axis at an angle other than perpendicular to the antenna aperture. The antenna aperture is maintained vertical with respect to the earth's surface to provide a planar beam at 0.degree. elevation. The focal lens axis is oriented at an angle of typically one-half the maximum elevation scan angle. The angle of the microwave reflector between the parallel plates of the Lewis scanner is changed from the conventional 45.degree. by one-half the angle between the focal lens axis and the 0.degree. elevation angle. An asymmetric feed lens improves the beam shape over the entire scan range.

Abstract: A plurality of steerable beam feed devices are used in combination with a single stationary toroidal antenna which permits simultaneous communication with several geosynchronous satellites. Each feed device is movably mounted on a flat elevation plate having linear bearings which mate with rails on a flat azimuth plate to allow the feed to be positioned vertically or at some angle with respect to the vertical depending upon the orientation of the antenna. The flat azimuth plate is mounted for movement on two curved rails which follow the focal arc of the toroidal antenna. Linear actuator devices are provided for moving each plate within a limited range to provide fine positioning of the feed relative to the antenna.

Abstract: In an antenna of the Cassegrainian or Gregorian type including a periscope arrangement, the auxiliary reflector has a longer focal distance than the auxiliary reflector of a conventional antenna of this type and the length of the optical path between the auxiliary reflector and the primary source of the antenna is choosen substantially equal to the distance between the auxiliary reflector and that one of its two foci which is the more remote therefrom. This makes it possible to use only plane mirrors in the periscope arrangement.