Abstract: A termination for a VHF inverted-V half-rhombic antenna is described, consisting of a transformer terminated into a length of high attenuation coaxial cable acting as a power dissipation line.

Abstract: A thin layer of a non-stick coating having a low coefficient of friction and a low solar reflectivity producing a non-wettable surface is applied to the reflecting face of an inclined dish receiving antenna to prevent the build-up of ice or snow on the reflecting face of the antenna.

Abstract: A cross polarized wire grid antenna is disclosed which produces circularly polarized electromagnetic radiation. A subarray layer of the present invention comprises a plurality of interconnected rectangular elements. The elements are connected and fed so that the short sides of the rectangles serve essentially as radiating elements, and the long sides of the rectangles serve essentially as nonradiating transmission line elements. In an embodiment of the present invention, a first subarray comprises two layers of horizontally polarized radiators and a second subarray comprises two layers of vertically polarized radiators. The two subarrays are combined to form a cross-polarized antenna array which produces circularly polarized electromagnetic radiation. The layers of each subarray are electrically isolated from one another and are displaced 1/2.lambda. with respect to each other perpendicular to the direction of polarization of the subarray.

Abstract: The present invention relates to a multibeam antenna arrangement comprising a main focusing reflector, a doubly curved subreflector disposed confocally with the main reflector and a plurality of feeds disposed on a doubly curved focal surface of the antenna on which an image of the far field of view is formed. The subreflector is doubly curved in orthogonal directions to introduce a predetermined amount of barrel distortion for transforming a three-dimensional, non-rectangular, matrix in the far field of the antenna arrangement into a substantially rectangular matrix on the doubly curved focal surface of the antenna arrangement. Feeds are aimed such that a central ray from each feed reflected by the subreflector impinges a common point on the main reflector.

Abstract: An antenna luggage rack for a vehicle having a substantially rectangular, rigid ringlike frame which has stanchions secured to the corners thereof for fixedly positioning and supporting the frame in upwardly spaced relationship from the roof of a vehicle. The frame defines therein an upwardly opening luggage-receiving pocket. The frame is defined by opposed parallel side rails joined together by front and rear cross rails which extend perpendicularly therebetween. Brackets are secured to opposite ends of the cross rails for securing the latter to the side rails. The brackets at one diametrically opposite pair of corners of the frame are of an insulative material, whereas the brackets at the other pair of diametrically opposite corners of the frame are of a conductive material. One side rail and connected cross rail hence define one elongated conductive path, and the other side rail and connected cross rail define another elongated path of substantially the same length.

Abstract: The present invention relates to an antenna feed arrangement capable of providing a zero reflection response at a first frequency of interest and a maximally flat response at a widely separated second frequency of interest. The feed arrangement comprises a smooth-walled waveguide section at a first end, a corrugated waveguide section at a second end designed to provide the zero response at the first frequency, and a quarter-wave transformer waveguide section disposed between the smooth-walled and corrugated waveguide sections designed to provide the maximally flat response at the second frequency. The quarter-wave transformer section comprises a plurality of N corrugated waveguide subsections, where N.gtoreq.2, which comprise corrugation depths corresponding to the corrugation depths in the corrugated waveguide section.

Abstract: An amplitude control circuit and variable phase shifter driver, employable in electronically steerable antennas, compares amplitude and phase command signals for the amplitude controller and phase shifter with command signals derived from the amplitude ratio and phase difference between a reference r.f. signal and an r.f. signal at a selected location. The difference signals resulting from this comparison are added to the amplitude and phase shift command signals and applied to the amplitude controller phase shifter drivers to adjust the amplitude controller and phase shifter.

Abstract: A multiple-feed Luneberg lens scanning antenna system. A Luneberg lens disposed for rotation. A first antenna feed is connected to and defines a first feed point on the surface of the lens. A plurality of second antenna feeds are respectively connected to and define a plurality of second feed points outside and closely adjacent the periphery of the lens. Supporting structure separately supports each of the second feeds at positions independent of the rotation of the lens. A drive system is coupled to the supporting structure for separately positioning each of the second feeds. The drive system also is coupled to the lens for rotating the lens to cause the first feed point to scan over a wide angle.

Abstract: A microwave antenna is made of a pair of parallel ground-plane conductors (12 and 14), one of which forms a generally cruciform aperture (18). A pair of T-shaped feedlines are disposed with their cross pieces (22 and 34) in registration with the respective arms (20 and 36) of the aperture 18 and are independently driven from stems (26 and 32) disposed between the ground-plane conductors.

Abstract: A radio frequency antenna comprising a rectangular waveguide having opposing relatively concave-shaped narrow side wall portions extending from a rear wall of the waveguide structure to an aperture of the antenna element. The separation between the sidewalls, at a distance intermediate the rear wall and the aperture, is greater than the width of the aperture. The waveguide includes a ridge-shaped feed structure extending from the rear wall to the aperture. A pair of ground plane conductors having surfaces each with an edge terminating along an aperture edge of a corresponding one of the sidewalls at the periphery provide a pair of aperture edges. Each one of the ground plane conductors extends for a length greater than .lambda./3 where .lambda. is the wavelength at the lowest operating frequency of the antenna. With such arrangement, an antenna element is provided having a relatively constant beam width over the operating bandwidth of the antenna.

Abstract: A microstrip antenna is disclosed consisting of a flat metallic patch spaced from the ground plane. To increase the bandwidth of the antenna a pair of varactor diodes are provided positioned at opposite sides of the patch and connected between it and the ground plane.

Abstract: The arrangement is for cancelling unwanted sidelobes in travelling-wave arrays, especially the back lobe where the main beam approaches the end-fire direction; the array should have high symmetry, i.e., with the usual form of array (radiators spaced along a single feeder), the radiation patterns when fed from either end should be mirror images. Cancellation is obtained by having feed connections (2,2') at both ends of this form of array (1), the feed at one end being attenuated (8) relative to the other and effectively subtracted (6) therefrom. In RF form, for receiving or transmitting, the subtraction can be effected by phase-reversing (7) the signal in one of the feed connections. In baseband form, suitable for receiving only, diodes are included in both feed connections and subtraction performed at baseband frequency.

Abstract: A system for connection by means of optical fibers for the bidirectional exchange of data between a fixed central unit and peripheral units integral with a frame driven with a rotary movement, this system comprising radiating energy emitting and receiving means situated in the fixed part, coupled by optical fibers forming unidirectional data exchange paths to a single mixing fiber, itself coupled to optical fibers forming bidirectional data exchange paths coupled to radiating energy emitting and detecting means associated with the peripheral units integral with the mobile frame. Furthermore, the mixing fiber is split into two parts coupled together by a rotary optical joint.

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: Microwave radiation source operating in two different frequency bands comprising two open cavities energized by two orthogonal dipoles, situated one within the other, the two cavities being wholly reflective for the waves transmitted by their corresponding energizing dipoles, and the interior cavity being transparent for the wave transmitted by the dipole energizing the exterior cavity.

Abstract: Earth station antenna and method for assembly wherein the antenna has a frame made up of accurately stamped radial ribs and circularly disposed cross members, the frame being filled in by either sheet metal segments or by screen mesh segments to form a parabolic surface. The ribs are supported by a central ring or barrel, which is rotatable during assembly, and by back braces which are adjustable to bring the ribs to true parabolic positions and to tune the completed antenna. Assembly may be done from the ground by rotation of the central barrel. Novel connection means and a positioning gage are used during assembly of the antenna.

Abstract: An antenna arrangement consists of a dipole radiator which is fed via a Triplate three-layer transmission line. The dipole is arranged to radiate and receive plane polarized electro-magnetic radiation having a plane of polarization which is determined by the orientation of an elongate slot in the dipole radiator. The Triplate is coupled to the dipole so as to maintain a substantially constant impedance over a reasonably wide bandwidth. A large number of similar dipole radiators can be mounted side by side and fed from a common Triplate structure and in this latter case a common reflector is used for all dipoles and is mounted on the Triplate structure itself.

Abstract: A microstrip cylindrical antenna comprised of two concentric subelements on a ground cylinder, a vertically polarized (E-field parallel to the axis of the antenna cylinder) subelement on the inside and a horizontally polarized (E-field perpendicular to the axis) subelement on the outside. The vertical subelement is a "wraparound" microstrip radiator. A Y-shaped microstrip patch configuration is used for the horizontally polarized radiator that is wrapped 1.5 times to provide radiating edges on opposite sides of the cylindrical antenna for improved azimuthal pattern uniformity. When these subelements are so fed that their far fields are equal in amplitude and phased 90.degree. from each other, a circularly polarized EM wave results. By stacking a plurality of like antenna elements on the ground cylinder, a linear phased array antenna is provided that can be beam steered to the desired elevation angle.

Abstract: An antenna for circularly polarized high-frequency signals comprising a succession of layers. An insulating layer 10 includes openings defined by metal plated walls forming miniature horns, each having a square cross-section. A dielectric layer 19 adjacent layer 10 supports a first supply network 20 for signals whose direction of polarization is of a first type of linear polarization. An insulating layer 30 adjacent layer 19 includes openings defined by metal plated walls forming miniature waveguides each having the same square cross-section as a respective horn, at the side facing the first network 20, and having a rectangular cross-section at the other side. A dielectric layer 39 adjacent layer 30 supports a second supply network 40 for signals whose direction of polarization is perpendicular to the polarization of the signals of the first network.

Abstract: A multiband aerial, especially suitable for a motor vehicle window, or for application to the window, which comprises a single conductor wire which starts from a signal pickup position, terminating in just the one free end, and which includes the FM aerial section and the AM aerial section, with such sections being connected in series, and therefore not requiring phasing, and being electrically isolated by means of an inductor, preferably of box rib pattern, which inductor can function as an open circuit in the FM band and as a short circuit in the AM band. The series of vertical and horizontal segments, forming the sole aerial conductor wire which contains in series such FM section and AM section, can be of variable, but always asymmetrical, geometry or configuration.