Showing papers on "Reflector (antenna) published in 1968"

Fields in the image space of symmetrical focusing reflectors.

Abstract: The fields scattered by circular symmetric reflector illuminated by a linearly polarised wave incident normally on the aperture are calculated from the induced surface currents. It is shown that the fields in the axial region can be represented by a spectrum of near-spherical hybrid waves propagating along the axis. For large microwave focusing reflectors, the wavefronts are effectively plane in the significant part of the image space. The axial wave fields are linear combinations of the TEln and TMln fields appropriate for circular metal pipes, but can be bounded only by anisotropic-reactance surfaces. Axial-wave theory is used to investigate the characteristics of the fields in the focal region of a paraboloidal reflector, when the incident wave is uniform and plane. For radiotelescope focal ratios, the image structure differs significantly from the classical Airy pattern, deduced by scalar analysis, of optical focusing systems. Energy vortexes circulating about the dark rings influence the efficiency obtainable from aperture-type feeds in the focal plane. Application of axial-wave analysis to spherical reflectors, and the synthesis of high-efficiency low-noise feeds, using hybrid-waves in corrugated guides, are described briefly.

The pointing calibration of the Haystack antenna

Abstract: We have applied techniques of optical astronomy to calibrate the pointing of a high-resolution pencil-beam antenna by using radiometric measurements of cosmic radio sources. The Haystack antenna, a 120-ft paraboloidal reflector on an azimuth-elevation mount, was calibrated at a frequency of 15.25 GHz. The beamwidth at this frequency is 36 millidegrees; the rms residual pointing error after calibration was 2.90 millidegrees in azimuth and 3.45 millidegrees in elevation. A total of 172 measurements of pointing error were made on eight sources, and these data were fitted by the method of least squares to determine seven instrumental parameters that take into account axis-alignment errors and gravitational effects on the antenna structure. These techniques are not restricted to antennas used as radio telescopes, and they may be useful in the pointing calibration of other antennas.

Self‐q‐switching in ruby lasers

Abstract: A laser consisting solely of a pumped ruby rod and rear reflector has been operated so as to produce single giant pulses.

Ultrasonic Examination of Liquid‐Solid Boundaries Using a Right‐Angle Reflector Technique

Abstract: A motor‐driven ultrasonic goniometer is described consisting of a single transducer and a 90° reflector. This relatively simple device facilitates rapid investigation and automatic recording of reflection data. The reflectivity curves are interpreted in terms of reflector geometry and the physical properties of the specimen. Among other things, the technique has been used to determine surface‐wave velocities in the Y‐Z plane of quartz, and the results are shown to be in reasonable agreement with both theoretical and other experimental data.

Antenna array at focal plane of reflector with coupling network for beam switching

Abstract: An antenna system for steering plural beams from a secondary reflector is formed from a primary array of linear feed elements, which can be arranged in either a one- or two-dimensional configuration. By controlling which of the radiators are simultaneously excited with a switching matrix, the position of the primary beam is varied as a function of the axis of the reflector forming the secondary beam.

Photoflash lamp array

Abstract: A multilamp photoflash array with lamp reflector units in linear rows facing in opposite directions with the reflectors of each row nested into the reflectors of the opposite row. Insulation means between rows of reflectors and convection cooling means minimize distortion of adjacent reflectors on flashing of lamps.

Optical solar reflector - A highly stable, low alpha sub S/epsilon spacecraft thermal control surface.

Abstract: Stable optical solar reflector for spacecraft thermal control, summarizing simulated exposures results

Communications systems utilizing a retrodirective antenna having controllable reflectivity characteristics

Abstract: A communications system is described which utilizes an antenna having means for selectively controlling the amount of incident electromagnetic energy directionally reflected therefrom. The antenna is comprised of a spherically configured array of conductors which focus incident energy on a reflector whose electrical conductivity characteristics and thus reflectivity characteristics can be controllably varied. The reflector can comprise a gas tube whose conductivity and thus reflectivity characteristics are a function of the number of ionized gas molecules therein. Modulation of the reflector reflectivity characteristics permits identification information, for example, to be impressed on the energy reflected therefrom.

Interference filter with dielectric tuning layers

Abstract: A THREE REFLECTOR INTERFERENCE FILTER IN WHICH THE TWO SPACER ELEMENTS USED TO SEPARATE THE REFLECTORS ARE MADE OF SOLID GLASS. THE TWO OUTER REFLECTORS ARE MULTILAYER DIELECTRIC FILMS AND ARE FORMED ON SEPARATE SUBSTRATES. THE OUTER ENDS OF THE TWO SPACER ELEMENTS ARE OPTICALLY CONTACTED TO THE SUBSTRATES. THE INNER ENDS OF THE SPACER ELE- MENTS ARE OPTICALLY CONTACTED TO EACH OTHER. THE INNER REFLECTOR, WHICH IS A METAL FILM IS FORMED ON THE INNER END OF ONE OF THE SPACERS.

Floodlight reflector-retaining means

Abstract: A cast metal floodlight body is provided with an arcuate cavity and integral internal reflector-mounting hooks. The reflector trough positioned within the cavity is a resilient sheet having slots adjacent parallel edges to receive the cast hooks. Securing screws retain the reflector trough in position and cooperate with the mounting hooks to shape it.

Variable interference reflector

Abstract: A REFLECTOR DEVICE CAPABLE OF PROVIDING A DESIRED VALUE OF REFLECTANCE AND HAVING A MULTI-LAYER REFLECTING SURFACE WHICH GRADUALLY DECREASES IN THICKNESS, FOR EXAMPLE EXPONENTIALY, FROM ONE END TO THE OTHER END SO THAT THE REFLECTANCE VALUE AT ANY POINT IS DEPENDENT ON THE POSITION OF THE POINT AND VARIES LOGARITHMICALLY ACROSS THE SURFACE. THE DEVICE IS PROVIDED WITH TWO CONTROLS, ONE BEING A REFLECTANCE ADJUSTMENT CONTROL AND THE OTHER A WAVELENGTH ADJUSTMENT CONTROL.

Street-lighting luminaire

Abstract: A street-lighting luminaire having an enclosed optical system adapted for containing a vertically burning mercury vapor lamp. The luminaire includes an overhead housing assembly separated by a dish-shaped reflector from a downwardly depending sealed optical assembly. A ballast assembly, socket mounting and positioning assembly and luminaire mounting bracket are located within the overhead housing assembly. The socket mounting and positioning assembly is mounted on the reflector within the overhead housing assembly and is constructed and arranged to provide for the horizontal and vertical adjustable repositioning of a lamp socket which is mounted on the lamp mounting and positioning assembly and which extends, through an aperture centrally located in the reflector, into the sealed optical assembly.

Vehicle headlamp with two light sources

Abstract: A main parabolic reflector has an iodine lamp located slightly in front of the reflector focal point. A masking element below the lamp defines a plane below which no light from the lamp strikes the reflector. An auxiliary reflector having an aperture substantially one half that of the main reflector has a second iodine lamp at its focal point. The vertical axis of the auxiliary reflector is spaced from the vertical axis of the main reflector, and the aperture of the auxiliary reflector is tangent to the plane defined by the mask.

Device for producing stimulated infrared emission, an iraser

Abstract: The invention provides for producing stimulated infrared emission, an iraser, by means of an electric discharge in a gas mixture partly consisting of carbon dioxide in which the discharge space is closed at one end by a concave metal mirror and at the other end by a coupling-out window which covers the whole cross section of the discharge space and also acts as a reflector, according to the invention, this window consists of a plate of zinc selenide which is coated on the discharge side with a few reflection-increasing layers and on the outer side with a reflection-decreasing material. The surface of the plate on the discharge side and the metal reflector at the other end of the discharge between the reflectors.

Improvements in and relating to reflectors

Abstract: 1,110,073. Reflectors for infra-red heaters. BRITISH IRON & STEEL RESEARCH ASSOCIATION. 18 Nov., 1966 [9 Nov., 1965], No. 47442/65. Heading H5H. [Also in Division F4] A reflector comprising main energy-reflecting surfaces A, shaped parabolically, with a recess having a further reflecting surface C, also shaped parabolically, joined to said surfaces A by intermediate curved surfaces B which in the plane at right angles to the heating element (shown dotted) define arcs of a circle, provides parallel beams of energy when the element is assembled in the reflector at the common focus of said curves A, B and C. Alternatively, curves A and C may be elliptical in shape.

Ultrasonic apparatus for measuring the position of a liquid level

Abstract: 1,123,939. Ultrasonic measurement of liquid level. COMMISSARIAT A L'ENERGIE ATOMIQUE. 13 Dec., 1966 [15 Dec., 1965], No. 55822/66. Heading H4D. In an ultrasonic liquidlevel gauge, ultrasonic waves are conducted through a guide vowprising a tube filledhithan auxiliary liquid moaing acoustic properties similar to those of the liquid whose level is to be gauged. For measuring the level 17 of liquid sodium or sodium - po - tassium coolant 51 in a nuclear reactor vessel the tube 1, containing a eutectic sodiumpotassium mixture, is adjustably mounted in the vessel wall by means of flanges 15, 16, screws 19 and metal bellows 18. The tube 1 is sealed by acoustically transparent end-plates 3, 4, and is surrounded by perforated tube 28 which dampens movements of the coolant surface 17 and also supports a conical reflector 22. Ultrasonic pulses generated by a quartz transducer 6 (adjustably mounted in a kerosene-filled casing 5) pass through the waveguide, are reflected from reflector 22, and pass between tubes 1 and 28 to the coolant surface 17 from which they are reflected back via the same path to the or a further transducer. The echo-time of a pulse provides a measure of the coolant level. Lugs 31 at known positions in tube 28 provide reference echoes for calibration purposes. In alternative embodiments the gauge is mounted in or near the bottom of the reactor vessel (Figs. 3 and 4, not shown), whereby the ultrasonic pulses can be directed through the waveguide to the coolant surface without the need for the conical reflector 22, or is mounted in the vessel side wall (Fig. 5, not shown) with the waveguide horizontal, a plane reflector being used to direct the pulses upwards to the coolant surface.

Photoflash lamp array with reflector-lamp module

Abstract: A photoflash lamp-reflector module for use in a photoflash array for providing optimum optics in a minimum of space where the light source is comparatively large relative to the reflector surface. The module consists of a reflector with a parabolic-type surface for essentially its entire effective reflecting area and a tubular photoflash lamp positioned in the innermost part of the reflector transversely of the axis thereof with the reflector essentially tangent to the lamp. The reflector has an angle relative to its optical axis in the direction of light projection of approximately 45* at a point on that portion of the reflector which is adjacent the centerline of the lamp and extends forwardly of the lamp axis.

Sectional parabolic reflector

Abstract: 1,196,857. Aerials. H. A. PAYNE. 22 July, 1968, No. 34953/68. Heading H4A. A paraboloidal reflector comprises a central sheet member 12, Fig. 2, and an annular sheet member 14. The members are separate, but are provided with means at their abutting edges to maintain their respective reflecting surfaces in paraboloidal relationship. As described, rearwardly directed flanges 16, 18 which are formed on the members 12, 14 are bolted together, with a metal ring 20 intermediate. The said ring supports the reflector as a whole, and can be mounted on a tower or the like. The annular sheet member 14 may be divided radially into a plurality of sub-members 14a which may be joined together by welding or by bolting to mouldings 17, Fig. 3.

Rotable arcuate reflector system for telescopes

Abstract: A REFLECTOR SYSTEM HAVING PARTICULARLY ADVANTAGEOUS APPLICATION TO LINE-OF-SIGHT POINTING AND TRACKING TELESCOPES AND CHARACTERIZED BY A PRIMARY SYSTEM INCLUDING AN ARCUATE, STRIPLIKE SEGMENT OF A DISHED, REFLECTING SURFACE MOUNTED FOR AZIMUTH ROTATION AND A SECONDARY SYSTEM SUPPORTED FOR ELEVATIONAL ROTATION ABOUT AN AXIS FIXED RELATIVE TO THE SURFACE OF THE SEGMENT AT A POINT SUCH THAT THE SECONDARY SYSTEM IS CAUSED TO DESCRIBE AN ARC INTERSECTING POINTS ADJACENT TO THE FOCI OF THE PRIMARY SYSTEM, WHEREBY THE SURFACE OF THE SEGMENT SERVES AS A PRIMARY LIGHT-GATHERING SURFACE FOR AN OPTICAL TELESCOPE AS THE TELESCOPE IS EMPLOYED TO TRAIN AND TRACK A MOVING POINT-SOURCE OF LIGHT THROUGHOUT THE CELESTIAL HEMISPHERE

Improvements in or relating to visual indication of temperature change

Abstract: 1103705 Temperature indicators MUIRHEAD & CO Ltd 18 Jan 1967 [25 March 1966] 13263/66 Heading G1D [Also in Division G2] A glass or like reflector for mounting in a position exposed to ambient temperature contains a solution undergoing a colour change over a particular temperature range eg at or near the freezing point of water, whereby when a light beam falls on the reflector a marked colour change is observed in the reflected beam when the temperature passes the particular temperature range The solution may be iodine in carbon tetrachloride or alcohol and the reflector may be mounted on a post at the roadside to give an indication to passing vehicles that the temperature was approaching freezing point Alternatively, the reflector may be incorporated in a lane marker reflecting unit in a roadway

Optical scanning apparatus utilizing a re-entrant laser beam

Abstract: In the synchronous scanning display device disclosed, the laser active medium and means for mode-locking multiple-mode laser oscillations are disposed in a resonator adapted to provide a folded optical path yielding a large plurality of resolvable spots at a reflector of stepped transmissity and reflectivity. The intensity of the output from the resonator at each spot is selectively controlled by a video signal applied to a broad area modulator disposed just outside the stepped-reflectivity reflector. Typically, an isolator is employed to produce unidirectional propagation of the laser radiation along the folded path.

Portable parabolic reflector for microwave energy

Abstract: A PORTABLE PARABOLIC MICROWAVE REFLECTOR GENERALLY IN THE FORM OF A CROSS COMPRISES A SERIES OF MALE AND FEMALE ALUMINUM CASTINGS JOINED TOGETHER BY MEANS INCLUDING AN ALIGNMENT PIN AND SPRING-LOADED BALLS. ASSEMBLED REFLECTOR SECTIONS ARE SUPPORTED BY WELDED, TUBULAR A-FRAMES THAT BECOME ATTACHED TO THE REFLECTOR BY MEANS OF A SERIES OF MALE AND FEMALE ALUMINUM CASTINGS IN CONJUNCTION WITH AN ALIGNMENT PIN, LOCKED IN PLACE BY SPRING-LOADED BALLS. THE A-FRAMES ATTACHED TO WHATEVER SUPPORT STRUCTURE IS REQUIRED TO SUPPORT THE ANTENNA.

Improvements in and relating to light fittings

Abstract: 1,102,270. Electric lighting fittings. FALKS Ltd. 19 Jan., 1967 [18 Aug., 1966], No. 37093/66. Heading F4R. A fitting, especially for fluorescent discharge lamps, includes an elongated parabolic reflector 12 having transverse wedge-shaped louvres 56 point downwards. The reflector is supported by a casing 10 in which is the control gear 35 for the lamp, by means of permanent magnets 32 on the casing which co-operate with keepers 42 on the reflector. The casing has a channel element 18 surrounding the opening into which a flange on the reflector fits. The top of the reflector is cut away to allow for the passage of the discharge tube, a reflector corresponding to the cutaway portion of the reflector 12 being mounted above the tube. The fitting is supported in the ceiling by arms 67 mounted on adjusting screws inside the casing.

Improvements in or relating to aerial systems

Abstract: 1,133,343. Aerials. NATIONAL RESEARCH DEVELOPMENT CORP. 12 Sept., 1966 [17 Sept., 1965], No. 39747/65. Heading H4A. In an aerial system an open-ended waveguide 1 is axially displaced by a distance h from a plane or slightly curved reflector which comprises a layer 3 of low-loss dielectric material backed by a layer 5 of radio absorbing material 5, such as rubber loaded with graphite. The reflector may be mounted on a metallic skin 4, which may be part of an aircraft fuselage. The waveguide aperture is arranged to emit circularly polarized radiation and the thickness and dielectric constant of the layer 3 are selected to obtain reinforcement of the direct and reflected waves in desired directions corresponding to angles of incidence of the latter exceeding the Brewster angle. Instead of the apertured waveguide 1, crossed dipoles suitably energized or a helical aerial may be used, and the radiator axis may diverge from the reflector. Auxiliary reflectors of similar construction to the main reflector may be arranged in step formation between it and the radiator, to fill in residual minima in the radiation pattern (Fig. 2, not shown). In one alternative arrangement, Fig. 3, a biconical horn 10 is fed by slots 11 to produce circularly polarized radiation in an omnidirectional pattern. It is located with its axis perpendicular to a main reflector 12, with annular auxiliary reflectors 13, 14 interposed.