Showing papers on "Reflector (antenna) published in 1975"

Deployable reflector structure

Abstract: A supporting structure that deployed resembles a spoked wheel which is retractable into a compact volume by virtue of hinged rim and reelable spokes that is an efficient and stable structure for storing, deploying and supporting surfaces such as radar and communications antennas, shielding, earth sensing, solar cell arrays and solar energy reflectors.

Solar energy heating system

Abstract: A focused solar heating system is provided having a focusing reflector which is generally scoop-shaped. A solar collector plate is mounted on the front of the focusing reflector to directly accept direct solar radiation and diffuse radiation which strikes the front surface of the plate. The remainder of the entrance aperture of the focusing reflector accepts both onand off-axis solar direct and diffuse radiation which is reflected by the focusing reflector and applied to the rear surface of the solar collector plate. The focusing reflector has a concave reflective surface made up of first and second merging curves which are optimized so that the front and rear surfaces of the solar collector plate accept the larger solid angle of both direct and diffuse rays from the sun and provides an optical gain which increases the efficiency of the system. The solar collection system may be incorporated in a vertical wall of a building and made partially transmissive, or may be incorporated in a separate structure for supplementing the heating or cooling of a building or providing hot water therefor.

Spurious signals generated by electron tunneling on large reflector antennas

Abstract: Large reflector antennas are currently fabricated by assembling a large number of small light aluminum panels onto a superstructure. A large number of aluminum-to-aluminum joints are inherently exposed to RF radiation on such an antenna. It is shown in this paper that the natural oxide layer on aluminum is of the correct thickness to permit electron tunneling through the Al-Al 2 O 3 -Al junctions. The nonlinearity due to the junctions then generates spurious signals when these antennas are used for simultaneous transmission and reception of signals at different frequencies. Moreover, the large number of junctions (rivets) on an antenna can combine to produce serious inteference in these diplexed systems.

Radiant zone heating apparatus and method

Abstract: A heating zone of accurately controlled length and predetermined energy profile throughout its length is formed within a focusing apparatus. An elliptical cavity is provided having a conically-configured reflector positioned such that its longitudinal axis coincides with one of the focal axes of the elliptical cavity. An elongate body is placed within the cavity such that its longitudinal axis coincides with the other focal axis. When a beam of radiant energy within a wavelength range which couples with the body to heat it, e.g., a laser beam, is directed onto the conically-configured reflector it is concentrated uniformly around the body throughout a predetermined length. The energy profile along the zone length may be varied either by adjusting the energy distribution in the energy beam prior to being reflected, by modifying the surface contour of the reflector, by modifying the contour of the walls defining the elliptical cavity or by a combination of two or more of these techniques. A plurality of overlapping elliptical cavities may be arranged to have one common axes along which the reflector is positioned and a plurality of axes along which a plurality of elongate bodies are positioned. The apparatus of this invention is particularly suited for heating rods and tubes and, if desired, for use within a controlled atmosphere.

Solar energy collecting system

Abstract: A solar energy collecting system, which may be operated to provide usable energy throughout the year, comprises a plurality of rows of elongate radiant solar energy collecting panels, each having upper and lower edges, being mounted to form an angle to the horizon and to face the sun's position at solar noon. An elongate reflector, also having upper and lower edges, compliments each row of collector panels to reflect radiant solar energy to it. The upper edge of each row of collector panels is positioned adjacent the upper edge of a reflector to define a single, inverted, generally V-shaped peak. The lower edge of each collector which forms a part of one peak is spaced from the lower edge of the reflector which forms a part of an adjacent peak to define a valley. A walkway is constructed in each valley to provide access to both the reflectors and collector panels for drainage and maintenance. To achieve optimum year-long system operation, the height of the peaks as well as the horizontal distance beween them is such that little or no shadow falls on the collector panels near noon on the winter solstice. Further, a plane tangent to each reflector at its upper edge makes an angle with the horizon less than one-half the solar altitude during the season when maximum system performance is desired to insure that most reflected solar radiation is incident on the collector during this season.

Solar heating device

Abstract: Solar heating device utilizing a cylindrical reflector with a spirally extending a section and a parabolically extending section for concentrating solar energy on an axially disposed absorber carrying a fluid to be heated. Substantially all of the energy impinging upon the reflector is reflected inwardly and ultimately strikes the absorber. The curvature of the reflector is such that the device can be mounted in a fixed position and deliver a large amount of concentrated solar energy to the absorber throughout the year. In some embodiments the reflector has an additional spirally extending section adjacent to the first spiral section, and embodiments having a plurality of reflectors and absorbers are also disclosed.

Faceted parabolic-type reflector system

Abstract: A luminaire including a segmented and faceted reflector of two sections describing a concave surface but approximately describing a plurality of paraboloid surfaces of revolution. With simple repositioning of the two reflector sections, a range of reflected beam widths may be achieved. The construction of the reflector sections provides economic fabrication without material reshaping or working and hence dulling of highly reflective material, the fabrication steps including V-notching and bending in two directions.

The geometrical theory of diffraction for axially symmetric reflectors

Abstract: The geometrical theory of diffraction (GTD) (cf. [1], for example) may be applied advantageously to many axially symmetric reflector antenna geometries. The material in this communication presents analytical, computational, and experimental results for commonly encountered reflector geometries, both to illustrate the general principles and to present a compact summary of generally applicable formulas.

Reflector synthesis for generalized far-fields

Abstract: The theoretical foundations of a proposed new method of reflector design are presented The geometric-optics approximation is used to synthesise a reflector surface to produce a generalized far-field when illuminated by a point source The far-field can have a prescribed variation in two variables and source blockage can be removed The technique of differential geometry are used to show that a nonlinear second-order partial differential equation, the Monge-Ampere equation, must be solved subject to nonlinear boundary conditions Particular consideration is given to the special case of fields with even azimuthal symmetry when referred to spherical polar coordinates The method is applicable to problems in optics acoustics and microwave antenna design where shaped beams are required

Attachment for reflectors for spoke wheels

Abstract: An attachment for combination with wheel reflectors attached to and/or carried by the spokes of spoke wheels. Wheel reflectors normally provide increased visibility from only right angles to the direction of travel. The attachment, of double-faced reflectorized construction in its preferred embodiment, is carried by the wheel reflector at substantially right angles thereto and is of a size to pass between the wheel supporting frame members to which the wheel is attached. Being disposed normal to the wheel reflector, the attachment increases visibility in directions more or less parallel to the direction of travel and in use moves up and down with rotation of the wheel thereby providing the maximum degree of visibility from both forwardly and rearwardly directions-directions from which side reflectors are totally invisible.

Stationary concentrating reflector cum tracking absorber solar energy collector: optical design characteristics.

Abstract: This article presents an analysis of the optical design characteristics of a stationary reflecting/tracking absorber solar energy collector. This type of collector consists of a segment of a spherical mirror placed in a stationary position facing the sun, but having a linear absorber that can track the image of the sun by a simple pivoting motion about the center of curvature of the reflector. The optical characteristics of this system and the axial variation of its concentration ratio are developed to provide information for the engineering design and sizing of this type of solar energy collector system.

Erbium laser ceilometer

Abstract: A laser rangefinder for clouds, fog, haze and precipitation including an erbium doped laser transmitter, a germanium photodiode monitor and a germanium avalanche photodiode detector. The germanium avalanche photodiode and an amplifier module is positioned at the focus of a parabolic reflector. The transmitter transmits light in a waveband with an optical center at 1.54 microns and is eye safe. A periscope system aligns the outgoing pulse with the returning light to reduce parallax. To reduce alignment problems when shifts in wavelengths occur, an optical circuit with only reflecting surfaces can be employed. To increase the efficiency of the laser transmitter, the clamps utilized to position the laser rod within the cavity are formed of the same material as the laser rod and the pump light reflector is a second surface mirror with a quartz substrate coated in succession with silver, copper and black paint.

Double pass linear accelerator operating in a standing wave mode

Abstract: A double pass linear accelerator which is used in a radiation therapy unit to provide electron radiation or photon bremsstrahlung radiation when combined with an appropriate target. The accelerator operates in a standing wave mode and includes an accelerating section, a charged particle source and injection section, a microwave source operating in the S band and adapted to excite the accelerating section and a reflector system which is mounted at one end of the accelerating section to reflect a particle beam which has been accelerated due to one pass, back into the accelerating section such that it may be further accelerated. The distance between the reflector is made adjustable to provide for output particle energy variation.

Highly-directional acoustic source for use in borehole surveys

Abstract: A highly directional acoustic source for use in a well logging system wherein a fluid-filled tube is provided with a transducer at one end and an acoustic reflector at the other end to reflect the acoustic beam into the formation. The transducer is excited at two frequencies whose difference is the desired frequency and the tube is made sufficiently long to produce parametric generation of the difference frequency.

Optical encoder of the reflective type

Abstract: Reflective optical encoder for monitoring the movement of a machine tool component or the like. The encoder comprises a code disc having a code track thereon in the form of alternating radiation transmissive and radiation opaque areas. A source of radiation and at least two detectors are supported on one side of the code disc while a reflector is supported on the opposite side. Radiation from the source is directed through the code track to the reflector and is reflected off of the reflector back through the code track to the detectors such that the detectors will receive radiation modulated by the code track as a function of the movement of the code disc. The reflector is preferably provided with an aspheric reflector surface, and most preferably, with a conical reflector surface which can be adjusted in orientation to enable radiation directed to one of the detectors to be retarded in phase by desired amounts relative to radiation directed to the other detector to permit maximizing of the system resolution and to determine direction of rotation. The encoder system provided eliminates the need for the slit plate of conventional encoders and, in general, provides a low cost, medium resolution encoder having a minimum number of parts and reduced tolerance requirements.

Shaped-beam horn-reflector antennas

Abstract: A design method for a horn-reflector antenna, which has a beam of arbitrary cross section, is developed. To show the effectiveness of the design theory, the measured data of an electrical model of Japan's domestic communications satellite antenna of this type are shown in comparison with calculated results. The design theory is based on geometrical optics, and is applicable not only to a horn-reflector antenna, but also to any reflector antenna. At the first step of the design theory, the shape of the wavefront near the aperture is determined to correspond to desired beam shape. The shape of the reflector is then determined by the law of the optical path.

Two-mode RF phase shifter particularly for phase scanner array

Abstract: A space-fed phased-array arrangement in which the plural antenna elements each include first and second (front and rear) individual radiators. Between these input and output radiators, there is a combined controllable phase shifter and controllable electronic switching arrangement. In accordance with external control signals, the amount of phase shift (phase delay) introduced by each element may be controlled, and by appropriate programming of these phase shifts, beam formation and pointing angle may be determined. The electronic switch devices are programmable to convert any or all of the antenna elements to reflector or retro-directing elements whereby a rear-pointing beam may be generated and scanned in substantially the same way as the forward beam is generated and scanned. In the retro-directive (reflective) mode, energy from the primary feed passes bi-directionally through the reciprocal controllable phase shifter sections.

Low cost solar energy collection system

Abstract: A fixed, linear, ground-based primary reflector having an extended curved-sawtooth contoured surface covered with a metallized polymeric reflecting material, reflects solar energy to a movably supported collector that is kept at the concentrated line focus of the reflector primary. The primary reflector may be constructed by a process utilizing well-known freeway paving machinery. The solar energy absorber is preferably a fluid-transporting pipe. Efficient utilization leading to high temperatures from the reflected solar energy is obtained by cylindrical shaped secondary reflectors that direct off-angle energy to the absorber pipe. To obtain higher temperature levels, refocusing secondary reflectors, that cause a series of discrete spots of highly concentrated solar energy to fall on the fluid-transporting pipe, are utilized. A seriatim arrangement of cylindrical secondary reflector stages and spot-forming reflector stages produces a high temperature solar energy collection system of greater efficiency.

Loaded quad antenna

Abstract: A driven quad antenna unit includes four perpendicularly arranged antenna elements, each element containing therein a high Q load coil in order to reduce the overall size of the antenna structure. A similarly configured parasitic loop unit functioning as a director or reflector (or both may be employed) is located in front or behind, as the case may be, the driven antenna unit. As with the driven unit, each side of the parasitic unit has a coil connected therein, the number of turns in each coil of the director being somewhat less than in the number in the coils of the driven unit and somewhat greater in the coils of the reflector.

Reprographic fluorescent lamp having improved reflector layer

Abstract: An improved reflector layer is provided utilizing a titanium dioxide (TiO2) admixture containing up to approximately 15 percent by weight magnesia (MgO). Said reflector layer underlies the phosphor layer, and an aluminum oxide (Al2 O3) layer can be deposited upon the phosphor layer.

Bicycle distance safety device

Abstract: A bicycle safety device indicates not only the presence of a bicycle but the minimum distance that should be maintained by other vehicles in passing the bicycle. The safety device includes a support member that mounts to the bicycle frame immediately below the bicycle seat on the seat elevation-adjustment-bolt and extends parallel with the side of the bicycle frame and forms a right angle at the end. The parallel member includes reflector means on both of it's sides and an indicating member attached to said parallel support member and extends outwardly horizontal from the side of the bicycle frame a predetermined distance. Said horizontal member may be shaped into two or more arrows to create an illusion of a moving arrow and may be built out of reflector-type sheet metal, and will protect the bicyclist from all four directions, namely, north, south, east and west, because both of said members comprise reflector means on both of the sides.

Unit for treatment of substrate with ultraviolet radiation

Abstract: A system, designed to cure an ultraviolet sensitive coating on a substrate that is moving in a direction transverse to the radiation emitted from the system, which includes a plurality of arrays of short-arc ultraviolet lamps, each array located in a suitable housing. The arc of each lamp in a given array is located at the focus of an associated paraboloidal reflector mounted within the housing so that at least half of the ultraviolet radiation emanating from the arc is reflected by the paraboloidal reflector to produce a collimated beam of ultraviolet radiation directed toward a concave spherical reflector whose center is located axially with the paraboloidal reflector. As measured between the two reflectors, the axis of the spherical reflector normally forms a (45°) angle with respect to the axis of the paraboloidal reflector to reflect the collimated beam toward the substrate. Because of the concave surface of the spherical reflector, the radiant energy is focused to a small area on the substrate. This area is adjustable over a wide range depending on the focal lengths of the spherical and paraboloidal reflectors which are chosen so as to arrive at the most desirable intensity of radiation for the particular sensitivity of the coating being treated. Each array produces a set of disconnected high intensity image areas on the substrate, with the totality of arrays providing complete coverage across the width of the substrate. Within each array, the spherical reflectors are mounted to an assembly within the housing for pivotal movement into a position to reflect the focused beam 180° from its normal direction so that no energy strikes the substrate when it is not in motion.

Dust collection and illumination system

Abstract: An improved dust collection and illumination system is utilized in association with a plurality of work areas at which dust particles are formed during work operations. A combination lamp and dust collector is mounted on a workbench at each of the work areas and is connected with an exhaust manifold which conducts a flow of air and dust particles from the work areas to the intake of a blower. Each combination lamp and dust collector includes a reflector which is connected with the manifold by a flexible conduit and a light bulb which is mounted in the reflector and is effective to illuminate a work surface. Air and dust particles are drawn into the reflector, around the light bulb to cool the bulb, and through the flexible conduit and manifold to the blower. A linkage is utilized to support the reflector above the work surface. This linkage is adjustable to enable the position of the reflector to be changed.

Ultraviolet emitting fluorescent lamp having internal reflector film

Abstract: An ultraviolet emitting fluorescent lamp contains an internal reflector film to increase the forward flux of the lamp. The reflector film comprises a layer of zirconia on the inside glass wall of the lamp envelope.

Optical seeker scanning system

Abstract: A lens system directs an incident ray bundle to imaging means that is arranged about a system optical axis. The ray bundle is first intercepted by dihedral reflector means which rotates the ray bundle at an angular rate twice its own and a trihedral reflector means that intercepts the rotated ray bundle and proceeds to invert and revert that ray bundle. Dichroic filters are associated with each of the dihedral or trihedral reflector means and are effective to disassociate the ray bundle into the infrared and visible wavelengths. Only the infrared wavelengths are permitted to pass through the filters for reflection to an infrared detector disposed between the dihedral and trihedral reflector means. The filter associated with the dihedral reflector means includes a zone of transparency which permits visible wavelengths to pass therethrough and be focused on a video detector disposed on the optical axis behind the dihedral reflector means.

Dual mode radiation transmitting apparatus

Abstract: Radiation transmitting apparatus which is smaller, lighter and less expensive than prior art systems, provides approximately 360° azimuthal coverage and has the capability of operating in an infrared countermeasure mode when in a hostile area and as a collision avoidance beacon when in a non-hostile area. In particular, a rotatable reflector is positioned adjacent a fixed infrared source within a protective member capable of being mounted to an object to be protected, such as a helicopter. In the infrared countermeasure mode of operation, the reflector is rotated at a first angular velocity. An infrared filter is positioned relative to the infrared source and the rotating reflector whereby only infrared radiation is transmitted through the protective member. In the collision avoidance mode, the reflector is rotated at a second angular velocity, less than the first angular velocity, and the infrared filter is positioned relative to the infrared source and the rotating reflector whereby visible and infrared radiation generated by the infrared source is transmitted through the protective member.

Weapon training simulator

Abstract: An apparatus for automatically determining without human intervention the intersection point of the axis of an aimable optical system with a plane. A scanning radiation source is imaged on a radiation sensor array by a movable focusing reflector. The signal output from the sensor array is electronically processed to determine the intersection point of the optical axis of the focusing reflector on a target plane. When the apparatus is used as a weapon training simulator, a shot sound synthesizer imparts additional realism.