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Showing papers on "Reflector (antenna) published in 1977"



Journal ArticleDOI
01 Oct 1977
TL;DR: A review of microwave reflector antennas with particular regard to those antennas which produce pencil-beam radiation patterns is provided in this article, where the design of dual-reflector systems is considered in depth and different computer optimisation techniques are reviewed.
Abstract: The paper provides a review of current research on microwave reflector antennas with particular regard to those antennas which produce pencil-beam radiation patterns. After a preliminary examination of microwave antennas of different types attention is focused on circularly symmetric antennas with axially symmetric feed systems. This class of antenna accounts for the largest number of applications which include microwave point-to-point communication, satellite communication, and radio astronomy. The choice of optimum feed is considered in more detail and it is demonstrated that metallic feeds with corrugated walls represent the best choice in most cases. Brief reference is also made to dielectric cone feeds which may find a place in future systems. The design of dual-reflector systems is considered in depth and different computer optimisation techniques are reviewed. These include the latest methods of diffraction optimization in which more than one of the antenna specifications is involved. An example is given where efficiency and VSWR are simultaneously optimized.

76 citations


Patent
25 Feb 1977
TL;DR: In this paper, a high intensity strobe light having reduced electromagnetic radiation is mounted on a housing designed to both reduce electromagnetic interference and protect the flash tube from the environment, and light from the flash tubes is piped to a reflector.
Abstract: A high intensity strobe light having reduced electromagnetic radiation. A ash tube is mounted on a housing designed to both reduce electromagnetic interference and protect the flash tube from the environment, and light from the flash tube is piped to a reflector. The light pipe is surrounded by a waveguide proportioned to operate below cutoff frequency thereby providing attenuation to undesirable RF radiated from the flash tube.

72 citations


Journal ArticleDOI
TL;DR: In this article, a mathematical model to simulate the performance of flat-plate collector-reflector systems is presented to predict the annual performance of a water heating system with several values of the reflector angle.

64 citations


Patent
28 Apr 1977
TL;DR: A reflector of optical radiation is on at least one radiation emitting facet of an electroluminescent device as mentioned in this paper, which includes a plurality of contiguous layers of alternating composition, each of which is of silicon and a material selected from the group consisting of aluminum oxide, magnesium fluoride and silicon dioxide.
Abstract: A reflector of optical radiation is on at least one radiation emitting facet of an electroluminescent device. The reflector includes a plurality of contiguous layers of alternating composition. The layers are of silicon and a material selected from the group consisting of aluminum oxide, magnesium fluoride and silicon dioxide. Each of the layers is approximately λ/4n in thickness where "λ" is the free space wavelength of radiation emitted from the electroluminescent device, and "n" is the index of refraction of the layer. Two of the alternating contiguous layers provide a reflector which is partially reflecting, while six of the layers provide a reflector substantially reflecting to optical radiation.

61 citations


Patent
06 Apr 1977
TL;DR: In this article, a parabolic reflector is supported by an azimuth frame supported on two wheels and a central pivotal point, which is positioned in a substantially triangular configuration.
Abstract: A parabolic reflector is supported so that it can track the sun The support for this reflector comprises an azimuth frame supported on two wheels and a central pivotal point which are positioned in a substantially triangular configuration The two wheels rotate on tracks On top of the azimuth frame, there is provided an elevation frame The elevation frame includes curved rails which define a portion of an arc and extend vertically The reflector rides on wheels captured within the curved rails The wheels of the azimuth frame are driven by an azimuth actuator The reflector structure is counterbalanced about its elevation axis by a pendulum cable system which is driven by a motor to change elevation At the focal point of the parabolic reflector, a heat engine or receiver is mounted independently on the reflector Suitable means are provided for moving the reflector about its two axes in order to track the sun

59 citations


Patent
25 Jan 1977
TL;DR: In this paper, a fixed, linear, ground-based primary reflector having an extended curved sawtooth-contoured surface covered with a metalized polymeric reflecting material, reflects solar energy to a movably supported collector that is kept at the concentrated line focus of the reflector primary.
Abstract: A fixed, linear, ground-based primary reflector having an extended curved sawtooth-contoured surface covered with a metalized 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.

57 citations


Journal ArticleDOI
TL;DR: In this paper, the design of lens-mirror combinations with maximal concentration is described, where the solution for the reflector is readily found to be compound hyperbolic, which is useful whenever concentration rather than image formation is important, for example in radiation detectors and solar energy collectors.
Abstract: By the addition of suitable reflectors the concentration of a lens can be increased to the thermodynamic limit, which is equivalent to an f-number of one half. Such lens-mirror combinations are useful whenever concentration rather than image formation is important, for example, in radiation detectors and solar energy collectors. The design of lens-mirror combinations with maximal concentration is described. To the approximation that the lens has sharp focal points at off-axis incidence, the solution for the reflector is readily found to be compound hyperbolic. With proper choice of the f-number of the lens the hyperbolic reflector reduces to a V-trough or cone, an arrangement which offers considerable advantages for fabrication. The 2-D case (line focus lens) suffers from aberrations due to focal length variation with nonplanar incidence. The optical performance of 2-D lens-mirror combinations at nonplanar incidence is analyzed and evaluated for its suitability in solar energy applications. A prototype Fresn l lens plus V-trough has been built, and test data are presented.

56 citations


Patent
23 Dec 1977
TL;DR: A multi-band multi-element directional antenna array having a driven element and at least one parasitic element with a network at the center of each element interconnecting element opposite side radiators is described in this article.
Abstract: A multi-band multi-element directional antenna array having a driven element and at least one parasitic element with a network at the center of each element interconnecting element opposite side radiators. While some of these would be a driven element and either a reflector or director parasitic element array most applications call for at least three elements, a driven element, a reflector element and a director element, and for some applications, additional parasitic director elements are added. While antenna arrays embodying features hereof may be adapted as two band f 1 f 2 , f 2 f 3 , or f 1 f 3 antenna arrays, primary useage would be in a three radio band f 1 , f 2 , f 3 version with band nominal center frequencies related, approximately by the progression 1, 1.5, 2 (example 14, 21, and 28 MHz). Reflector and director elements with their center networks as parasitic elements are structured to resonate at frequencies up to ten percent displaced from respective band operating frequencies--reflector elements at lower frequencies and directors at higher frequencies. Some of the arrays employ folded elements for improved unidirectional radiation patterns and structural advantages.

48 citations


Patent
24 Mar 1977
TL;DR: A cylindrical arc reflector of electromagnetic radiation is a rectangular sheet of material having a radiation reflective surface composed of longitudinal segments that reflect substantially all of the impingent radiation to a longitudinal focal line as discussed by the authors.
Abstract: A cylindrical arc reflector of electromagnetic radiation which is a rectangular sheet of material having a radiation reflective surface composed of longitudinal segments that reflect substantially all of the impingent radiation to a longitudinal focal line when the reflective surface is held in the form of a concave cylindrical arc by a pressure differential. The sheet is mounted by its longitudinal edges with its transverse edges movably sealed so as to form an enclosure into which a low vacuum is introduced to create the form holding pressure differential. The reflector is particularly adaptable for use in a solar energy collection apparatus that is constructed using a support structure that does not include the precisely accurate shape of the reflective surface.

47 citations


Patent
03 Feb 1977
TL;DR: In this paper, a solar energy collector system characterized by an improved concentrator for directing incident rays of solar energy on parallel vacuum-jacketed receivers or absorbers including a plurality of individually mounted reflector modules of a common asymmetrical triangular cross-sectional configuration supported for independent reorientation is defined.
Abstract: A solar energy collector system characterized by an improved concentrator for directing incident rays of solar energy on parallel vacuum-jacketed receivers or absorbers including a plurality of individually mounted reflector modules of a common asymmetrical triangular cross-sectional configuration supported for independent reorientation and defining a plurality of asymmetric vee-trough concentrators.

Patent
17 Oct 1977
TL;DR: The reflector support structure includes a plurality of substantially straight rod-like elements which are secured together at their respective ends, forming joints, in such an arrangement so as to describe a generally paraboloidal shape comprised of open triangles as discussed by the authors.
Abstract: The reflector support structure includes a plurality of substantially straight rod-like elements which are secured together at their respective ends, forming joints, in such an arrangement so as to describe a generally paraboloidal shape comprised of a plurality of open triangles. Elongated standoff elements extend outwardly from at least the joints of the reflector support structure and have secured thereto positioning elements for supporting the apexes of triangular-shaped relfecting sections. A plurality of reflecting sections are arranged to substantially mate along their respective edges, and are held in place by the supporting elements, to form a large, substantially parabolic, reflector. When the reflector and reflector support structure are used as part of a solar collection system, a tracking support structure supports the reflector support structure off the ground and in a correct orientation relative to the sun.

Patent
02 May 1977
TL;DR: In this article, an improved lamp and socket assembly is disclosed in which a socket collar is mechanically secured to the panel or reflector when the lamp is used, and the base of the lamp attaches to the collar as does the electrical connector.
Abstract: An improved lamp and socket assembly is disclosed in which a socket collar is mechanically secured to the panel or reflector when the lamp is used. The base of the lamp attaches to the collar as does the electrical connector. The combination enables a more repeatable alignment of the lamp in the panel or reflector. A compact assembly is achieved by using nested cylinders in the parts.

Patent
Meijer Roelf Jan1
07 Nov 1977
TL;DR: In this paper, a solar collector comprising a focussing reflector rotatable about an axis, an adjusting mechanism for effecting rotation of the reflector about such axis, and a solar tracking arrangement for actuating the adjusting mechanism, the solar-tracking arrangement including a pair of sun-sensor reservoirs each containing a high-pressure working medium that thermally expands when subjected to solar radiation.
Abstract: A solar collector comprising a focussing reflector rotatable about an axis; an adjusting mechanism for effecting rotation of the reflector about such axis; and a solar-tracking arrangement for actuating the adjusting mechanism, the solar-tracking arrangement including a pair of sun-sensor reservoirs each containing a high-pressure working medium that thermally expands when subjected to solar radiation.

Journal ArticleDOI
20 Jun 1977
TL;DR: In this paper, two general methods for synthesizing the excitations for a laterally displaced feed cluster are presented, one by analytical means and the other by a gradient optimization algorithm which minimizes the weighted error between an objective and the actual power patterns in the secondary pattern space.
Abstract: When a feed is displaced from the focus of a reflector, phase distortion results in the effective aperture distribution, which in turn gives rise to secondary beam distortion. In multiple beam or contour beam antennas, the feed normally consists of an array of identical elements located on a triangular lattice. Taking advantage of this arrangement, a "cluster" of feed elements instead of a single element may be used to control each beam. By adjusting the relative excitations of the elements in a cluster, the aperture phase distortion due to the feed displacement may be partially compensated. Two general methods for synthesizing the excitations for a laterally displaced feed cluster are presented. In the first method the excitations are chosen to minimize the weighted phase error in the effective aperture by analytical means. The second method determines the excitations by a gradient optimization algorithm which minimizes the weighted error between an objective and the actual power patterns in the secondary pattern space. The first method is roughly two orders of magnitude more efficient computationally than the gradient optimization algorithm, but not as flexible in application or as precise. Numerical results are presented for cluster feed designs and their application to the synthesis of contour patterns.

Patent
14 Mar 1977
TL;DR: A laser optical apparatus for operation under a microscope comprises: a laser beam introducing 45° reflector arranged between two optical axes so as not to impair the range of vision frontwardly of a binocular telescope for operation, a parabolic mirror with a surface displaced from an axis for condensing introduced beams of laser and serving as an objective lens of the microscope as discussed by the authors.
Abstract: A laser optical apparatus for operation under a microscope comprises: a laser beam introducing 45° reflector arranged between two optical axes so as not to impair the range of vision frontwardly of a binocular telescope for operation, a parabolic mirror with a surface displaced from an axis for condensing introduced beams of laser and serving as an objective lens of the microscope, a plane reflector driven by motors to direct the condensed beams of laser and an optical axis of the microscope, and a maneuvering mechanism including a stick for operating said motor.

Patent
29 Aug 1977
TL;DR: In this paper, a solar energy collector is shown which is comprised of an underlying support, a support surface, and a combined reflector and heat absorber, which is formed from a continuous sheet of material to provide contiguous parabolic reflectors, each reflector having an upstanding heat absorbing manifold centrally located in the form of a fluid conduit.
Abstract: A solar energy collector is shown which is comprised of an underlying support, a support surface, and a combined reflector and heat absorber. The combined reflector and heat absorber is formed from a continuous sheet of material to provide contiguous parabolic reflectors, each reflector having an upstanding heat absorber centrally located therein in the form of a fluid conduit. The absorber-fluid conduit is closed along one edge by the support surface or by a spacer between support surfaces. A pair of manifolds are operatively connected at the ends of the heat absorbers to enable heat-absorbing fluid to flow in from one manifold, through the absorber-conduits, and out the other manifold. The continuous formation of the parabolic reflectors and heat absorbers from one sheet provides production economies, manufacturing efficiencies and reduced weight and cost of the solar energy collector.

Patent
09 Aug 1977
TL;DR: In this paper, a solar energy reflecting system which can modify its reflector configuration in accordance with the movement of the sun across the sky is presented, which includes a circular dish-like housing with upper and lower circular hoops in spaced relationship within the housing which can be displaced relative to each other.
Abstract: A solar energy reflecting system which can modify its reflector configuration in accordance with the movement of the sun across the sky. The system includes a circular dish-like housing with upper and lower circular hoops in spaced relationship within the housing which can be displaced relative to each other. A series of reflector panels are sequentially spaced around the peripheral wall of the dish like housing and controlled by the displacement of the upper and lower hoops to lie in an outwardly flared direction and pivot as the hoops are displaced relative to each other. A sensing device detects the position of the sun in the sky and accordingly displaces the hoops to thereby pivot the reflector panels appropriately to give the proper reflector configuration which will provide the best focusing of the sunlight and concentrate it onto a heating coil where the heat can be absorbed and transferred to a storage tank.

Patent
08 Aug 1977
TL;DR: In this article, a solar energy reflector formed of a rigid frame that supported a thin reflective sheet and retains the sheet in a parabolic or like concave shape notwithstanding severe wind or like loads is presented.
Abstract: A solar energy reflector formed of a rigid frame that supports a thin reflective sheet and retains the sheet in a parabolic or like concave shape notwithstanding severe wind or like loads. The frame includes rigid end plates that define slots that have portions concentric with the focal axis of the parabolic surface so that the reflector can be installed onto and removed from a fixed water carrying pipe without disturbing the plumbing connections to the pipe. A drive system and solar energy sensor circuit connected thereto for assuring that the reflector is aimed at the sun throughout its traverse of the sky from dawn to dusk. A protective cover for the solar collector which both protects the highly reflective surface against deterioration and contributes to the overall strength of the collector.

Patent
21 Jan 1977
TL;DR: In this paper, the authors describe a semiconductor device which utilizes interferometric principles and electrical control to provide either light reflection or light transmission or partial light reflection/transmission.
Abstract: A semiconductor device which utilizes interferometric principles and electrical control to provide either light reflection or light transmission or partial light reflection/transmission. In a preferred embodiment, the device includes an input waveguide which divides into branch waveguides, with the branch waveguides being reunited at an output waveguide. When the optical path lengths of the branched waveguides varies by an integer multiple of the light wavelength in the guides, the light waves interfere constructively at the output waveguide causing light to be transmitted into the output waveguide. When the light wave in one branch waveguide undergoes a single pass phase shift of 180° relative to the light wave in the other branch waveguide, the light waves interfere at the output waveguide and are caused to return to the input waveguide through the branch waveguides. The returning light wave in the one branch waveguide once again experiences a single pass 180° phase shift relative to the light wave in the other branch waveguide such that the light waves are in phase at the input waveguide and the device appears as a reflector to a light source coupled to the input waveguide. Electrodes may be applied to one or both branch waveguides. Upon application of an electric field to the electrodes the relative optical path lengths of the branched waveguides will be changed allowing electrical control of the strength of the light reflection or transmission.

Journal ArticleDOI
TL;DR: The Eimac illuminator series as mentioned in this paper is a variant of the conventional short arc lamp, having an integral parabolic (or elliptical) reflector, which provides greatly improved light gathering efficiency over more simple arc lamps.
Abstract: : High-pressure xenon short-arc lamps have long been considered to be reliable, high intensity sources of radiation for the ultraviolet, visible, and near-infrared spectral regions. The Eimac illuminator series, which Varian began marketing in 1972, is a variant of the conventional short arc lamp, having an integral parabolic (or elliptical) reflector, which provides greatly improved light gathering efficiency over more simple arc lamps. The integral reflector also significantly simplifies lamp alignment.

Patent
28 Apr 1977
TL;DR: In this article, a fixed flat plate solar reflectors and collectors were used to increase the efficiency of a solar reflector during a year-long use, and a novel arrangement of fixed flat-plate reflectors was proposed.
Abstract: The invention relates generally to a novel arrangement of fixed flat plate solar reflectors and collectors whereby an increased efficiency is obtained during year-long use.

Patent
21 Oct 1977
TL;DR: In this paper, an improved drive and control system for the heliostat reflector assembly is presented, which is controllably driven in a predetermined way by a light-weight drive system so as to be angularly adjustable in both elevation and azimuth.
Abstract: A heliostat for a solar receiver system comprises an improved drive and control system for the heliostat reflector assembly The heliostat reflector assembly is controllably driven in a predetermined way by a light-weight drive system so as to be angularly adjustable in both elevation and azimuth to track the sun and efficiently continuously reflect the sun's rays to a focal zone, ie, heat receiver, which forms part of a solar energy utilization system, such as a solar energy fueled electrical power generation system The improved drive system includes linear stepping motors which comprise low weight, low cost, electronic pulse driven components One embodiment comprises linear stepping motors controlled by a programmed, electronic microprocessor Another embodiment comprises a tape driven system controlled by a position control magnetic tape

Patent
06 May 1977
TL;DR: In this article, the Si rod has a cylindrical pn-junction formed between a p-type core and an n-type outer layer, and the core's resistivity lies between 0.01 and 10 ohms/cm.
Abstract: The solar photoelectric converter converts solar radiation into electrical energy using a distributed photosensitive diode consisting of a rod of silicon 2 to 4 mm in dia. The Si rod (1) has a cylindrical pn-junction formed between a p-type (or n-type) core and an n-type (or p-type) outer layer. The core's resistivity lies between 0.01 and 10 ohms/cm. The rod is located at the foci of a cylindrical lens (22) and a concave cylindrical reflector (14). Several such rods lie each parallel behind their own cylindrical lens (which forms a continuous corrugated sheet with other lenses) and their own reflector (again continuous).

Patent
14 Mar 1977
TL;DR: A light-collecting reflector for use with a source of light comprises a main reflector having a central parabolic reflecting surface and an outer ellipsoidal reflecting surface surrounding the central surface as discussed by the authors.
Abstract: A light-collecting reflector for use with a source of light comprises a main reflector having a central parabolic reflecting surface and an outer ellipsoidal reflecting surface surrounding the central surface The main reflector is adapted to have a source of light placed along its central axis A secondary reflector having a reflecting surface facing the reflector surfaces of the main reflector and having an open central portion to allow light to pass therethrough, is positioned in front of the main reflector so that light striking the reflector surface of the secondary reflector is reflected back toward the reflecting surfaces of the main reflector The reflecting surface of the secondary reflector is arcuate with radii that emanate from a circle which is concentric with the center axis of the main reflector

Patent
14 Apr 1977
TL;DR: A corner reflector can be made by molding individual pas with a plurality of corner reflectors formed in each panel, joining the panels in a desired shape and filling the central portion of the target reflector formed thereby with a buoyant material as discussed by the authors.
Abstract: A corner reflector and method of making the same by molding individual pas with a plurality of corner reflectors formed in each panel, joining the panels in a desired shape and filling the central portion of the target reflector formed thereby with a buoyant material.

Patent
22 Dec 1977
TL;DR: A solar energy collection apparatus has a reflector for reflecting the rays of sunlight incident thereupon to, and concentrating them upon, an absorber as discussed by the authors, which can be readily adjusted for other periods of time throughout the year by changing the length of the support struts.
Abstract: A solar energy collection apparatus has a reflector for reflecting the rays of sunlight incident thereupon to, and concentrating them upon, an absorber. Mounting blocks insulate and position the reflector and absorber with respect to each other and to support struts. Due to a wide angle of acceptance of the apparatus, the rays of the sun are collected for a substantial part of a day as well as for a period of time of many days or months. Additionally, the reflector-absorber assembly can be readily adjusted for other periods of time throughout the year by changing the length of the support struts.

Journal ArticleDOI
TL;DR: In this paper, the reflection and bulk-wave loss characteristics of a SAW grooved reflector array are treated using an approach which integrates field theory with the theory of two-mode coupling well-known in the area of optical gratings.
Abstract: The reflection and bulk-wave loss characteristics of a SAW grooved reflector array are treated using an approach which integrates field theory with the theory of two-mode coupling well-known in the area of optical gratings. The present treatment offers the following distinct advantages over the previously reported equivalent network approach: i) it derives the array characteristics directly in terms of the material constants of the substrate; ii) it provides quantitative information on the power loss resulting from bulk-wave radiation; and iii) it can readily and accurately accommodate changes in groove profile or height among the individual array elements, making this approach amenable for use in the design of tapered arrays. Computed SAW scattering characteristics of a uniform reflector array comprised of a varying number of trapezoidal (but almost rectangular) grooves are presented. I

Patent
26 Sep 1977
TL;DR: In this article, an improved electromagnetic radiation collector system for concentrating electromagnetic radiation emitted from a source to a collecting mechanism is described, which includes a plurality of primary reflectors which are moveable actuated responsive to a displacement of the electromagnetic radiation source.
Abstract: An improved electromagnetic radiation collector system for concentrating electromagnetic radiation emitted from a source to a collecting mechanism. The radiation collector system includes a plurality of primary reflectors which are moveably actuated responsive to a displacement of the electromagnetic radiation source. The primary reflector members reflect and concentrate the source emitted radiation to a secondary reflector which is positionally located substantially at the focal length of the displaceable primary reflector members or plates. The secondary reflector is particularly contoured and reflectively coated to reflect the initially concentrated reflected radiation to a substantially line focus. The secondary reflector may be stationary or formed of a plurality of rotatable reflecting members. Radiation reflected from the secondary reflector is focused upon a line collector mechanism or heating a fluid medium passing therethrough. Additionally, the second reflector may reflect radiation to a light redirecting mechanism having an absorbing face substantially located along the focus line of the secondary reflector elements.

Patent
12 May 1977
TL;DR: In this article, a solar energy collector is described, which consists of a pipe interconnecting lower and upper headers, the upper header structurally supporting the pipe, a parabolic reflector is supported by the pipe and a fluid is movable through the pipe from one header to another for receiving the solar energy focused upon the pipe by the reflector.
Abstract: A solar energy collector is disclosed herein which comprises a pipe interconnecting lower and upper headers, the upper header structurally supporting the pipe. The pipe extends within an opening in the lower header and includes an exterior shoulder which rests upon the lower header. The other end of the pipe includes an exterior shoulder, the pipe extending into an opening in the upper header. A spring rests on the shoulder on the upper end of the pipe and holds a combination bearing and fluid seal against the upper header. A parabolic reflector is supported by the pipe, and a fluid is movable through the pipe from one header to the other for receiving the solar energy focused upon the pipe by the reflector. The pipe is operable to rotate to direct the reflector toward the sun.