Showing papers on "Reflector (antenna) published in 1996"

Plural frequency antenna feed

Abstract: Apparatus and method for providing an antenna feed (10) operative at different microwave frequency bands employ a circular waveguide (14) interconnecting an orthomode transducer (20) to a feed horn (16) thereby providing a feed (10) suitable for illuminating the reflector (54) of an antenna (12). The orthomode transducer provides for a coupling of waves in the first frequency band with both vertical and horizontally polarized waves. Included within the feed is a coupler assembly (26) of waves of the second frequency band operative via a sidewall of the circular waveguide. The coupler assembly includes plural identical coupling sections (28) each having a rectangular waveguide section contiguous and parallel to the circular waveguide with a row of apertures for coupling power into and out of the circular waveguide. Pairs of the coupling sections are disposed in orthogonal planes so as to introduce two linearly polarized waves which are perpendicular to each other. A slab (48) of dielectric material is placed in each of the coupling sections to match the phase velocity of waves in the coupling sections to waves in the circular waveguide at the second frequency band while mismatching the phase velocities at the first frequency band. The dispersion of the waveguides provides for interaction with electromagnetic waves in the second frequency band while inhibiting such interaction at the first frequency band.

Light emitting device utilizing a periodic dielectric structure

Abstract: A light emitting device comprising a substrate and a dielectric structure having at least a two-dimensionally periodic variation of dielectric constant which exhibits a spectrum of electromagnetic modes including guided modes of frequencies below a predetermined frequency cutoff and radiation modes of frequencies above and below said predetermined frequency cutoff, the two-dimensionally periodic variation of dielectric constant of the dielectric structure introducing a band gap between the guided modes. A radiation source, such as a quantum well, is associated with said structure, and generates electromagnetic radiation which couples to the radiation modes resulting in radiation extraction from the structure. The band gap allows the radiation to couple to radiation modes rather than to guided modes resulting in radiation extraction from the structure. The structure can be fabricated such that a radiation reflector is disposed between the structure and the substrate.

Low sidelobe reflector antenna system employing a corrugated subreflector

Abstract: An improved subreflector antenna with lower sidelobes than prior art subreflector antennas is disclosed herein A tapered, anisotropic, corrugated subreflector is attached to a waveguide and located at the focus of a near-parabolic deep dish main reflector The subreflector has corrugations of varying depth The varying depths of the corrugations result in varying reactance, or reactance taper, of the subreflector This taper is designed in such a manner to guide or steer the energy from the antenna feed to the main reflector in such a manner as to help assure sharply reduced sidelobes Further, the subreflector is physically shaped so as to further steer or guide the energy in the desired direction The deep geometry of the main reflector allows the reduced sized subreflector to be positioned within the rim of the main reflector such that the combination can be covered by a flat radome

Semiconductor laser with integral spatial mode filter

Abstract: A semiconductor laser having a light amplifying diode heterostructure with a flared gain region in an external resonant cavity. The flared gain region has a narrow aperture end which may be coupled to a single mode waveguide and a wide output end. A light emitting surface of the heterostructure proximate to the wide end of the flared gain region is partially reflective and combines with an external reflector to form a resonant cavity that is effectively unstable. The intracavity light-emitting surface proximate to the narrow aperture end is antireflection coated. The external reflector may be a planar mirror or a grating reflector. A lens or an optical fiber may couple the aperture end of the flared gain region to the external reflector. Frequency-selective feedback is provided by orienting the grating reflector or providing a prism in the cavity in front of the external planar mirror. Other filtering elements may also be placed in the external cavity. The flared gain region and waveguide may be differentially pumped or modulated with current provided by separate contacts.

Ultra lightweight thin membrane antenna reflector

Abstract: A space antenna reflector (10) comprising composite membranes (26) having a fabric core comprising high modulus fibers, such as of graphite, woven along three or more axes and encapsulated within a cured plastic as a single ply composite material, such reflectors having quasi isotropic strength properties, i.e., the same strength, thermal stability and distortion-resistance in substantially all directions although they are based upon a single, lightweight ply of woven graphite fabric (24). The present reflectors may have a moulded or honeycomb support, for attachment to a spacecraft or satellite.

Microwave planar aerial for satellite reception

Abstract: The aerial (1) consists of smaller multiple reflector aerials (10) on a frame (15). Each aerial has a feed (12) connected to a hollow wave guide (11) leading to receivers. These receivers can either be dipoles or strip line emitters with surface resonators to receive horizontal and vertical polarised microwaves. A single receiver-converter (5) is attached to the receivers to combine the transmissions.

Directing and concentrating solar energy collectors

Abstract: A directing and concentrating solar energy collector with a concentrating reflector and one or more cooperating directing reflectors concentrates solar radiation to a substantially narrow and straight line of concentration The directing reflectors, being perpendicular to the concentrating reflector, confine the zones of concentration at the line of concentration A stationary optimizing energy converter having multiple energy conversion sections receives the concentrated radiation, converts part of it to electricity, with another part to thermal energy A building includes multiple collectors in an energy collection system, with one variation of the collectors used under a transparent roof and another inside a transparent wall The concentrating reflector is provided either with single axis tracking, or with no tracking at all, enabling different installations and having different advantages For the tracking versions, a radiation scanner digitally measures and computes the most optimal angular tracking position for accurate adjustment of the concentrating reflectors, yielding the highest available energy level Software in a micro processor controls the collection system and the conversion sections, independently from each other, optimizing the energy collection process The software also reads radiation energy levels from the radiation sensors of the scanner, at regular angular intervals of the rotation of the rod, and computes the most optimal angular tracking adjustment for positioning of the concentrating reflectors of all collectors

Omnidirectional and directional antenna assembly

Abstract: An antenna assembly providing selectable omnidirectional or directional reception of radio transmissions in a frequency band in accordance with the invention includes an electrically conductive reflector (432) defining a cavity (702) having a bottom (708), an opening (714) and a surface (704 and 706) extending from the bottom to the opening and an electrical output (763); an electrically conductive loop (431) coupled to ground and having an electrical outlet (766) for coupling to an RF amplifier (407), the loop being positioned between the bottom opening of the cavity; a RF switch (406) having an input (760) and first and second outputs (762 and 764), the RF switch having a first switching state electrically connecting the input to the first output and a second switching state electrically connecting the input to the second output, the first switch output being electrically coupled to ground and the second switch output being electrically coupled to the output of the electrically conductive loop; and wherein the first switching state provides the directional reception and the second switching state provides the omnidirectional reception of the radio transmissions.

Method of non-contact micromanipulation using ultrasound

Abstract: A method of non-contact micromanipulation using ultrasound includes providing a concave ultrasound transducer in a liquid medium in which micro particles are distributed, positioning a reflector at the focal point position of the transducer and radiating ultrasound from the transducer to form a standing wave field between the transducer and the reflector to align and trap micro particles at half wavelength intervals along the axis of the transducer.

Backlight system with multilayer optical film reflector

Abstract: The present invention includes a backlight system incorporating a back reflector and/or a lamp cavity reflector constructed of a multilayer optical film.

Collimator for x-ray spectroscopy

Abstract: The invention comprises an x-ray collimator and its fabrication process. The collimator displays the general shape of a tube having an entrance aperture and an exit aperture. The walls of the collimator tube are not are not parallel to each other but rather are paraboloudal in longitudinal section resulting in a tube whose entrance aperture is of a smaller diameter than its exit aperture. The preferred embodiment comprises a first tutular paraboloid (10), or first reflector, and a second tubular paraboloid (12), or second reflector, each having an outer surface and an ultrasmooth reflecting inner surface. The second reflector is of smaller diameter than the first reflector and is held by suitable means concentrically with the first reflector.

Laser wavelength control system

Abstract: A laser wavelength control system (20) stabilizes laser output wavelength. The control system includes a reflector/filter device (40) upon which laser radiation is incident for yielding both a filtered-transmitted signal (FS) and a reflected signal (RS). A controller (45) uses both the filtered-transmitted signal (FS) and the reflected signal (RS) to generate a control signal (CS). The control signal is utilized by a temperature converter (100) to adjust laser output wavelength of the laser (22). In one embodiment, the reflector/filter device is an optical fiber grating. The wavelength control system facilitates construction of a modular optical multichannel transmission system (200).

Optically based position location system for an autonomous guided vehicle

Abstract: An optically based position location system, comprises multiple reflectorsositioned at known locations in an environment; a vehicle for traveling along a path in the environment; a first sensor for generating and detecting a collimated and polarized first light signal reflected from one of the reflectors, and for generating a first output signal in response to detecting the first light signal; a second sensor for generating and detecting a collimated and polarized second light signal reflected from the reflector reflecting the first light signal, and for generating a second output signal in response to detecting the second light signal; and a data processor which uses the first and second output signals for determining the distance between a reference coordinate on the vehicle and the reflector.

Micromolded integrated ceramic light reflector

Abstract: A micromolded integrated ceramic light reflector which can be totally integrated with drive and control electronics embedded on the same substrate for use with image projection systems. Each light reflector can be molded to a size on the order of less than one (1) mm3 using the method of the present invention. Each light reflector includes a ceramic base element with a cavity and one surface thereof. A beam extends from one end of the cavity and cantilevers out therefrom above the cavity. The beam is made from the same ceramic as the base element and is coated with an electrically conductive ceramic coating which is also a good reflector of the visible radiation spectrum. The base of the cavity is coated with the same electrically conductive ceramic, or with a metallic coating. In either case, the coating is electrically grounded. When the beam is in its normal, undeflected position, light incident on the top surface of the beam reflects at a first angle. When a potential is applied to the activation electrode, the beam is deflected downward into the cavity. In this position, light incident on the beam reflects at a second angle. Thus, control of the light output to a given surface over a small spot (pixel) is achieved by controlling the potential across the ceramic light reflector.

Reflector, reflective liquid crystal display incorporating the same and method for fabricating the same

Abstract: A reflector including a substrate and a thin metal film is provided. The substrate defines a plurality of randomly arranged, curved, surface deformity portions, each having an asymmetric cross section. Typically, the surface deformity/substrate structure is formed by creating curved pieces of resist material on a substrate, and thereafter, tilting and heating the substrate. Alternatively, a photoresist process utilizing an ion, or an electron beam without heating, can be used. The metal film is coated onto the surface of the substrate and onto the curved, surface deformities located thereon, such that light incident from a given direction is reflected over a wide range, but most intensely in particular directions. Further, a liquid crystal display is provided in which the reflector just mentioned is used as a lower substrate. An upper glass substrate is provided, and a liquid crystal display medium is interposed between the reflector and the upper glass substrate. In some embodiments, the liquid crystal display medium includes a matrix of polymer walls formed either by light irradiation using a mask, or by cooling a mixture of liquid crystal material, and a polymerizable precursor to separate phases prior to light irradiation. In addition, a phase plate, a polarizer, an insulating layer, display electrodes and/or color filters may be utilized in association with the liquid crystal display. Also, the liquid crystal material, the surface of the reflector substrate, and/or the thin metallic film may be divided into areas corresponding to individual pixels.

Optical time domain reflectometer with internal reference reflector

Abstract: An optical time domain reflectometer suitable for determining its front panel insertion loss comprises a four-port coupler having first and second ports connected to a light source and an optical detector, respectively, and third and fourth ports connected to a front panel connector and a reference reflector, respectively. In use, a fiber-under-test is connected to the front panel connector. The coupler splits light from the light source between the front panel connector and the reference reflector and couples light returning from the front panel connector and reflector to the detector. The optical path between the front panel connector and the coupler is longer than the optical path between the reference reflector and the coupler by such a distance that a Fresnel reflection pulse from the reference reflector, produced by a pulse emitted by the light source, will be received by the detector before a corresponding reflection pulse returned from the front panel connector. In order to ensure that the two reflection pulses can be distinguished from each other, the difference between the two optical paths is greater than a distance equal to an event dead zone for the particular width of pulse supplied by said light source. The reference reflector comprises an end portion of a length of optical fiber, preferably encapsulated with a material having a refractive index different from that of the length of optical fiber. The OTDR facilitates miniaturization because it avoids the use of an internal length of reference fiber.

Component device for optical communication

Abstract: A component device for optical communication comprising a reflector and a lens. The reflector is in the form of a deep dish with a height B of 0.2-0.4 mm, a bottom diameter A of 0.7-1.1 mm and the side wall having an angle C of 40-85 degrees. The lens is a hemisphere formed on the reflector, with the apex distant from the bottom surface of the reflector by a height D of 4.5-5.0 mm. The hemisphere has a radius R of 2.4-2.8 mm. A thin miniature lamp is provided that is improved in leadframe design such that the advantages of the conventional 5 mm.sup.φ are retained, while its height is reduced to less than 5.5 mm. In addition, it is capable of achieving an effective luminous intensity distribution pattern of a light beam, which is one of the major characteristics required in data communication.

Optical reading device

Abstract: A small-sized optical reading device for performing the high-speed optical scanning of an object to be read, and for returning light irregularly reflected by the object. In this device, a first reflector element is driven in such a manner as to perform reciprocative rotations or vibrations clockwise and counterclockwise. Further, a medium, on which a bar code, namely, the object is recorded, is scanned by light beams reflected by the first reflector element. The light beams irregularly reflected by the medium are returned to a reflector element array consisting of second reflector elements of a reciprocative vibration reflector. Independent drive signals are provided concurrently to the first reflector element and the reflector element array. The reflecting surface of the first reflector element has a size sufficient to the extent that the entire spotlight caused by a semiconductor laser can be reflected. The reflector elements, which have widths sufficient to the extent that the light beams irregularly reflected by the medium can be further reflected by the reflector elements, are arranged in a scanning direction.

Small volume dual offset reflector antenna

Abstract: The problem of reducing the size of a dual offset Cassegrain reflector type microwave antenna without adversely affecting performance while retaining the simplicity of the main reflector's (1) and subreflector's (3) traditional simple surface curvatures is solved by having the paraboloidal shaped main reflector's focal length, fm, and diameter, D, fulfil the criteria that the ratio of fm to D is less than 1.0; and in which the hyperboloidal shaped subreflector (3) is oriented so that its left foci, at which the microwave feed (5) aperture is placed, lies above the main reflector's focal axis. It's subreflector subtends an angular arc about the focal point that is slightly larger than the corresponding arc subtended by the main reflector. The elegance of the compact antenna is demonstrated by improved performance, attaining efficiencies in excess of seventy three percent.

Effects of external reflector alignment in sensing applications of optical feedback in laser diodes

Abstract: The alignment of the components in sensor systems based on external optical feedback is a critical factor due to the small size of laser aperture into which the returned light must be coupled. This paper presents experimental results and a theoretical explanation which show that the fringe frequency of a self-mixing interferometric sensor system can be doubled due to misalignment of the external reflector. The double frequency fringes are less sensitive to the alignment of the reflector than the normal fringes and offer a potential increase in the resolution of a sensing system of a factor of two.

Active Shape Control of a Deployable Space Antenna Reflector

Abstract: Feasibility of active shape formation or correction of a deployable space antenna reflector under the conditions of limited number of actuators and limited information of its surface shape is investigated to aim to suppress its deformations mainly due to thermal loads. Those conditions are practical for actual development of large space antennas. A reflector surface control scheme through checking electrical radiation patterns, instead of measuring structural surface, is also proposed, and its performance is evaluated through numerical simulations.

Antenna for use with a portable radio apparatus

Abstract: An antenna for use in a portable radio apparatus, which has a pair of bands extending from the main body of the apparatus, for securing the apparatus to a user. A first antenna conductor supplied with power and a second antenna conductor not supplied with power are embedded in each band and extend parallel to the axis of the band. The first and second antenna conductors embedded in the first band are connected at one end to the first and second antenna conductors embedded in the second band. No load is connected to the second antenna conductor embedded in each band. The second antenna conductor embedded in each band performs different functions according to its length. If it has a length equal to or greater than half the wavelength λ of waves to receive, it will function as a reflector. If it has a length less than half the wavelength λ of the waves, it will function as a director. The four antenna conductors are adjusted in length and position, constituting an antenna which has high sensitivity and which is small enough to be incorporated into a portable radio apparatus.

Electronic distance measuring device

Abstract: An electronic distance measuring device that measures a distance from the electronic distance measuring device to an objective station. The electronic distance measuring device includes a radiation source for emitting frequency-modulated radiation towards a reflector disposed at the objective station, and a detector for detecting radiation reflected by the reflector. The distance of the objective station from the electronic distance measuring device is then calculated in accordance with the detected radiation. At least one radiation attenuating filter is positioned in a radiation path between the radiation source and the detector. The radiation attenuating filter is inclined with respect to a main axis of the radiation path so as to prevent incidence on the detector of an irregular reflection of the radiation by the attenuating filter.

Antenna Engineering Using Physical Optics: Practical CAD Techniques and Software

Abstract: From the Publisher: Spend less time setting up complex antenna design problems and improve the accuracy of your results with this practical new book and software package. It shows you how to combine physical optics modeling techniques with the free space dyadic Green's function to quickly and easily calculate antenna patterns and diffraction from nearby objects, letting your PC do the specialized math for you. Accompanying software created in MATLAB® and traditional FORTRAN code shows you how to apply basic routines so you can focus more time on the actual solution of antenna radiation problems. The book includes detailed examples showing you how to string the subroutines together for fast, accurate analysis of multiple reflector antennas, radomes, lenses, RCS of simple surfaces, microstrip arrays, and more. Packed with 100 illustrations and more than 120 equations, this hands-on guide is essential reading for all antenna design engineers who need powerful, versatile techniques to solve antenna radiation problems and who want to avoid complicated and potentially inaccurate math.

Laser rotary irradiating system for irradiating a laser beam

Abstract: Laser rotary irradiating system comprising a rotary irradiating system main unit and object reflectors including at least a first object reflector and a second object reflector. The rotary irradiating system main unit comprises a rotating and irradiating an irradiation light beam toward the object reflectors, a detector for detecting a reflection light beam reflected from the object reflectors and entering the rotary irradiating system main unit via the rotating unit, and a reflection light detection circuit for identifying the object reflectors from an output of the detector. The position and range of the scanning of the laser beam are determined based on the results of the detection, whereby each of the reflection surfaces of the object reflectors is divided into at least two portions, an irradiation position is confirmed by the first object reflector while the scanning position is confirmed by the second object reflector, and an irradiation light beam is irradiated for reciprocal scanning.

IR heating lamp array with reflectors modified by removal of segments thereof

Abstract: Conventional infrared, spot reflector lamps are modified by removing portions of the reflector to form reflector edges and then placing the reflector edges next to each other to form an array of lamps with a wide variety of configurations. The combined lamps are particularly effective when the filaments of each lamp are oriented in the same direction as that of a desired heating line. Maximum energy flux density is achieved by positioning the lamps at a distance of about twice the focal length of the uncut, spot-focused lamps. By removing segments from the reflectors to form edges that define planes that are parallel to or intersect with each other, various shaped reflectors are formed that are used to assemble arrays that provide uniform heating lines of various shapes.

Tailored reflectors for illumination.

Abstract: We report on tailored reflector design methods that allow the placement of general illumination patterns onto a target plane. The use of a new integral design method based on the edge-ray principle of nonimaging optics gives much more compact reflector shapes by eliminating the need for a gap between the source and the reflector profile. In addition, the reflectivity of the reflector is incorporated as a design parameter. We show the performance of design for constant irradiance on a distant plane, and we show how a leading-edge-ray method may be used to achieve general illumination patterns on nearby targets.

Headlight for vehicle

Abstract: A headlight for vehicles has a light source, a reflector having at least two different reflector regions including a first reflector region which reflects a light emitted by the light source as a converging light beam to form low beam and a second reflector region formed so that light emitted by the light source and reflected by the second reflector region together with the light emitted by the light source and reflected by the first reflector region form high beam, a lens arranged after the reflector in a light outlet direction so that at least the light which forms low beam passes through the lens, and a screening device arranged between the reflector and the lens, the screening device having a stationary screening part and a movable screening part, the movable screening part being movable between a position for low beam in which light forming low beam can pass along the movable screening part and a position for high beam in which additionally the light reflected by the second reflector region can pass along the movable screening part at least partially, so that in the position for low beam an edge of the screening device forms a bright-dark limit of low beam, the screening parts each having a plurality of openings formed so that in the position of the movable screening part for low beam the movable screening part covers the openings of the stationary screening part, and in the position for high beam the openings of the movable screening part coincide with the openings of the stationary screening part at least approximately so that the screening device forms throughgoing openings for the light

Saturable Bragg reflector

Abstract: Low optical loss and simplified fabrication are achieved by a nonlinear reflector which incorporates one or more semiconductor quantum wells within a standard semiconductor quarter wave stack reflector. The nonlinear reflector provides an intensity dependent response which permits it to be used for saturable absorption directly in a main oscillating cavity of a laser. Saturation intensity of the nonlinear reflector and thereby related laser modelocking properties can be controlled by disposing the quantum well at a particular position in the reflector structure.

Dual reflector lighting system

Abstract: A dual reflector lighting system (10) having a housing, a ballast and a lamp socket (16) connected to receive a gaseous discharge or high intensity discharge (HID) lamp (14). An outer reflector (21) is mounted to the housing to reflect a portion of light from the lamp (14). An inner or auxiliary reflector (22) is mounted coaxially with the lamp (14) to reflect a substantial amount of light from the lamp (14) downwardly. The auxiliary reflector (22) is preferably adjustable relative to the lamp (14). The invention also covers a dual reflector assembly, including an outer reflector (21) and inner reflector (22), adjustable relative to each other which is adapted to be mounted to a HID fixture. The invention also covers an auxiliary reflector (22) having a predetermined size and shape adapted to fit within an outer reflector (21) of a HID fixture and preferably includes facilities for adjusting the auxiliary reflector (22) relative to the outer reflector (21).