Showing papers on "Reflector (antenna) published in 2007"

System and apparatus for high data rate wireless communications

Abstract: A system and apparatus including a wireless network architecture that provides broadband data network coverage over an expandable geographic area. A media access control layer is also provided that facilitates access to the broadband wireless network. A high-frequency wireless modem enables high data rate access to the wireless network in a spectrally-efficient manner using SSB modulation. A wideband millimeter-wave antenna includes a cosecant-squared reflector enabling signal propagation between network elements thereby enabling seamless wireless communications. A millimeter-wave polarizer, and a septum polarizer each convert between linear and circular polarization. A cross-shaped horn antenna adapted for circularly polarized signals can also be used in combination with the septum polarizer. A combined horn antenna is fed using a microstrip patch antenna.

Antenna arrangement, in particular for a mobile radio base station

Abstract: An improved antenna arrangement is distinguished by the following features: - the reflector arrangement has a printed circuit board (5) with an electrically conductive ground plane (7), the reflector arrangement also has a reflector frame (11) with a coupling surface (13), the coupling surface (13) is capacitively coupled to the ground plane (7), the coupling surface (13) has a recess (13a) via which the ground plane (7), which is located underneath it, and/or the printed circuit board (5) or an isolating intermediate layer which is provided above the ground plane (7) or an isolating intermediate layer which is provided above the printed circuit board (5) is exposed, and the at least one antenna element arrangement (3) is positioned and/or held on the printed circuit board (5) in the area of the recess (13a).

Self-supporting unitary feed assembly

Abstract: A feed assembly for a reflector antenna having a unitary portion of dielectric material, a proximal end of the unitary portion configured for connection with the reflector antenna. The unitary portion having a waveguide portion extending between the proximal end and a sub reflector support having a sub reflector surface at a distal end. The waveguide portion and the sub reflector surface covered with an RF reflective material. The unitary portion may be cost effectively formed via, for example injection molding and or machining. Alternatively, the feed assembly may be formed as a horn feed, without a sub reflector.

Low profile side emitting LED

Abstract: Low profile, side-emitting LEDs (10) are described, where all light is efficiently emitted within a relatively narrow angle generally parallel to the surface of the light- generating active layer (14). The LEDs enable the creation of very thin backlights for backlighting an LCD. In one embodiment, the LED is a flip chip with the n and p electrodes (18) on the same side of the LED, and the LED is mounted electrode-side down on a submount (22). A reflector (34) is provided on the top surface of the LED so that light impinging on the reflector is reflected back toward the active layer (14) and eventually exits through a side surface of the LED. A waveguide layer (30) and/or one or more phosphors layers are deposed between the semiconductor layers (12, 14, 16) and the reflector for increasing the side emission area for increased efficiency. Side-emitting LEDs with a thickness of between 0.2-0.4 mm can be created.

Advanced Reflector Characterization with Ultrasonic Phased Arrays in NDE Applications

Abstract: Ultrasonic arrays are increasingly widely used in nondestructive evaluation (NDE) due to their greater flexibility and potentially superior performance compared to conventional monolithic probes. The characterization of small defects remains a challenge for NDE and is of great importance for determining the impact of a defect on the integrity of a structure. In this paper, a technique for characterizing reflectors with subwavelength dimensions is described. This is achieved by post-processing the complete data set of time traces obtained from an ultrasonic array using two algorithms. The first algorithm is used to obtain information about reflector orientation and the second algorithm is used to distinguish between point-like reflectors that reflect uniformly in all directions and specular reflectors that have distinct orientations. Experimental results are presented using a commercial 64-element, 5-MHZ array on two aluminum test specimens that contain a number of machined slots and side-drilled holes. The results show that the orientation of 1-mm-long slots can be determined to within a few degrees and that the signals from 1-mm-long slots can be distinguished from that from a 1-mm-diameter circular hole. Techniques for quantifying both the orientation and the specularity of measured signals are presented and the effect of processing parameters on the accuracy of results is discussed.

Semiconductor light-emitting device

Abstract: An object of the present invention is to provide a light-emitting device with a high output and a high efficiency by improving the efficiency for utilizing light emitted from a semiconductor light-emitting element. The inventive semiconductor light-emitting device comprises a package substrate, a sub-mount provided on the package substrate, a semiconductor light-emitting element provided on the sub-mount, and a reflector surrounding the sub-mount and the semiconductor light-emitting element, wherein the positions and sizes of the sub-mount, light-emitting element and reflector satisfy the following relationship (A) on a cross section perpendicular to the package substrate that passes through the center of the semiconductor light-emitting element, r - ls ≤ (hs - d) x (ls - lc) /hc --- (A) wherein r, ls and lc are distances from the drooping portion of the reflector, form the outer circumference of the sub-mount and from the outer circumference of the semiconductor light-emitting element to the center of the semiconductor light-emitting element, respectively, hs and d are heights of the sub-mount and of the drooping portion of the reflector, respectively, and hc is a height of the upper surface of the semiconductor light-emitting element from the upper surface of the sub-mount.

Direct evidence for continuous radar reflector originating from changes in crystal-orientation fabric

Abstract: . The origin of a strong continuous radar reflector observed with airborne radio-echo sounding (RES) at the EPICA deep-drilling site in Dronning Maud Land, Antarctica, is identified as a transition in crystal fabric orientation from a vertical girdle to an increased single-pole orientation seen along the ice core. The reflector is observed with a 60 ns and 600 ns long pulse at a frequency of 150 MHz, spans one pulse length, is continuous over 5 km, and occurs at a depth of about 2025–2045 m at the drill site. Changes in conductivity as reflector origin are excluded by investigating the ice-core profile, synthetic RES data, and a RES profile with different electromagnetic polarisation azimuths. The reflector's magnitude shows maximum values for polarisation parallel to the nearby ice divide and disappears for polarisation perpendicular to it, identifying the orientation of the girdle to lie in the vertical plane parallel to the ice divide. Observations allow us to extrapolate the crystal orientation feature along the reflector in space, with implications for ice-sheet dynamics and modeling.

Parabolic trough or dish reflector for use in concentrating solar power apparatus and method of making same

Abstract: A reflector (e.g., mirror) for use in a solar collector or the like is provided. In certain example embodiments of this invention, a reflector is made by (a) forming a reflective coating on a thin substantially flat glass substrate (the thin glass substrate may or may not be pre-bent prior to the coating being applied thereto), (b) optionally, if the glass substrate in (a) was not prebent, then cold-bending the glass substrate with the reflective coating thereon; and (c) applying a plate or frame member to the thin bent glass substrate with the coating thereon from (a) and/or (b), the plate or frame member (which may be another thicker pre-bent glass sheet, for example) for maintaining the thin glass substrate and coating thereon in a desired bent orientation in a final product which may be used as parabolic trough or dish type reflector in a concentrating solar power apparatus or the like.

Prosthesis Deployment Apparatus and Methods

Abstract: The position of a prosthesis (e.g., a stent-graft) is monitored using non-ionizing energy during deployment and/or sheath pull-back after the prosthesis has been positioned at a desired location in a vessel, i.e. using a sensor like an electromagnetic sensing coil, an optical LED, a radio frequency beacon, a pressure wave beacon, an optical reflector, an ultrasound beacon.

Near-Field Radio Holography of Large Reflector Antennas

Abstract: We summarise the mathematical foundation of the holographic method of measuring the reflector profile of an antenna or radio telescope. In particular, we treat the case, where the signal source is located at a finite distance from the antenna under test, necessitating the inclusion of the so-called Fresnel field terms in the radiation integrals. We assume a ``full phase'' system with reference receiver to provide the reference phase. We describe in some detail the hardware and software implementation of the system used for the holographic measurement of the 12m ALMA prototype submillimeter antennas. We include a description of the practicalities of a measurement and surface setting. The results for both the VertexRSI and AEC (Alcatel-EIE-Consortium) prototype ALMA antennas are presented.

EBG Enhanced Feeds for the Improvement of the Aperture Efficiency of Reflector Antennas

Abstract: We describe the use of electromagnetic bandgap (EBG) super-layers to improve the shape of reflectors illumination function. Following an investigation of the leaky wave pole singularities of the EBG Green's function, the shape of the radiation patterns of small apertures in ground planes are optimized. The maximization of the reflector aperture efficiency can be obtained by properly tuning the super layers geometrical parameters. A prototype of such feed has been designed, manufactured and tested. The results indicate that the inclusion of the EBG, increases the aperture efficiency of the feed+reflector system to values higher than 80%, over a 10% bandwidth. These low profile feeds are compatible with printed circuit board and/or integrated technology.

Tracking method and measuring system comprising a laser tracker

Abstract: Disclosed is a measuring system comprising a laser tracker (10), a target point marked by a reflector (12), a surveying apparatus (13), and an arithmetic and control unit (14). The laser tracker emits a measuring beam (M) which is reflected by the reflector, a process that is used for determining the distance between the laser tracker (10) and the reflector (12). The surveying apparatus has a known position and orientation relative to the measuring beam (M) while preferably being embodied as a survey camera. The inventive measuring system is designed so as to track the reflector (12) via the measuring beam (M). In a normal tracking mode (A), a measured value for controlling the orientation of the measuring beam (M) is derived from the detection of the measuring beam reflected by the reflector (12). If the measuring beam is not directed onto the reflector, i.e. the measuring beam (M) is not reflected by the reflector and thus no reflected measuring beam can be detected by the laser tracker, the system switches to a special tracking mode in which the measured value for controlling the orientation of the measuring beam (M) is derived from an image (20) of the survey camera (13).

Modulating the intensity of light from an interferometric reflector

Abstract: An optical device for modulating the intensity of light from an interferometric reflector. In one embodiment, the optical device can include an optical stack having a reflective layer and a partially reflective, partially transmissive layer for reflecting light. The optical device can also include a fluid cell comprising an absorptive fluid and a transmissive fluid. The optical device can also include a mechanism for controlling the portion of the reflector which is shadowed by the absorptive fluid.

Near-Field Radio Holography of Large Reflector Antennas

Abstract: We summarize the mathematical foundation of the holographic method of measuring the reflector profile of an antenna or radio telescope. In particular, we treat the case where the signal source is located at a finite distance from the antenna under test, necessitating the inclusion of the so-called Fresnel field terms in the radiation integrals. We assume a "full phase" system with reference receiver to provide the reference phase. We describe in some detail the hardware and software implementation of the system used for the holographic measurement of the 12 m ALMA prototype sub-millimeter antennas. We include a description of the practicalities of a measurement and surface setting. The results for both the VertexRSI and AEC (Alcatel-EIE-Consortium) prototype ALMA antennas are presented.

Led assembly for rear lamps in an automobile

Abstract: Various techniques are described herein for combining two or more LEDs in a single reflective cavity for a rear lamp in an automobile. The LEDs may be two or more different colors for performing different functions, such as a stop light, a turn signal, and a tail light. In one embodiment, the LEDs have side emitting lenses and are coaxially aligned in a parabolic reflector. The LEDs may be mounted facing each other or mounted in the same direction, or a combination of both. The LEDs may share a common heat sink. A second reflector may be positioned inside a larger reflector, where a first LED is mounted near the focal point of the larger reflector, and a second LED is mounted near the focal point of the inner reflector. Additional LEDs may also be mounted in either reflector and separately controlled.

Vertical-cavity, surface-emission type laser diode and fabrication process thereof

Abstract: A vertical-cavity, surface-emission-type laser diode includes an optical cavity formed of an active region sandwiched by upper and lower reflectors, wherein the lower reflector is formed of a distributed Bragg reflector and a non-optical recombination elimination layer is provided between an active layer in the active region and the lower reflector.

Focal waveform of a prolate‐spheroidal impulse‐radiating antenna

Abstract: [1] This paper develops some analytical approximations for the transient focal waveform produced at the second focus of a prolate-spheroidal reflector due to a pulse TEM wave launched from the first focus. This is extended to consider the spot size of the peak field near the second focus.

High-Performance GaN-Based Vertical-Injection Light-Emitting Diodes With TiO $_{2}$ –SiO $_{2}$ Omnidirectional Reflector and n-GaN Roughness

Abstract: We have designed and fabricated a new type of GaN-based thin-film vertical-injection light-emitting diode (LED) with TiO2-SiO 2 omnidirectional reflector (ODR) and n-GaN roughness. The associated ODR designed for LED operation wavelength at 455 nm was integrated with patterned conducting channels for the purpose of vertical current spreading. With the help of laser lift-off and photo-electrochemical etching technologies, at a driving current of 350 mA and with chip size of 1 mm times 1 mm, the light-output power and the external quantum efficiency of our thin-film LED with TiO2-SiO2 ODR reached 330 mW and 26.7%. The result demonstrated 18% power enhancement when compared with the results from the thin-film LED with Al reflector replace

Numerical Analysis of Quasioptical Multireflector Antennas in 2-D With the Method of Discrete Singularities: E-Wave Case

Abstract: Numerical method for modeling the E-polarized wave scattering by electrically large quasioptical two-dimensional (2-D) reflectors is presented. Reflectors are assumed zero-thickness and perfectly electrically conducting. Efficient numerical solution is obtained from the coupled singular integral equations discretized using new quadrature formulas of interpolation type. It has controlled accuracy and deals with small-size matrices. To simulate a small-horn feeding, the incident field is taken as a beam generated by a complex-source-point (CSP) current. Presented numerical results validate empirical rule of -10 dB edge illumination needed to provide the best electromagnetic performance of reflector

White interferometric modulators and methods for forming the same

Abstract: An iterferometric modulator array is configured to reflect a broad band spectrum of optical wavelengths by arranging a reflector and a partially transparent substrate in a non-parallel relationship.

New insights into the P- and S-wave velocity structure of the D″ discontinuity beneath the Cocos plate

Abstract: SUMMARY Broad-band P- and S-waves from earthquakes in South America recorded at Californian network stations are analysed to image lateral variations of the D �� -discontinuity beneath the Cocos plate. We apply two array processing methods to the data set: a simplified migration method to the P-wave data set and a double-array method to both the P- and S-wave data sets, allowing us to compare results from the two methods. The double-array method images a dipping reflector at a depth range from 2650 to 2700 km in the southern part of the study area. We observe a step-like topography of 100 km to a shallower reflector at about 2600 km depth to the north, as well as evidence for a second (deeper) reflector at a depth range from 2700 to 2750 km in the north. Results from the simplified migration agree well with those from the double-array method, similarly locating a large step in reflector depth in a similar location (about 2650 km depth in the south and about 2550 km in the north) as well as the additional deeper reflector at the depth of about 2750 km in the north. Waveform modelling of the reflected waves from both methods suggests a positive velocity contrast for S waves, but a negative velocity contrast for P waves for the upper reflector in agreement with predictions from mineral physical calculations for a post-perovskite phase transition. The data also show some evidence for the existence of another deeper reflector that could indicate a double intersection of the geotherm with the post-perovskite stability field, that is, the back-transformation of post-perovskite to perovskite close to the core‐mantle boundary.

Heat-dissipating resin composition, substrate for led mounting, reflector, and substrate for led mounting having reflector portion

Abstract: The objective of the present invention is to provide a heat-dissipating resin composition that is used for forming a substrate for LED mounting or a reflector provided on the substrate for LED mounting and is excellent in heat dissipation, electrical insulation, heat resistance and light resistance while an LED element emits light, a substrate for LED mounting and a reflector comprising the composition. The present composition comprises a thermoplastic resin such as modified PBT and a thermally conductive filler consisting of scaly boron nitride or the like, and has thermal deformation temperature of 120° C. or higher, a thermal conductivity of 2.0 W/(m·K) or higher, and a thermal emissivity of 0.7 or higher.

Projection Matrix Method for Shaped Beam Synthesis in Phased Arrays and Reflectors

Abstract: We present the projection matrix method for shaped beam synthesis in a general array of different size elements. The method relies on orthogonal projection of the desired far-field intensity vector onto the space spanned by the far-field intensity vectors of the array elements. It is found that for a uniform convergence of the solution, the far-field sample space must be extended beyond the coverage region; otherwise the projection matrix becomes ill conditioned. A general guideline for the far-field sample space is provided. The method, with necessary amendments, is then employed successfully for a reflector surface synthesis. The method is found to be several times faster than the gradient search method commonly used for beam synthesis. Numerical results for array and shaped reflector syntheses are shown and the advantages discussed

Prospects of Large Deployable Reflector Antennas for a New Generation of Geostationary Doppler Weather Radar Satellites

Abstract: A novel mission concept, namely NEXRAD in Space, has been developed for detailed monitoring of hurricanes, cyclones, and severe storms from a geostationary orbit. This mission concept requires a space deployable 35-m diameter reflector that operates at 35GHz with a surface figure accuracy requirement of 0.21 mm RMS. This reflector is well beyond the current state-of-the-art. To implement this mission concept, several potential technologies associated with large, lightweight, spaceborne reflectors have been investigated by this study. These spaceborne reflector technologies include mesh reflector technology, inflatable membrane reflector technology and Shape Memory Polymer reflector technology.

Early kick detection in an oil and gas well

Abstract: A stepped reflector on the outside of a bottomhole assembly produces two reflections in response to excitation of a transducer. The velocity of the fluid in the borehole is estimated using the two reflections. Alternatively, a change in the gas content of the borehole fluid is estimated from changes in the electrical impedance of a transducer in contact with the borehole fluid.

Beam switching antenna system and method and apparatus for controlling the same

Abstract: A beam switching antenna method and apparatus for controlling a beam switching antenna system including an antenna element for forming a beam, at least one conductive reflector for reflecting the beam, and a ground switch for applying a reference voltage to the at least one conductive reflector, the method includes forming the beam of the antenna element, and imparting the formed beam with a predetermined beam pattern by controlling the ground switch to apply the reference voltage to at least one conductive reflector