Showing papers on "Reflector (antenna) published in 2005"

Multi-beam antenna

Abstract: A plurality of antenna elements on a dielectric substrate are adapted to launch or receive electromagnetic waves in or from a direction substantially away from either a convex or concave edge of the dielectric substrate, wherein at least two of the antenna elements operate in different directions. Slotlines of tapered-slot endfire antennas in a first conductive layer of a first side of the dielectric substrate are coupled to microstrip lines of a second conductive layer on the second side of the dielectric substrate. A bi-conical reflector, conformal cylindrical dielectric lens, or discrete lens array improves the H-plane radiation pattern. Dipole or Yagi-Uda antenna elements on the conductive layer of the dielectric substrate can be used in cooperation with associated reflective elements, either alone or in combination with a corner-reflector of conductive plates attached to the conductive layers proximate to the endfire antenna elements.

Multi-function field-deployable resource harnessing apparatus and methods of manufacture

Abstract: A multi-function, field-deployable resource harnessing apparatus having, in its embodiments, an inflatable reflector apparatus comprising at least one manufactured parabolic mirror made from a pressure-deformable reflective covering of an inflatable ring for focusing electromagnetic energy from radio frequency radiation (RF) through the ultraviolet (UV) radiation including solar energy. A first main embodiment of the inflatable reflector apparatus generally utilizes two pressure-deformable membranes, at least one of which is reflective. A second main embodiment utilizes a reflective membrane and a transparent membrane. In addition to the reflector apparatus, the modular apparatus typically further includes modular assemblies to increase versatility facilitate use, and/or enhance safety such as, for example, a modular support and orienting assembly, a separate support ring, a safety shield or cage, a focal point support assembly, a safety cover, a safety net or mesh, and a stabilizing assembly. Portability is enhanced by complete collapsing of the inflatable device.

Optical communication device provided with a reflector and method for forming a reflector in an optical communication device

Abstract: An optical communication device of the invention includes a reflector for reflecting the light that has reached one end surface of a waveguide chip to turn the optical path of the light The reflector includes a transparent thin film layer formed on one end surface of the waveguide chip by using a material to which a metal that forms an intermetallic compound or the like with Au is added to a substance that is transparent to the light that propagates through the waveguide, as well as an Au thin film layer formed on the front surface of the transparent thin film layer This allows formation of a reflector having an Au thin film layer as a reflecting surface in an optical medium with high adhesion strength Thus, an optical communication device can be provided having a high reliability with little loss

Reflector antenna radome with backlobe suppressor ring and method of manufacturing

Abstract: A radome adapted to reduce backlobes of an associated reflector antenna via application of a conductive ring with an inward facing edge about the periphery of the radome. The conductive ring may be applied extending around the radome periphery to an inside and or outside surface of the radome. The conductive ring may be formed upon the radome by metalising, electrodaging, over molding or the like. Further, the conductive ring may be a metal, metallic foil, conductive foam or the like which is coupled to the radome. An absorber in the form of a ring or a surface coating applied to the radome and or the distal end of the reflector may also be added between the radome and the reflector.

Intruder detecting device and radiowave reflector

Abstract: PROBLEM TO BE SOLVED: To provide a reliable intruder detecting device capable of reducing false detection, by enhancing identification accuracy between detecting objects and non-detecting objects. SOLUTION: A transmitting and receiving antenna 1a of the radar 1 is configured with a parabolic antenna, a radiowave reflector 2 is configured with a reflector array 6 consisting of a plurality of reflectors, and the beam widths A1 and A2 of the transmitter wave 5 in the vicinity of the radar 1 and of the reflected wave 7 in the vicinity of the radiowave reflector 2, respectively, are established to be larger than the beam width C the non-detecting objects, such as a bird 9 to be removed from detecting objects, can interrupt. COPYRIGHT: (C)2006,JPO&NCIPI

Planar electromagnetic metamaterial with a fish scale structure.

Abstract: We report on a continuous electromagnetic metal planar metamaterial, which resembles a "fish scale" structure. Apart from the one isolated wavelength, it is highly transparent to electromagnetic radiation throughout a broad spectral range and becomes completely "invisible" at some frequency inflicting no transmission losses and phase delay. When the structure is superimposed on a metallic mirror it becomes a good broadband reflector everywhere apart from one wavelength where the reflectivity is small. At this wavelength the reflected wave shows no phase change with respect to the incident wave, thus resembling a reflection from a hypothetical zero refractive index material, or "magnetic wall." We also discovered that the structure acts as a local field concentrator and a resonant "amplifier" of losses in the underlying dielectric.

Dual-polarized antenna

Abstract: A dual polarized antenna with at least one dual polarized radiator device comprises a reflector (3) and longitudinal or transverse webs (9, 11) provided at least on its longitudinal side and/or on its transverse side. The improvement is distinguished by the following features: at least one longitudinal web (9) and/or at least two longitudinal webs (9) provided with respect to the radiator device (1, 1′) located in between and/or at least one transverse web (11) and/or at least two transverse webs (11) provided with respect to the radiator device (1, 1′) located in between are positionally changeable directly or at least indirectly by pivoting and/or bending and/or deforming and curving.

Multi-band monopole antennas for mobile communications devices

Abstract: Antennas for use in mobile communication devices are disclosed. The antennas disclosed can include a substrate with a base, a top, a front side and a back side; a first conductor can be located on the first side of the antenna substrate; and a second conductor can be located on the second side of the antenna substrate. The conductors can have single or multiple branches. If a conductor is a single branch it can, for example, be a spiral conductor or a conducting plate. If a conductor has multiple branches, each branch can be set up to receive a different frequency band. A conductor with multiple branches can have a linear branch and a space-filling or grid dimension branch. A conducting plate can act as a parasitic reflector plane to tune or partially tune the resonant frequency of another conductor. The first and second conductors can be electrically connected.

Power lamp package

Abstract: Adhesive-free assembly of the substrate and reflector components of a semiconductor die package is achieved by injection molding the reflector onto a surface of the substrate or by molding the reflector separate from the substrate and securing it in place on the substrate through deformation of a portion of the reflector. The reflector may be made reflective either by molding the reflector using a light scattering material or through the addition of a reflective element, such as a piece of foil material that is secured to the reflector. A variety of interchangeable reflective elements having different surface shapes, and thus different light reflecting properties, may be made.

A dual planar reflectarray with synthesized phase and amplitude distribution

Abstract: A quasi-planar reflector arrangement for generating an arbitrary phase and amplitude distribution in the antenna aperture and thus a wide range of far field patterns is presented. A parallel pair of reflectarrays is used. One is implemented as a standard reflectarray using rectangular patches on a microwave substrate with metallized backside. The other reflectarray is provided with a polarizing grid, which acts as a ground plane for one polarization and is transparent for the orthogonal polarization. An offset rectangular feed horn is embedded in the lower reflectarray to illuminate the upper reflector. A design procedure for a linear polarized antenna with a sector beam in the azimuth and a narrow beam width in the elevation is presented and is verified with measurement results.

Apparatus and methods for network interface and spectrum management

Abstract: Apparatus and methods for the management of radio frequency spectrum within a network such as a CATV network. In one aspect of the invention, an improved signal reflector apparatus adapted for use in the network is disclosed, the reflector circuit being designed to strongly reflect signal frequencies at the lower end of the CATV reverse band, and/or above the higher end of the forward band, while simultaneously allowing the rest of the reverse band and the entire forward band to pass freely through the device. This selective filtering of the spectrum allows control signals generated within a premises or private network to be directed (by reflection) to other devices within that network. A blocking element (e.g., amplifier) may also be used to provide control of the transmission and attenuation profile of the reflector apparatus. The passage of power signals such as DC or low frequency AC is also optionally provided.

Radiation emitting apparatus with spatially controllable output energy distributions

Abstract: A laser handpiece is disclosed, including a fiber optic end having a non-cylindrical shape and further including a reflector surrounding a portion of the fiber optic end. The reflector is shaped to direct laser energy emitted from the fiber optic end in a direction away from the laser handpiece and toward a treatment site.

Optical interconnect modules with fully integrated reflector mirrors

Abstract: A robust and cost-effective technology for integration of 45/spl deg/ reflector mirrors and polymer waveguides (WGs) into optical interconnect (OI) substrates is developed. The planar WGs are formed from photopatternable polymers with propagation losses as low as 0.05 dB/cm. The mirrors with losses of 0.5-0.8 dB are fabricated by the microdicing technique allowing lateral and vertical positioning of the mirror plane within several microns. A prototype OI module with integrated channel WGs, mirrors, and assembled connectors is fabricated and successfully tested at 10-Gb/s transmission rate.

Advanced precipitation Radar antenna: array-fed offset membrane cylindrical reflector antenna

Abstract: As part of the overall NASA earth science technology research effort, a half-size prototype model of light-weight, dual-frequency and wide-swath scanning antenna for the next generation of spaceborne precipitation radar has recently been developed. It operates radar channels at both 13.6 and 35 GHz for improved rainfall retrieval accuracy. The antenna for proposed spaceborne precipitation radar is an offset parabolic cylindrical reflector fed by two linear arrays. This design is adopted, instead of a double-curved offset reflector, because it provides the required wide scan angle in the cross-track plane at both the Ku and Ka band operating frequencies. To demonstrate the technological readiness of the concept, the focus is on a half-scale model of 2.65 m operating at Ku and Ka band. In this paper, the technology development status on this Advanced Precipitation Radar Antenna will be presented. Design and characterization of the 2.65 m antenna is detailed by presenting the features of various components of the antenna, including simulation of the performance, 2/spl times/166 Ku and 4/spl times/166 Ka element feed array designs and evaluation and the design concept of the membrane reflector. Measurement results of the entire antenna system using a compact range facility will also be summarized.

Effects on the radiation characteristics of using a corrugated reflector with a helical antenna and an electromagnetic band-gap reflector with a spiral antenna

Abstract: An axial-mode helical antenna backed by a perfect electric conductor (PEC reflector) is optimized to radiate a circularly polarized (CP) wave, using the finite-difference time-domain method (FDTDM). After the optimization, the PEC reflector is replaced with a corrugated reflector. The effects of the corrugated reflector on the current distribution along the helical arm and the radiation pattern are investigated. A reduction in the backward radiation is attributed to the reduction in the current flowing over the rear surface of the corrugated reflector. A spiral antenna backed by a PEC reflector of finite extent is also analyzed using the FDTDM. As the antenna height decreases, the reverse current toward the feed point increases, resulting in deterioration of the axial ratio. To overcome this deterioration, the PEC reflector is replaced with an electromagnetic band-gap (EBG) reflector composed of mushroom-like elements. Analysis reveals that the spiral radiates a CP wave even when the spiral is located close to the reflector (0.06 wavelength above the EBG surface). The input impedance for the EBG reflector is more stable over a wide frequency band than that for the PEC reflector.

Characterization of effects of periodic and aperiodic surface distortions on membrane reflector antennas

Abstract: The focus of this paper is to characterize the effects of periodic and aperiodic surface distortions on the performance of membrane reflector antennas. Since the surface of this class of reflector antennas is very thin, it is susceptible to various types of periodic and aperiodic distortions. The particular antenna dimensions used for this study are similar to the specifications for the JPL/UCLA half scale model of second generation precipitation radar (PR-2) mission reflector. Analytical expressions are introduced to model periodic and aperiodic surfaces and based on these models the effects of distortions on the radiation performance of the antenna are simulated. Aperiodic distortions are more realistic cases of distortions due to the fact that the period of the distortions is not constant through out the reflector surface. For each case, far-field patterns of the reflector are simulated and it is shown that closed-form expressions can then be derived which result in a very efficient computational method to predict some of the unique features of these patterns including location and level of observed grating lobes. Furthermore, based on spatial Fourier analysis of the surface distortion, it is shown that deviation from periodicity in the distortions of reflector surface results in lowering these grating lobes. Parametric studies have been performed to provide design guidelines for acceptable surface behavior for large deployable membrane reflector antennas for future space borne missions.

Imaging and suppressing near-receiver scattered surface waves

Abstract: When traveling through a complex overburden, upcoming seismic body waves can be disturbed by scattering from local heterogeneities. Currently, surface-consistent static and amplitude corrections correct for rapid variations in arrival times and amplitudes of a reflector, but these methods impose strong assumptions on the near-surface model. Observations on synthetic and laboratory experiments of near-surface scattering with densely sampled data suggest that removing noise from near-receiver scattering requires multichannel approaches rather than single-channel, near-surface corrections. In this paper we develop a wavefield-based imaging method to suppress surface waves scattered directly beneath the receivers. Using an integral-equation formulation, we account for near-surface heterogeneities by a surface impedance function. This impedance function is used to model scattered surface waves, excited by upcoming wavefronts. The final step in our algorithm is to subtract the scattered surface waves. We succes...

Compact microring-based wavelength-selective inline optical reflector

Abstract: We present a novel design for a compact planar integrated optic reflector based on a microring resonator add-drop wavelength-selective filter. Good agreement is found between the theoretical expectation and the measurements of a device fabricated in optical polymer. The measured device exhibits better than 10-dB rejection for wavelengths resonant with the microring.

Light emitting diodes including barrier layers/sublayers

Abstract: Semiconductor light emitting devices, such as light emitting diodes, include a substrate, an epitaxial region on the substrate that includes a light emitting region such as a light emitting diode region, and a multilayer conductive stack including a reflector layer, on the epitaxial region. A barrier layer is provided on the reflector layer and extending on a sidewall of the reflector layer. The multilayer conductive stack can also include an ohmic layer between the reflector and the epitaxial region. The barrier layer further extends on a sidewall of the ohmic layer. The barrier layer can also extend onto the epitaxial region outside the multilayer conductive stack. The barrier layer can be fabricated as a series of alternating first and second sublayers.

Device and method for wavelength filtering

Abstract: Embodiments include devices and methods for wavelength filtering. For example, one embodiment includes a display comprising a plurality of the display elements each comprising a movable reflector, a first partial reflector, and a second partial reflector. The first partial reflector is positioned at a first distance from the movable reflector and forms a first optical resonant cavity therebetween. The second partial reflector is positioned at a second distance from said first partial reflector and forming a second optical resonant cavity therebetween. In various embodiments, the movable reflector is movable with respect to the first partial reflector to alter the first optical cavity. Other embodiments include a method of making devices.

A uni-directional ring-slot antenna achieved by using an electromagnetic band-gap surface

Abstract: Slot antennas offer a number of advantages including low-profile, ease of fabrication, and ease of integration with electronics. Their main drawback, however, is that they are inherently bi-directional radiators. One common technique to redirect the back radiation forward is to place a conducting reflector at a fixed distance away from the antenna. This distance is usually chosen to be a quarter wavelength so that the reflected back radiation incurs an additional phase of 360/spl deg/ and thus adds in phase with the forward directed radiation. However, in this case the parallel-plate geometry permits the excitation of the dominant transverse electromagnetic mode, which drastically reduces the overall radiation efficiency. This work describes a solution to this problem and shows how to achieve uni-directional slot antenna elements by backing them with an electromagnetic band-gap surface, instead of the uniform conducting reflector. This structure, when operated in its band-gap, inhibits the propagation of electromagnetic waves over all possible azimuthal directions, in the region between the antenna ground plane and the periodic surface.

Optical interference pixel display

Abstract: An electronic device of an embodiment of the invention is for at least partially displaying a pixel of a displayable image. The electronic device includes a first reflector and a second reflector that define an optical cavity therebetween, and which is selective of a visible wavelength at an intensity by optical interference. The electronic device also includes a mechanism to allow optical properties of the optical cavity to be varied. The visible wavelength and/or the intensity are thus variably selectable in correspondence with the pixel of the displayable image.

ICARA: induced-current analysis of reflector antennas

Abstract: The aim of this work is to present the ICARA (induced-current analysis of reflector antennas) software, which is able to predict the behavior of reflector antennas using the physical optics method. The software offers different options for antenna configurations, single and array feed models, and far-field or aperture-field analysis.

Migration-proof light-emitting semiconductor device and method of fabrication

Abstract: An LED has a light-generating semiconductor region formed on an electroconductive baseplate via a reflector layer of silver or silver-base alloy. The light-generating semiconductor region has an active layer between claddings of opposite conductivity types. An anti-migration sheath envelopes either or both of the reflector layer and light-generating semiconductor region in order to prevent the reflector metal from migrating onto the semiconductor region with the consequent possible short-circuiting of the claddings of the active layer.

Flip-chip light-emitting device with micro-reflector

Abstract: A Flip-chip light-emitting device with integral micro-reflector. The flip-chip light-emitting device emits reflected light provided by a light-emitting layer. The micro-reflector reflects light that might otherwise be lost to internal refraction and absorption, so as to increase light-emitting efficiency.

Design and fabrication of omnidirectional reflectors in the visible range

Abstract: An omnidirectional reflector operating in the visible range with the centre wavelength around 532 nm is designed and fabricated. By the calculations of electrical field intensity distributions of the incident light along the propagation direction in the photonic crystal (PC) structure, a minimum period number for producing one-dimensional PCs with an omnidirectional photonic band gap (PBG) is determined. A 12-layer-pair stack of TiO2/SiO2 was grown by the electron-gun evaporation method. Transmission spectra measured with transverse-magnetic- and transverse-electric-polarized incident lights at various angles show that an omnidirectional PBG of 24 nm width is obtained, which is in agreement with theoretically simulated results. This kind of reflector may find applications in engineering measurements, laser beam security, optical filters, biosensors and so on.

Design and measurement of new reflectarray antenna using microstrip patches loaded with slot

Abstract: An array of microstrip patches loaded with slots is used to realise a passive reflectarray antenna in Ku band. The progressive phase distribution on the reflector surface is achieved by controlling both the length of the patch and of the slot aperture. A 437-element array prototype has been measured showing good results over a 4% bandwidth.

Photogrammetric measurement of the gravity deformation in a Cassegrain antenna

Abstract: Photogrammetric measurement of the gravity deformation in a 22-m Cassegrain antenna of the Australia Telescope Compact Array is described. The deformation in the main reflector surface and displacements of the quadripod structure, subreflector, and feed were surveyed at a set of antenna elevations. The elevation dependance of the antenna radiation pattern, calculated from the deformations and displacements, are in good agreement with measurements. This experience is another novel demonstration of the usefulness of photogrammetry in antenna metrology: as a tool for measurements of the gravity-induced structural deformation in reflector surfaces and of the displacements and rotations in optics elements of large steerable antennas.

Apparatus for redirecting parallel rays using rigid translation

Abstract: An accurate and cost effective heliostat array and method of use is disclosed. The heliostat array in the preferred embodiment comprises a plurality of mirrors arrayed in a common plane, a plurality of reflector positioning arms, and a rigid positioning plate. The positioning plate, which is coupled to each of the reflectors via a positioning arm, is adapted to simultaneously aim each reflector using as few as one or two actuators. When the positioning arms forms the base of an isosceles triangle with one leg aligned with a ray directed to the sun and the other equal length leg aligned with a ray directed to the receiver, the positioning plate has the shape of a Conchoid of Nicomedes surface of revolution, which enables the heliostat array to simultaneously orient all of the mirrors to precisely focus incident sunlight from anywhere in the celestial hemisphere onto a common focal point.

Omni-directional reflector and light emitting diode adopting the same

Abstract: Provided are an omni-directional reflector having a transparent conductive low-index layer formed of conductive nanorods and a light emitting diode adopting the omni-directional reflector The omni-directional reflector includes: a transparent conductive low-index layer formed of conductive nanorods; and a reflective layer formed of a metal