Showing papers on "Reflector (antenna) published in 2008"

Demonstration of enhanced absorption in thin film Si solar cells with textured photonic crystal back reflector

Abstract: Herein the authors report the experimental application of a powerful light trapping scheme, the textured photonic crystal (TPC) backside reflector, to thin film Si solar cells. TPC combines a one-dimensional photonic crystal as a distributed Bragg reflector with a diffraction grating. Light absorption is strongly enhanced by high reflectivity and large angle diffraction, as designed with scattering matrix analysis. 5 μm thick monocrystalline thin film Si solar cells integrated with TPC were fabricated through an active layer transfer technique. Measured short circuit current density Jsc was increased by 19%, compared to a theoretical prediction of 28%.

Integrated millimeter wave antenna and transceiver on a substrate

Abstract: A semiconductor chip integrating a transceiver, an antenna, and a receiver is provided. The transceiver is located on a front side of a semiconductor substrate. A through substrate via provides electrical connection between the transceiver and the receiver located on a backside of the semiconductor substrate. The antenna connected to the transceiver is located in a dielectric layer located on the front side of the substrate. The separation between the reflector plate and the antenna is about the quarter wavelength of millimeter waves, which enhances radiation efficiency of the antenna. An array of through substrate dielectric vias may be employed to reduce the effective dielectric constant of the material between the antenna and the reflector plate, thereby reducing the wavelength of the millimeter wave and enhance the radiation efficiency. A design structure for designing, manufacturing, or testing a design for such a semiconductor chip is also provided.

Ferroelectric all-polymer hollow bragg fibers for terahertz guidance

Abstract: A method for fabricating a terahertz waveguide comprises forming a multilayer reflector formed of alternating layers of first and second polymer materials with distinct refractive indices, and defining with the multilayer reflector a hollow core through which terahertz radiation propagates. The corresponding terahertz waveguide comprises the multilayer reflector formed of the alternating layers of the first and second polymer materials with distinct refractive indices, and a hollow core defined by the multilayer reflector and through which terahertz radiation propagates.

Light emitting diode recessed light fixture

Abstract: A recessed light fixture includes an LED module, which includes a single LED package that is configured to generate all light emitted by the recessed light fixture. For example, the LED package can include multiple LEDs mounted to a common substrate. The LED package can be coupled to a heat sink for dissipating heat from the LEDs. The heat sink can include a core member from which fins extend. Each fin can include one or more straight and/or curved portions. A reflector housing may be coupled to the heat sink and configured to receive a reflector. The reflector can have any geometry, such as a bell-shaped geometry including two radii of curvature that join together at an inflection point. An optic coupler can be coupled to the reflector housing and configured to cover electrical connections at the substrate and to guide light emitted by the LED package.

Optical management in high-efficiency thin-film silicon micromorph solar cells with a silicon oxide based intermediate reflector

Abstract: Note: IMT-NE Number: 488 Reference PV-LAB-ARTICLE-2008-002doi:10.1002/pssr.200802118 Record created on 2009-02-10, modified on 2017-05-10

System and method for filling level determination

Abstract: A method for determining a filling level of a product contained in a tank, by means of a radar level gauge system comprising a transceiver for generating, transmitting and receiving electromagnetic signals; a probe connected to the transceiver and arranged to guide a transmitted electromagnetic signal from the transceiver towards and into the product inside the tank, and to return a reflected electromagnetic signal resulting from reflection of the transmitted electromagnetic signal by a surface of the product back towards the transceiver; and a plurality of reference reflectors each being arranged at a respective known position along the probe and being configured to reflect a portion of the transmitted electromagnetic signal back towards the transceiver. The method comprises the steps of identifying, based on received electromagnetic signals reflected by the reference reflectors, a set of reference reflectors located above the surface of the product; selecting first and second reference reflectors comprised in the set of reference reflectors; determining a propagation velocity compensation factor based on a known distance between the first and second reference reflectors and a distance therebetween determined using received electromagnetic signals reflected by the first and second reference reflector, respectively; and determining the filling level based on a received electromagnetic signal reflected by the surface of the product, and the propagation velocity compensation factor.

Ultraviolet reflector with coolant gas holes and method

Abstract: A reflector for an ultraviolet lamp can be used in a substrate processing apparatus. The reflector comprises a longitudinal strip extending the length of the ultraviolet lamp. The longitudinal strip has a curved reflective surface and comprises a plurality of through holes to direct a coolant gas toward the ultraviolet lamp. A chamber that uses an ultraviolet lamp module with the reflector, and a method of ultraviolet treatment are also described.

Rear-loaded light emitting diode module for automotive rear combination lamps

Abstract: A rear-loading LED module for a rear combination lamp is disclosed. One or more LEDs are mounted on a printed circuit board that mechanically holds them at the focus of a faceted, parabolic reflector. Light from the LEDs diverges transversely and horizontally, and is collimated by the reflector, and the reflected collimated light is directed in a generally longitudinal direction out of the rear combination lamp, toward the viewer. The LED module itself is generally longitudinally oriented, and is insertable longitudinally into the interior of the reflector from a hole at the vertex of the reflector. The printed circuit board, an optional thermal pad adjacent to the printed circuit board, and a thermally conductive layer adjacent to the optional thermal pad are all generally planar layers, are all generally parallel to each other, and may optionally all have the same footprint. Together, the printed circuit board, the thermal pad and the thermally conductive layer may all form a generally planar ledge.

A multigigawatt X-Band relativistic backward wave oscillator with a modulating resonant reflector

Abstract: Effective generation regime with a high output pulse power has been experimentally realized in a relativistic backward wave oscillator (RBWO) with a resonant reflector and a slow-wave system having a diameter 1.6 times the radiation wavelength. At a guiding magnetic field of 4.5 T, the maximum peak power amounted to 4.3 GW at a frequency of 9.4 GHz, an efficiency of 31%, and a microwave pulse duration of 22 ns.

Back reflector for use in photovoltaic device

Abstract: This invention relates to a photovoltaic device including a back reflector. In certain example embodiments, the back reflector includes a metallic based reflective layer provided on an interior surface of a rear glass substrate of the photovoltaic device. In certain example embodiments, the interior surface of the rear glass substrate is textured so that the reflector layer deposited thereon is also textured so as to provide desirable reflective characteristics. The rear glass substrate and reflector thereon are laminated to the interior surface of a front glass substrate of the photovoltaic device, with an active semiconductor film and electrode(s) therebetween, in certain example embodiments.

Continuous and simultaneous measurement of reflector depth and average soil-water content with multichannel ground-penetrating radar

Abstract: Ground-penetrating radar is a fast noninvasive technique that can monitor subsurface structure and water-content distribution. To interpret traveltime information from single common-offset measurements, additional assumptions, such as constant permittivity, usually are required. We present a fast ground-penetrating-radar measurement technique using a multiple transmitter-and-receiver setup to measure simultaneously the reflector depth and average soil-water content. It can be considered a moving minicommon-midpoint measurement. For a simple analysis, we use a straightforward evaluation procedure that includes two traveltimes to the same reflector, obtained from different antenna separations. For a more accurate approach, an inverse evaluation procedure is added, using traveltimes obtained from all antenna separations at one position and its neighboring measurement locations. The evaluation of a synthetic data set with a lateral variability in reflector depth and an experimental example with a large variability in soil-water content are introduced to demonstrate the applicability for field-scale measurements. The crucial point for this application is the access to absolute traveltimes, which are difficult to determine accurately from common-offset measurements.

Wideband Cavity-Backed Bowtie Antenna With Pattern Improvement

Abstract: A wide-band unidirectional cavity-backed bowtie antenna with stable radiation patterns is proposed in this paper. It is differentially fed by a parallel strip line via a transition from a microstrip line. The corners of the conventional triangular bowtie dipole are rounded to achieve a larger impedance bandwidth. A circular ring, acting as a special reflector, is placed within the cavity, between the ground plane and the bowtie dipole, for stabilizing the broadside radiation patterns over the whole operating band. Numerical simulations and parametric studies are performed to verify the effectiveness of the ring reflector for radiation pattern improvement when it is electrically close to the bowtie dipole. The final design is fabricated and measured. Measured results indicate that the proposed antenna features an impedance bandwidth of 91.4% for SWR les 2, a 7.3-9.5 dBi broadside gain, a total size of 1.56 times 0.325lambda0 2 (lambda0 is the free-space wavelength at the center frequency) and stable radiation patterns over the whole band.

Dual trough concentrating solar photovoltaic module

Abstract: A photovoltaic solar energy collector suitable for use in a solar energy collection system that tracks movements of the sun along at least one axis. The collector may have an aperture and having at least one reflector panel, at least one solar receiver, each solar receiver including a plurality of photovoltaic cells having cell faces that are oriented substantially perpendicular to the collector aperture, and a support structure that supports the at least one reflector panel.

Design of High Efficiency Circular Horn Feeds for Multibeam Reflector Applications

Abstract: Design aspects of high efficiency profiled circular horns with thin walls as feeds for multibeam reflector antennas for satellite applications are presented in this paper. The modal content at the circular aperture of the horn necessary to closely approximate a unipolarized uniform distribution is first established. Slope discontinuities along the length of the horn are then used to generate the necessary aperture modes with the appropriate amplitudes and phases. The performance of the horn is calculated using the mode matching technique. Significant improvement in the horn aperture efficiency and reduction in the cross-polar level over a straight conical horn can be achieved over a single band or two bands that are widely separated in frequency. This conclusion is supported by the good agreement between predictions and measurements of a high efficiency dual-band horn.

Investigation of an oversized backward wave oscillator as a high power microwave generator

Abstract: An oversized rectangular corrugated backward wave oscillator is designed and theoretically analyzed to produce TM01 high power microwave radiation in the frequency of 868GHz without mode competition The device includes a slow wave structures, a resonant reflector, and an output waveguide The slow wave structure and the reflector are matched to achieve mode selection and enhance interaction efficiency Feedback processes from the reflector are introduced to explore mode selection in the configuration In particle in cell simulation, high power microwaves of TM01 mode are generated with peak power of 20GW, frequency of 868GHz, and conversion efficiency is 286% when beam voltage is 500kV and current 14kA

Leaky wave enhanced feed arrays for the improvement of the edge of coverage gain in multibeam reflector antennas

Abstract: The performance of multibeam focal plane arrays feeding a single aperture is usually reduced due to conflicting requirements on the feed elements. Dense packing is usually required to minimize the beam separation, while typically large feed apertures are needed to provide the high feed directivity to reduce spillover losses from the reflector. In this paper the use of dielectric super-layers to shape the radiation pattern of each feed is demonstrated. The shaping is obtained by exciting, according to design, a pair of TE/TM leaky waves. The spillover from the reflector is reduced without physically increasing the dimensions of each single element aperture. A prototype of a feed array composed of 19 waveguides arranged in a hexagonal lattice was designed, manufactured and tested. The measured embedded patterns provided an increase of the edge of coverage gain, with respect to the free space case, of at least 0.6 dB in an operating bandwidth (BW) of ap12%. Moreover when reactive loading of adjacent feeds is adopted the increase in the edge of coverage with respect to the free space case was demonstrated to be larger than 1.6 dB over a 3% BW.

Heliostat with integrated image-based tracking controller

Abstract: A system (100) for directing incident sun light to a receiver (150) based on an integral imager (116) is disclosed. The system includes an imager (116) mounted to a reflector (112); a tracking controller (226) coupled to the imager; and one or more actuators (114) connected to the reflector and tracking controller. The tracking controller (226) is configured to receive and process image data from the imager (116); determine angular positions of a radiation source and target relative to the mirror normal vector (N) based on the image data; and orient the reflector with the axis bisecting the angular positions of the sun and receiver (150). When the optical axis of the imager is precisely aligned with the vector normal to the reflector, the source and target will be detected as antipodal spots (320, 330) with respect to the center of the imager's field of view, which may be used to effectively track the sun or like object.

Leaky-Wave Slot Array Antenna Fed by a Dual Reflector System

Abstract: A leaky-wave slot array antenna fed by a dual offset Gregorian reflector system is realized by pins in a parallel plate waveguide. The radiating part of the antenna is composed by parallel slots etched on one side of the same parallel plate waveguide. The dual offset Gregorian reflector system is fed by an arrangement constituted by two vias and a grid, also constituted by pins. Also this feed arrangement realizes a leaky type of radiation, this time inside the parallel plate waveguide. A prototype of the antenna has been designed, manufactured and successfully tested. The low profile, low cost and high efficiency of the antenna render it suited for a variety of radar or telecom applications.

Medical device including scanned beam unit for imaging and therapy

Abstract: A medical device includes a radiation source assembly having at least two radiation sources, where one or more of the radiation sources is adapted to generate an imaging beam for use in visualization of a scene and one or more of the radiation sources is adapted to generate a therapeutic beam for treatment of a medical condition. An optical fiber for directing radiation energy from the radiation source assembly toward a distal end of the medical device in the form of a beam. A reflector that receives the beam from the optical fiber, the reflector configured to direct the beam onto a field-of-view. A receiving system including a detector arranged and configured to receive radiation from the field-of-view to generate a viewable image. The imaging beam and the therapeutic beam are directed to follow a common path from the at least two radiation sources to the reflector.

Surface-emitting laser element

Abstract: PROBLEM TO BE SOLVED: To provide a surface-emitting laser element that can achieve high speed modulation, high reliability, and a good transmission characteristic at the same time.SOLUTION: A surface-emitting laser element comprises: a lower multilayer film reflector and an upper multilayer film reflector constructed by a periodic structure of a high refractive index layer and a low refractive index layer, and forming an optical resonator: an active layer formed between the lower multilayer film reflector and the upper multilayer film reflector; and a plurality of current constriction layers formed between the upper multilayer film reflector and the active layer, or within the upper multilayer film reflector, and including a current injection part and a selective oxidation layer formed on the outer periphery of the current injection part by selective oxidation thermal processing. The plurality of current constriction layers each are equal to or less than 60 nm in layer thickness, are formed at places nearly corresponding to nodes of the standing wave of light formed by the optical resonator.

94 GHz Folded Fresnel Reflector Using C-Patch Elements

Abstract: A 94 GHz folded Fresnel reflector (FFR) for helicopter collision avoidance Radar is presented. The antenna system consists of a primary source illuminating a semi-reflecting grid that reflects the primary source polarization toward the main reflector opposite the grid. The main reflector has two functions. It focuses the field in the desired direction and rotates the incident polarization by 90deg to enable it to pass through the grid and radiate. Specific patch elements having a C-shape have been designed for this purpose. In order to increase overall efficiency, the reflector combines 8 correcting zones in its center and 4 at the periphery. The reflector is manufactured using standard photolithographic techniques. The primary source consists of a metal waveguide covered with a small frequency selective surface (FSS) for matching purposes. The maximum measured gain is 36.5 dBi at 94 GHz. The maximum side lobe level is -18 dB. The return loss value does not exceed -25 dB. The frequency bandwidth -3 dB in gain and return loss is 10%. In-flight measurements were conducted demonstrating the ability to detect power lines at distances up to 680 m.

Controlling a ray bundle with a free-form reflector

Abstract: The problem of controlling a single ray bundle with a single reflector is not generally solvable, but approximate solutions may often be found that are acceptable for applications. We introduce a new technique for finding such approximations and apply it to the design of a driver-side mirror for an automobile that has no blind spot and minimal distortion.

Enhanced EBG Resonator Antenna as Feed of a Reflector Antenna in the Ka Band

Abstract: Recent studies have shown that a multibeam reflector antenna could be illuminated by a multifeed electromagnetic bandgap (EBG) structure, in order to achieve a high gain multispot coverage with the simple "one feed by beam" concept and only one aperture. This letter deals with the design of a metallic EBG antenna in the Ka band, feeding a side-fed offset cassegrain antenna (SFOCA) for a European multispot coverage. This reflector presents a high focal-length-to-diameter ratio limiting the defocusing effects for multibeam applications. It, therefore, requires focal feeds with a high directivity and a good radiation pattern quality. The well-known drawbacks of an EBG antenna are the narrow radiation bandwidth for high directivities and also the high sidelobes level reducing the reflector antenna efficiency. Consequently, the work presented in this letter consisted in improving the EBG antenna performances by using a more efficient feed. The replacement of the usual microstrip patch by a horn allowed to double the radiation bandwidth while decreasing the sidelobes level (-15 dB) of a 24-dB EBG antenna. A metallic prototype excited by a single horn has been manufactured at 30 GHz, and the measurements agree with the simulation. This device with one feed allows good SFOCA performances, similar to those obtained with a conventional focal feed like a Potter horn.

System and method for monitoring objects, people, animals or places

Abstract: An improved system and method for monitoring objects, people, animals, or places uses a passive Modulating Reflector (MR) tag where a characteristic of an antenna is modified according to a time-varying pattern by a modulating network thereby causing the reflective characteristics of the antenna to vary in accordance with the time-varying pattern. When an interrogator transmits an RF waveform that impinges on the antenna, the return signal reflecting off the antenna is modulated in accordance with the time-varying pattern allowing a remote receiver to demodulate information from the modulated return signal. The antenna is embedded in a dielectric material. The MR tag can be used with a wide variety of tag-interrogator configurations employing monostatic and/or bistatic radar techniques to allow monitoring, locating, and/or tracking of objects, people, animals, or place with which MR tags are associated.

Automotive radar using a metamaterial lens

Abstract: An example apparatus comprises an electromagnetic source, such as an antenna, a metamaterial lens, and a reflector The antenna is located proximate the metamaterial lens, for example supported by the metamaterial lens, and the antenna is operable to generate radiation when the antenna is energized The reflector is positioned so as to reflect the radiation through the metamaterial lens The reflector may have a generally concave reflective surface, for example having a parabolic or spherical cross-section The metamaterial lens may have an area similar to that of the aperture of the reflector In some examples, the antenna is located proximate a focal point of the reflector, so that a generally parallel beam is obtained after reflection from the reflector

Wireless transceiver within an electrical receptacle system

Abstract: An electrical receptacle assembly having a housing that includes a wireless transceiver electrically coupled to one or more antennas that can be integrated into the receptacle housing itself or in the receptacle's faceplate. The one or more antennas can be one or more dipoles or a single loop antenna. The housing also houses a power converter that derives its power directly from the line connection to the outlet. A junction box includes an integrated antenna reflector for improved radio direction and propagation relative to the antenna(s). Or, an antenna reflector insert is placed within the junction box behind the electrical receptacle assembly. The electrical receptacle assembly further includes a temperature sensor, a PLC module, or a current/voltage sensor and communicates associated data via its wireless transceiver. A status indicator is disposed on the front of the housing. A reset switch on housing resets the electronics to a default state.

High-power relativistic microwave sources based on the backward wave oscillator with a modulating resonant reflector

Abstract: Results of theoretical and experimental investigations into a relativistic backward wave oscillator with a modulating resonant reflector are generalized. The modulating resonant reflector is used to reflect a counter propagating wave and guide it toward an electron collector. It is shown that premodulation of the electron beam near the reflector may have a significant effect on the starting conditions of oscillation; selective properties of the oscillator; and its efficiency, which may reach 40% when a high-current beam is transported by a strong magnetic field. In the reduced magnetic fields that were employed in the pulsed-periodic regime and were 1.5–2.0 times lower than those at which cyclotron resonance with the counter propagating wave is observed, the oscillator efficiency (30–35% at a wavelength of 8 mm) is limited by position and velocity spreads of particles. Mechanical pulsewise frequency tuning within about 10% at a repetition rate of 1–50 Hz and a multigigawatt microwave power, as well as a rise in the power and energy of microwave pulses via an increase in the cross-sectional dimensions of the slow-wave structure, are demonstrated to be feasible.

Image sensor reflector

Abstract: An array of pixels is formed using a substrate, (101) where each pixel has a substrate having an incident side for receiving incident light, (150) a photosensitive region (102, 104, 106) formed in the substrate, and a reflector (140, 142, 144) having a complex-shaped surface. The reflector is formed in a portion of the substrate that is opposed to the incident side such that light (150) incident on the complex- shaped surface of the reflector is reflected towards the photosensitive region.