Parabolic reflector

About: Parabolic reflector is a research topic. Over the lifetime, 3375 publications have been published within this topic receiving 30735 citations. The topic is also known as: paraboloid reflector & paraboloidal reflector.

Fast and Accurate Analysis of Reflector Antennas With Phased Array Feeds Including Multiple Reflections Between Feed and Reflector

Abstract: Several electrically large phased array feed (PAF) reflector systems are modeled to examine the mechanism of multiple reflections between parabolic reflectors and low-and high-scattering feeds giving rise to frequency-dependent patterns and impedance ripples. The PAF current is expanded in physics-based macro domain basis functions (CBFs), while the reflector employs the physical optics (POs) equivalent current. The reflector-feed coupling is systematically accounted for through a multiscattering Jacobi approach. An FFT expands the reflector radiated field in only a few plane waves, and the reflector PO current is computed rapidly through a near-field interpolation technique. The FEKO software is used for several cross validations, and the convergence properties of the hybrid method are studied for several representative examples showing excellent numerical performance. The measured and simulated results for a 121-element Vivaldi PAF, which is installed on the Westerbork Synthesis Radio Telescope, are in very good agreement.

Etendue efficient coupling of light using dual paraboloid reflectors for projection displays

Abstract: With the introduction of Digital Micromirror Device (DMD) and Liquid Crystal on Silicon (LCOS) technologies, imagers for projection displays become increasingly smaller, thus requiring more intense, focused light with lower etendue values. To illuminate these smaller imagers, a patented dual paraboloid reflector system has been developed to collect and focus light from an arc lamp onto the imager without loss of brightness. This powerful optical platform provides the control and etendue efficiency that has been missing in standard illumination sy stems. The dual paraboloid reflector system consists of two parabolic reflectors placed symmetrically facing each other. The first parabolic reflector collects and collimates it into a parallel beam. The second parabolic reflector intercepts the parallel beam and focuses the light with unity magnification, i.e. 1:1 imaging, into a tapered light pipe (TLP) with conserved brightness. The TLP transforms the focused light into an output with the needed area, shape, and numerical aperture (NA). It also acts as a homogenizer so that the intensity profile at the output surface is uniform and eventually provides a uniform intensity profile at the screen. The reflection of light twice in the dual paraboloid reflector system provides a high IR and UV rejection ratios, resulting in less degradation of the optical components. Polarization and color recycling systems are also designed taking advantage of this reflector configuration.

Microstrip feed with reduced aperture blockage

Abstract: A parabolic reflector is fed by a microstrip antenna supported at the focusy a tube aligned along the focal axis of the reflector. The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalties thereon or therefor.

Visual landing aids for aircraft

Abstract: Apparatus for aligning an aircraft landing aid projector of the type which comprises a light source located at the focus of a parabolic reflector, a lens mounted coaxially with the parabolic reflector and a filter disposed intermediate the reflector and lens close to the focal point of the lens. The apparatus comprises a base having a surface portion for supporting a projector, a lens for focussing light from the projector onto an image receiving means and means allowing observation of the image receiving means. The filter of a projector is correctly positioned when it appears in focus on the image receiving means.

Solar light collector

Abstract: PURPOSE:To obtain a solar light collector low in cost and high in utility efficiency, by a method wherein solar light focused by reflecting by a fixed parabolic reflector is received by a light receiver, and is led to a solar energy utilizing part by flexible optical fibers. CONSTITUTION:The ground surface 1 is depressed in a parabolic shape, and aluminum plates are adhered to the depressed part to constitute the parabolic reflector 3. An arcuate guide rail 4 is provided in the east-west direction by supporting it by supporting devices 5 used also as a heliostatic device, and the angle formed between the plane containing the guide rail 4 and the ground surface 1 is varied in accordance with the latitude of the sun by rotating the guide rail 4 in the directions of arrows A, B. The light receiver 6 is suspended from the guide rail 4 by a trolley 7 so that it can be moved in the directions of C, D, and is moved from the west to the east (direction C) in accordance with the position of the sun varying from the sunrise to the senset. The solar light received by the light receiver 6 is led to a light-to-heat converter 11 at the solar energy utilizing part 10 by the flexible optical fibers 8. Accordingly, it is unnecessitated to provide a tower or multiple movable heliostats, installation cost is reduced, and a tracking drive can be easily accomplished.