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.

Clip fasteners for parabolic dish reflector panels

Abstract: A parabolic reflector having support structure, preferably mounted on wheels for rotation, for supporting a dish framework to which is mounted a multiplicity of adjacently placed reflector members for focusing solar rays on a linear collector. The reflector members are in the form of sheets having the shape of funnel sections, i.e., infundibuliform, to provide a reflective concave surface. Each of the reflector members define slots which are aligned with and adjacent like slots of adjacently placed reflector members for receiving bendable tabs of clip fasteners. The clip fasteners, besides serving to securely connect adjacent reflector members, also include apertures for receiving rivets or other fasteners for attachment to the underlying parabolic framework. The clips include a reflective surface for maximizing reflector efficiency. The linear collector includes a cylindrical, elongated shell for receiving focused solar rays. Heat exchange media flows upward into the collector through a central tube which is separated from the exit passage adjacent the shell by means of solid insulative material to prevent heat exchange between the incoming and exiting heat exchange media.

Bent Glass Optics

Abstract: The paper describes how a glass strip may be bent to match any curve of large radius of curvature, to a high degree of accuracy, so that it may be used as a glancing incidence X-ray or extreme ultraviolet optical element. The desired match is obtained by applying a suitable combination of end couples and adjusting the cross-sectional moment of inertia along the length of the strip by varying its breadth. Two applications are described; a parabolic reflector for use as a laboratory X-ray collimator for testing mechanical collimators to be used in space instruments, and an elliptical reflector for point-to-point focussing. The latter device has been used for testing gratings in the X-ray and extreme ultraviolet (EUV) regions and for concentrating radiation on the entrance slit of a spectrometer, with a resultant gain in speed and resolution. It is suggested that the technique may have other laboratory and space applications, which are briefly described.

Gridded Vivaldi Antenna Feed System for the Northern Cross Radio Telescope

Abstract: The design of a broadband antenna feed system for the cylindrical offset parabolic reflector of the Italian Northern Cross radio telescope is described. Its operative frequency band spans from the Low Frequency Array (LOFAR) upper band, i.e. 120-240 MHz, to the present telescope operative band centered at 408 MHz. The proposed configuration consists of a linear array of gridded Vivaldi (tapered slot) radiators inside a wired subreflector. Numerical simulations have been carried out using both commercial software and a specialized Method-of-Moments approach. They show that the designed feed system provides both a good impedance matching and an efficient illumination of the main reflector in the overall frequency band.

Phosphor light source, its manufacturing method, light source device, and lighting system

Abstract: PROBLEM TO BE SOLVED: To materialize a small phosphor light source having high light intensity without increasing light intensity of exciting light. SOLUTION: This phosphor light source is disposed in the vicinity of the focus of a rotating parabolic mirror. The phosphor light source emits fluorescence with the exciting light radiated from the rotation axis direction of the rotating parabolic mirror, and has a base substance 70 and a phosphor part 80. The exciting light irradiated surface of the phosphor part 80 is formed into a non-planar shape having microscopic projecting and recessed parts. COPYRIGHT: (C)2007,JPO&INPIT

Analysis of aperture illumination and edge rolling effects for parabolic reflector antenna design

Abstract: The radiation from parabolic reflector antennas for different amplitude and phase aperture illumination patterns is treated and the minimizations of the edge diffraction effects by edge rolling techniques are investigated in an accurate manner. The analytical regularization method (ARM) is used to solve the problem of E-polarized wave diffraction by parabolic shaped perfectly electrical conductive (PEC) cylindrical reflector with finite thickness. The initial boundary value problem is reduced to the infinite algebraic system of the second kind, which is an equation that can in principal be solved with any predetermined accuracy by means of the truncation procedure. The parabolic reflector is illuminated by a fictive feeder antenna which produces the desired phase and amplitude field distributions over the antenna aperture. Some edge rolling structures are analyzed to suppress the side and back lobes and to improve the aperture efficiency. The ARM procedure is verified by the analytical solutions and the calculated field patterns are presented for typical antenna configurations.