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.

Ray Tracing Study of Optical Characteristics of the Solar Image in the Receiver for a Thermal Solar Parabolic Dish Collector

Abstract: This study presents the geometric aspects of the focal image for a solar parabolic concentrator (SPC) using the ray tracing technique to establish parameters that allow the designation of the most suitable geometry for coupling the SPC to absorber-receiver. The efficient conversion of solar radiation into heat at these temperature levels requires a use of concentrating solar collectors. In this paper detailed optical design of the solar parabolic dish concentrator is presented. The system has diameter mm and focal distance mm. The parabolic dish of the solar system consists of 11 curvilinear trapezoidal reflective petals. For the construction of the solar collectors, mild steel-sheet and square pipe were used as the shell support for the reflecting surfaces. This paper presents optical simulations of the parabolic solar concentrator unit using the ray tracing software TracePro. The total flux on the receiver and the distribution of irradiance for absorbing flux on center and periphery receiver are given. The goal of this paper is to present the optical design of a low-tech solar concentrator that can be used as a potentially low cost tool for laboratory scale research on the medium-temperature thermal processes, cooling, industrial processes, polygeneration systems, and so forth.

Offset-Feed Surface Mesh Generation for Design of Space Deployable Mesh Reflectors

Abstract: Surface mesh geometry is crucially important to the performance of deployable mesh reflectors. This paper presents new results from a continued research effort to design the pseudo-geodesic mesh geometry for offset-feed parabolic mesh reflectors and to fulfill the operating frequency requirements in related applications. The proposed method is applied to two offset parabolic reflector examples. The geometries so generated satisfy the surface accuracy and offers the exact presentation of desired working shape at its best-fit surface. Additionally, a comparative discussion shows that the design results by the proposed method always have the simplest mesh topology, the minimum total length, and competitive surface RMS errors.

A mesh reflecting surface with electrical characteristics independent on direction of electric field of incident wave

Abstract: For large deployable antennas on board satellites, a knitted wire mesh is used as reflecting surface because it is lightweight and elastic due to its knitted structure. The mesh reflecting surface has high reflectivity for the electric field parallel to the wire running direction (Takano, T. et al., 1992). This nature of the mesh, the dependence of reflectivity on the direction of the incident wave's polarization, causes a problem that the axial ratio of a circularly polarized wave degrades. We previously reported the transmission loss of mesh reflecting surfaces made from meshes woven in conventional ways (Miura, A. and Tanaka, M., IEEE Topical Conf. on Wireless Commun. Technology, 2003). We now introduce a mesh reflecting surface woven in a new manner. This mesh has an adequate reflectivity with small variation of reflectivity depending on the direction of the electric field of the incident wave. The measured electrical characteristics of this mesh reflector are reported and compared with those of two conventional mesh reflecting surfaces. Parabolic reflector antennas have been made from the three meshes and their radiation patterns with a circularly polarized incident wave have been measured.

A Fourier Optics Tool to Derive the Plane Wave Spectrum of Quasi-Optical Systems [EM Programmer's Notebook]

Abstract: We present a freely accessible graphical user interface (GUI) for analyzing antenna-fed quasi-optical (QO) systems in reception (Rx). This analysis is presented here for four widely used canonical QO components: parabolic reflectors and elliptical, extended hemispherical, and hyperbolic lenses. The employed methods are geometrical optics (GO) and Fourier optics (FO). Specifically, QO components are illuminated by incident plane waves. By using a GO-based propagation code, the scattered fields are evaluated at an equivalent sphere centered on the primary focus of the component. The FO methodology is then used to represent the scattered fields over the focal plane as plane wave spectrum. A field correlation between this spectrum and the antenna feed radiating without the QO component is implemented to evaluate the induced open-circuit voltage on the feed in Rx. By performing a field matching between these two spectral fields, feed designers can optimize the broadside and/or steering aperture efficiencies of QO systems in a fast manner. The tool is packaged into a MATLAB GUI, which reports the efficiency terms, directivity, and gain patterns of antenna-coupled QO systems. The described tool is validated via full-wave simulations with excellent agreement.