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.

Computer-aided design of reflector antennas: the Green Bank Radio Telescope

Abstract: This paper presents an evaluation of the electrical performance of the Green Bank Telescope (GBT) reflector antenna, operating as single- and dual-offset configurations, as well as a general overview of the GBT system. The GBT dual-offset Gregorian configuration is designed for low cross polarization (XPOL) using the dual-offset reflector antenna (DORA) synthesis package code developed by the authors. The procedure implemented in DORA to upgrade an existing main reflector to a low cross-polarized dual-offset Gregorian reflector antenna is also described in this paper. All computed patterns were obtained with the parabolic reflector analysis code (PRAC) program, also developed by the authors, and with the commercial code GRASP7. The GBT radiation patterns and performance values, which include original data not available anywhere else as far as the authors know, indicate that low XPOL performance can be achieved with a dual-offset configuration, provided that a low XPOL feed is used. The GBT configuration is employed as a case example for the aforementioned procedure. However, an effort is made to present the main conclusions as generically as possible.

Radio waves radiators

Abstract: The object of this invention consists in a new system for radiating radio waves, more particularly applicable to the ultra-short waves band, for instance of the decimeter order. There is known a system which consists in a combination of a parabolic mirror and of a dipole disposed in the focus...

Optical assemblies for concentration of radial light distribution within confined luminaire packages

Abstract: An optical assembly for architectural illumination which includes a quasi point source surrounded by a collimating ring lens designed to radially project collimated beams. A segmented, off axis, parabolic reflector to collect and reflect light (not gathered by the collimating ring lens) as collimated beams and a ring reflector, the segments of which designed to gather beams from both the collimating ring lens and the off axis reflector and the direct them in substantially the same direction.

Experimental Analysis of Parabolic Solar Dish with Copper Helical coil Receiver

Abstract: Solar Parabolic Dish is currently used for the Water heating and cooking applications. Generally Solar Parabolic Dishes are fixed focus point concentrators, but in order to achieve higher thermal efficiency we tried to make it line focus concentrator by using a unique receiver (copper tube in the form of helical coil) mounted at focal point.This report presents experimental platform based on the design, development and performance characteristics of direct steam generation by non-tracking solar paraboloidal dish concentrating system. The performance of the concentrator is experimentally investigated with the water circulated as heat transfer fluid. The system is fabricated with highly reflective aluminium foil sheet (0.8 reflectance factor). The experimental setup is placed in open, and the tests were carried out. The collector's efficiency was noted. The results are encouraging to provide the data for developing steam generation for rural application. The concentrated heat is absorbed by a copper tube which is made up of coil in a curved shape (22cm diameter and length with 15 no of turns) and it is fixed on solar trace path in which, it is eliminates tracking the sun in the east west direction and optimal tracking of the sun in the north-south to obtain maximum solar energy. The experimental results are taken on summer and cloud free days. The test results were measured 215 o C with solar steam conversion efficiency is 60-70%

Environmental distortion measurement of curved antenna dishes

Abstract: A system for measuring the effect of deformation of an antenna parabolic reflector dish on the feedhorn focal point location. A plurality of equally spaced tiny mirrors attached to the parabolic reflector in a concentric circle reflects light onto a photographic plate mounted in front of the feedhorn focal point. The photographic plate contains a predrawn target circle which represents the projected focal point determined from the selected placement position of the tiny mirrors on the parabolic dish. A bore sight apparatus is used to align the parabolic dish with a light source, such as the sun. Spots, representing images of the sun reflected from the tiny mirrors, are recorded on the photographic plate when it is exposed. For a true parabola, the sun images produced by the tiny mirrors on the photographic plate should, theoretically, all fall on the target circle. Thus, any sun images on the photographic plate displaced from the target circle are an indication of distortion of the parabolic dish due to environmental changes.