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.

Triangular shape geometry in a Solarus AB concentrating photovoltaic-thermal collector

Abstract: Solar Energy can be used in various ways: there are solar collectors to heat water and air, photovoltaic panels that produce electricity and PVT collectors (Photovoltaic Thermal Collectors), which are basically a hybrid solution. Over recent years, much attention has been focused on an emerging solar technology: solar concentrators. These devices are used to reflect and focus solar radiation in the desired location, normally on photovoltaic cells, bringing enormous benefits because the latter continue to have a huge cost in the panels and concentrators allow a reduction in the number of cells. In this work, firstly, it is intended to make a study of photovoltaic cells, analyzing the behavior for different environ- mental factors that affect its operation: irradiance, temperature and shading. Then, a different type of concentrator is studied: triangular concentrator. Most of the analysis is made using a Software intended to simulate solar rays trajectory: Wendelin et al. (SolTrace, National Renewable Energy Laboratory (NREL), Golden, 2012). This Software allows to conclude about in which conditions it is collected the highest power in the receiver and do a comparison with another type of concentrator the parabolic concentrator where we try to understand in which months and tilts the two reflectors are more beneficial in terms of power collected by the panel. Finally, computationally results are compared with experimental results with respect to efficiencies and power collected and generated by solar panel, for a particular day of the year and for an aluminium reflector with a certain tilt and aperture. The results show that triangular reflector is a promising reflector because, with great simplicity of construction, allows higher powers than parabolic reflector, for certain times of the year. Besides, it should be noted that, for certain conditions, power collected at the bottom part of the receiver is greater than the upper part.

Integral equation analysis of an arbitrary-profile and varying-resistivity cylindrical reflector illuminated by an E-polarized complex-source-point beam.

Abstract: A two-dimensional reflector with resistive-type boundary conditions and varying resistivity is considered. The incident wave is a beam emitted by a complex-source-point feed simulating an aperture source. The problem is formulated as an electromagnetic time-harmonic boundary value problem and cast into the electric field integral equation form. This is a Fredholm second kind equation that can be solved numerically in several ways. We develop a Galerkin projection scheme with entire-domain expansion functions defined on an auxiliary circle and demonstrate its advantage over a conventional moment-method solution in terms of faster convergence. Hence, larger reflectors can be computed with a higher accuracy. The results presented relate to the elliptic, parabolic, and hyperbolic profile reflectors fed by in-focus feeds. They demonstrate that a partially or fully resistive parabolic reflector is able to form a sharp main beam of the far-field pattern in the forward half-space; however, partial transparency leads to a drop in the overall directivity of emission due to the leakage of the field to the shadow half-space. This can be avoided if only small parts of the reflector near the edges are made resistive, with resisitivity increasing to the edge.

A Compact Pattern Reconfiguration Antenna Based on Multimode Plane Spiral OA

Abstract: Over the past decades, orbital angular momentum (OAM) has attracted great interest due to its helical phase characteristics. It has been proved that plane spiral OAM (PSOAM) waves have a potential in azimuthal pattern reconfiguration. PSOAM waves could be termed as a special form of OAM wave, which avoids the inconsistency of the divergent angles for different OAM waves. However, from a practical point of view, such a PSOAM-based pattern reconfiguration scheme badly needs a compact high-purity multimode PSOAM antenna. In this communication, a compact high-purity eight-mode PSOAM antenna consisting of a coaxial resonator group (CRG) and a rotating parabolic reflector (RPR) is fabricated and measured. The prototype is designed for $X$ -band operation with a bandwidth of 140 MHz, and the simulated efficiencies of the PSOAM modes ±1,±2,±3, and ±4 are 88.86%, 92.18%, 90.93%, and 91.25%, respectively. The constructed pattern may have the directivity, vorticity, and nondistortion azimuthal 360° scanning capability. This scheme realizes these pattern characteristics with a simpler algorithm and a lower system complexity compared with the phased array antenna-based pattern reconfiguration scheme. It will have potential in next-generation radar and wireless communication system.

A transform technique for computing the radiation pattern of prime-focal and Cassegrainian reflector antennas

Abstract: An efficient numerical method based on the use of the fast Fourier transform (FFT) algorithm is developed for computing radiation patterns of aperture antennas with given aperture distributions. The method is also readily applicable to the problem of computing the radiation pattern of paraboloidal reflector antennas when the induced surface currents on the surface of the reflector are known. Using an efficient launching and scanning scheme for subreflector analysis, the method is extended to a Cassegrainian reflector antenna system.