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.

Dual-Polarised Mode Generator for Cross-Polar Ccmpensation in Offset Parabolic Reflector Antennas

Abstract: It has been recently shown that the depolarisation and beam-squinting effects exhibited by offset parabolic reflector antennas can be suppressed by means of techniques based upon focal-plane field matching and the use of higher-order wave-guide modes. In the past prototype examples of such `matched-feed' devices have been limited to operation with a single hand of polarisation. The limitation has largely been imposed by the performance of the mode generating section of the matched-feed device. This paper describes the salient features of the design and evaluation of a compact dual-polarised mode-generator which provides a means of achieving simultaneous suppression of the cross-polar radiation for two orthogonal linear polarisations. Experimental data, obtained with a K-band prototype device, validate the overall performance of the mode generator when used within a matchedfeed' device to illuminate an accurately profiled offset parabolic reflector.

Characterization of dense focal plane array feeds for parabolic reflectors in achieving closely overlapping or widely separated multiple beams

Abstract: [1] In the advent of modern mobile satellite communications requiring rapid and adaptive multiple beams, this work studies the ability of reflector antennas fed by dense focal plane arrays (FPA) in achieving arbitrarily shaped and sized footprints to meet the demands In this paper, the efficiencies of single off-axis as well as multiple beams of FPA-fed paraboloids are investigated The offset FPA considered here comprises hard rectangular waveguides The focal plane field, which the FPA samples, is synthesized by integration of the physical optics induced electric currents over the reflector surface caused by the off-axis incident plane wave arriving at that incidence angle of interest Full mutual coupling analysis has been performed in the FPA sampling, thereby taking into account mutual coupling losses in the arrays The fields over the tilted elliptical aperture of off-axis beams needed for calculation of the aperture efficiency are obtained by projecting the usual focal plane fields to this tilted aperture using geometrical optics Results show that the total efficiency of the offset FPA-fed reflector decreases with increasing beam angle and increases with larger number of FPA elements It is also found that the maximum directive gain of the reflector radiation patterns falls noticeably with beam angle when the FPA population is low, but the directivity can be maintained well when an adequate number of FPA elements are used Multiple beams that are either closely overlapping or widely separated are also successfully investigated

Parabolic dish and method of constructing same

Abstract: A parabolic dish is constructed by forming from relatively thin flexible sheet material a planar assembly of relatively narrow curved strips arranged side by side and having arcuate longitudinal edges which conform to curves defined by certain parametric equations, such that the strip assembly may be deformed to a parabolic dish configuration wherein the adjacent strip edges are disposed contiguous one another in planes parallel to a plane containing the principle axis of the dish, and joining the strips of the deformed strip assembly to retain the latter in its parabolic dish configuration. A polarizing parabolic dish antenna reflector is constructed by forming on the strips of the planar strip assembly, as by a photoetching process, a plurality of arcuate electrically conductive grid elements conforming to curves established by the parametric equations and bonding the strip assembly in its deformed parabolic dish configuration to a parabolic reflector dish to provide on the parabolic surface of the dish a polarizing grid comprising the grid elements disposed side by side in equally spaced planes parallel to a plane containing the principle axis of the dish.

Solar energy collector

Abstract: A solar energy collector comprising a collector core located within a longitudinal parabolic reflector and formed of a series of spaced tubes exposed to the direct rays of the sun and to rays reflected by the reflector and arranged in a cylindrical array extending longitudinally to form a fluid path between two end annular manifolds connected at opposite ends of a storage tank located within the array.