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Reflector (antenna)

About: Reflector (antenna) is a research topic. Over the lifetime, 28730 publications have been published within this topic receiving 212618 citations.


Papers
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Proceedings ArticleDOI
Senglee Foo1
09 Jul 2017
TL;DR: In this paper, an electronically beam-steerable flat reflector antennas using liquid-crystal-loaded metasurface was proposed, which can be reconfigured in real time to achieve effective beam collimation and beam steering by varying DC voltage distribution of the TTD cells.
Abstract: This paper presents concept of an electronically beam-steerable flat reflector antennas using liquid-crystal-loaded metasurface. Primary reflector of the proposed antenna concept utilizes metasurface comprising of a large number of reconfigurable true-time-delay (TTD) unit cells. Consequently, reflective phase of the metasurface reflector can be electronically reconfigured in real time to achieve effective beam collimation and beam steering by varying DC voltage distribution of the TTD cells.

59 citations

Patent
20 Mar 1978
TL;DR: In this article, a radiation collector is used for counting and analyzing a flow of dilute particulate material, such as blood cells, sperm cells and the like, through the use of light detection.
Abstract: Disclosed is a radiation collector apparatus and method primarily for counting and analyzing a flow of dilute particulate material, such as blood cells, sperm cells and the like, through the use of light detection. The radiation collector apparatus comprises a reflector chamber having an ellipsoidal reflector surface with a pair of elipsoidal foci defining a first focus, f 11 , and second focus, f 12 , and a second reflector surface with a primary focus, f 21 , positioned at the same point as focus f 12 , and a secondary focus, f 22 . The second reflector surface has the configuration of one of the conic sections of revolution. In operation the radiation collector apparatus is provided with an intensifed beam of light and a stream of particulate material aligned to intersect the intensifed beam of light at focus f 11 . Detectable light signals, after two reflections, are received in a focused beam by a photosensitive detector.

59 citations

Patent
28 Jun 1993
TL;DR: In this paper, a reflective type liquid crystal display device with a reflector film having excellent polarization preservation properties and an anisotropic diffusing film for diffusing only the light polarized in a particular direction is presented.
Abstract: A reflective type liquid crystal display device in accordance with the present invention includes a reflector film having excellent polarization preservation properties and an anisotropic diffusing film for diffusing only the light polarized in a particular direction. The anisotropic diffusing film is composed of a complex of liquid crystal and a polymer and selectively diffuses incident light. If a liquid crystal layer composed of dichroic dye and liquid crystal is employed, it becomes possible to carry out high contrast display with the anisotropic diffusing film and the reflector film and to prevent reflections of nearby objects appearing on the screen. Similarly, if a liquid crystal layer composed of liquid crystal and a polymer and having a twist angle of orientation of the liquid crystal specified to be in a range of 40° to 50° between an insulating substrate and a reflector member is employed, and the reflector film possesses excellent polarization preservation properties, similarly to the above case a reflective type liquid crystal display device can be obtained which reflects no nearby objects on the screen and can carry out high contrast display.

59 citations

Patent
26 Dec 1989
TL;DR: In this article, a pair of non-cooperating, optical beam transceivers are disposed so that optical alignment between them is possible, and a controller selectively causes one of the transcellers, while acquiring a communication link, to operate in a search mode, and the other to operate as a stare mode.
Abstract: A pair of remote non-cooperating, optical beam transceivers are disposed so that optical alignment between them is possible. A controller selectively causes one of the transceivers, while acquiring a communication link, to operate in a search mode, and the other to operate in a stare mode. Each transceiver has an optical axis and retro-reflects all incident beams which are not substantially aligned with the axis but does not reflect incident beams aligned with the axis. Each transceiver includes an axis-aligned beam transmitting source, a detector of incoming axis-aligned beams, a pointer for aiming the axis anywhere within a hemispherical range while searching for the other transceiver, a component which distinguishes between a retro-reflection of a transmitted beam and an incoming beam from another such transceiver, a sensor for quantitatively measuring the power of retro-reflected beam, a controller for moving the axis in an abbreviated search for a direction in which the power of a retro-reflected beam is maximum, and a beam tracker for maintaining boresight alignment once the transceivers' optical axes are aligned. Preferably, each transceiver includes a matched pair of reflecting telescopes rigidly mounted with their optical axes precisely aligned, one each for transmitting and one for receiving optical beams. Each telescope should include a primary reflector, a subreflector with a Cassegrainian focus behind the primary reflector, and a retro-reflector behind a vertex aperture in the primary reflector.

59 citations

Journal ArticleDOI
TL;DR: In this paper, a rangefinder is described that uses the propagation time of a beam of infrared radiation to measure distances of up to 120 m with errors of less than 50 μm.
Abstract: A rangefinder is described that uses the propagation time of a beam of infrared radiation to measure distances of up to 120 m with errors of less than 50 μm. The instrument is capable of measuring up to five different distances per second by directing an amplitude modulated infrared beam to a retroreflector located at the far end of each path. The instrument is being tested with the expectation that such a system could be used to make precise and rapid measurements on a large radio telescope. Such measurements would be used to adjust the shape of the telescope reflector surface to correct for thermal and gravitational deformations taking place during astronomical observations. It is possible that the measuring system could be extended to relate the positions of certain moving parts of the structure to a reference system fixed in the ground, thus opening the possibility of making corrections to the telescope pointing.

59 citations


Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20224
2021567
2020948
20191,159
20181,092
2017977