Topic
Reflector (antenna)
About: Reflector (antenna) is a research topic. Over the lifetime, 28730 publications have been published within this topic receiving 212618 citations.
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TL;DR: In this article, a vertical-cavity surface-emitting laser with high contrast distributed Bragg reflectors on both sides of the cavity is presented, where the upper reflector consists of a six pair ZnSe/MgF quarter-wave stack, while the lower reflector is fabricated using selective oxidation.
Abstract: Data are presented on vertical-cavity surface-emitting lasers that use high contrast distributed Bragg reflectors on both sides of the cavity. The upper reflector consists of a six pair ZnSe/MgF quarter-wave stack, while the lower reflector consists of an eleven pair AlxOy/GaAs stack fabricated using selective oxidation. Strain due to the lower reflector is reduced by using AlxOy layers of less than a quarter-wave thickness. Device sizes ranging from 1 to 7 μm diameters are characterized, with a minimum threshold current of 53 μA.
58 citations
Patent•
01 May 1998TL;DR: In this paper, a system utilizing a series of three mirrors for collecting, concentrating, collimating, and distributing radiant flux, such as sunlight or moonlight, is described, where a structural framework supports the three reflectors and includes a light pipe, or other light distributing channel, through which the collected light is sent.
Abstract: A system utilizing a series of three mirrors for purposes of collecting, concentrating, collimating and distributing radiant flux, such as sunlight or moonlight. The system generally includes a first parabolic reflector having a hole formed centrally therethrough, a second parabolic reflector slightly smaller in diameter than the hole formed through the first reflector and attached in spaced relation thereto, such that the two reflectors share a common optical axis, and a third, planar reflector. A structural framework supports the three reflectors and includes a light pipe, or other light distributing channel, through which the collected light is sent. First and second motors actuate gear assemblies attached to the framework to cause the reflectors to track both the elevation and azimuth angles, respectively, of the sun and/or moon. One microprocessor operatively attached to position sensor assemblies incorporated into each of the motors, sends elevation and azimuth angle data to the sensors at predetermined intervals throughout each day, ultimately causing the motors to continuously adjust the position of the reflectors such that the first and second reflectors' optical axis is perfectly aligned with the elevation and azimuth angle of the sun, or moon, thereby maximizing the system's potential collection of radiant flux.
58 citations
Patent•
05 Dec 1997
TL;DR: In this article, an electric appliance includes a first electric power supply of first batteries arranged in a first pattern, and alternatively a different second electric supply of second batteries arranged on a second pattern.
Abstract: An electric appliance includes a first electric power supply of first batteries arranged in a first pattern, and alternatively a different second electric power supply of second batteries arranged in a second pattern. An electrical ON-OFF switch has an ON-OFF position push-button switch actuator ard a rotary switch actuator which releasably blocks that ON-OFF position push-button switch actuator in an OFF position. A tail end is equipped with a bistable OFF and ON switching function and with a momentary ON switching function unified into one electric toggle switch having a stable OFF position, a stable ON position, and a momentary ON position. A flashlight beam is cast with a first lamp and reflector assembly, an alternative second lamp and reflector assembly is substituted for that first lamp and reflector assembly and a second light beam of a different configuration is cast with that alternative second lamp and reflector assembly.
58 citations
TL;DR: In this article, a new simulation tool consisting of several open-source software packages with the bifacial solar cell model is developed to predict the yearly yield of the solar panel with the reflector accurately, including the effects of the temperature changes in solar cells and the variation in solar irradiance incident on both front and rear sides at different time in a day.
58 citations
TL;DR: In this article, a high-gain horizontally polarised antenna for ultra wideband (UWB) operation is presented and experimentally demonstrated using a frequency selective surface (FSS) reflector.
Abstract: The design of a high-gain horizontally polarised antenna for ultra-wideband (UWB) operation is presented and experimentally demonstrated. Gain enhancement is achieved by using a frequency selective surface (FSS) reflector. Both the antenna and the FSS have simple structures and are printed on a similar substrate. The antenna is a three-stepped narrow rectangular slot excited using a three-stepped microstrip feed line. By optimising the lengths and widths of the sections of the slot and the feed line, an ultra-wide impedance bandwidth (3.2–12 GHz, measured) has been achieved. The FSS is a two-layer structure where each layer is an array of rectangular patches printed on one side of the substrate. With the application of the FSS, the antenna gain is enhanced by 3–4 dBi over most of the band. The polarisation purity (in terms of the measured cross-polar difference) is also improved with the FSS. Such an antenna–FSS combination will be useful for high-gain UWB applications requiring horizontal polarisation.
58 citations