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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Patent•
05 Jun 1992
TL;DR: In this paper, a movable reflector (32) having a large number of flat reflective sides (44) and a deflector (16) is used to shift the laser beam at high speed across a plurality of the reflective sides.
Abstract: A laser beam scanning apparatus employs a movable reflector (32) having a large number of flat reflective sides (44) and a deflector (16) which shifts the laser beam (10) at high speed across a plurality of the reflective sides (44). The movement of the reflector (32) is synchronized with the deflection of the laser beam (10) to produce a desired scan pattern in a first scan direction (X). The reflective sides (44) of the movable reflector (32) may be angled relative to each other in a second direction (Y) to produce different scan lines thereby providing an X-Y scan pattern. The combined high speed beam deflection and motion of the reflector (32) provide scanning of the beam (10) in parallel scan segments thereby providing high scanning speed of the beam (10) with a high degree of resolution.
43 citations
43 citations
Patent•
18 Oct 1990
Abstract: A solar collector structure and method of fabrication are disclosed, the solar collector being of the linear, parabolic reflector-type. The parabolic reflector body includes an elongated layered structure having a concave parabolic reflective surface. The reflector body is supported and reinforced by a longitudinal beam member bonded to the convex backside of the layered structure. The layered structure includes a first reflective layer and a supporting molded layer formed of an amorphous hard-curing adherent material such as concrete or stucco. The entire reflector body structure is fabricated on an elongated convex mold. The method of fabrication includes forming the mold using a screed-moving apparatus which moves longitudinally along the mold. As the parabolic reflector body is formed on the mold, the screed-moving apparatus is again used to shape portions of the reflector body. A means for fabricating a parabolic reflector body, including both the elongated mold and the molded and reflective portions of the reflector body, together with the reinforcing longitudinal beam member, is also disclosed.
43 citations
TL;DR: In this paper, the sensitivity of boresight directivity to changing surface distortion parameters for fixed feed-array geometries is examined, and it is found that feed array compensation is feasible only for distortions with low spatial frequency content, such as those distortions induced by thermal and gravitational effects.
Abstract: Various aspects of reflector surface distortion compensation are explored by first assuming the reflector distortion is given and then designing the compensating feed array. The sensitivity of boresight directivity to changing surface distortion parameters for fixed feed-array geometries is examined. It is found that feed array compensation is feasible only for distortions with low spatial frequency content, such as those distortions induced by thermal and gravitational effects. The optimum directivity methods for determining element excitation is found to yield slightly better values of directivity than those for the conjugate field matching (CMF) technique. However, the CFM technique has, in general, much lower sidelobe levels and lends itself to simple realization in hardware. In view of these results, distortion compensation using an array feed is concluded to be a reasonable approach to improving antenna performance for large, space-based reflector antennas that are not easily accessible for tuning and have time-dependent surface distortions. >
43 citations
TL;DR: In this article, a VCSEL-based oxygen sensor for real-time combustion optimization in furnaces is presented, where a diffuse reflector instead of a spherical mirror is used to avoid alignment problems during thermal cycles during in-situ measurement.
Abstract: In this paper, a VCSEL-based oxygen sensor applied for real-time combustion optimization in furnaces is presented. A diffuse reflector instead of a spherical mirror is used to avoid alignment problems during thermal cycles the sensor is exposed to in the in-situ measurement. In spite of the signal loss, this concept proves to be suitable for measurements in the exhaust of a gas furnace even if severe condensation at the optic surfaces occurs. The optic cell has a background level in the order of 10−5 in absorbance and is long-term stable. A real-time microcontroller-suited curve fitting algorithm is applied to further improve the long-term stable operation of the whole sensor, because a drift of the spectral background is compensated. Neither absolute wavelength scale, nor absolute wavelength difference between two measurement points is needed for concentration determination. Furthermore, the gas pressure can be simultaneously determined. Kalman filtering is also applied to reduce the concentration measurement noise without losing the reliability and fast response time of the sensor. The techniques applied in the sensor are not limited to oxygen sensing, but also can be applied for sensing of other gas molecules.
43 citations