Topic
Cassegrain antenna
About: Cassegrain antenna is a research topic. Over the lifetime, 3207 publications have been published within this topic receiving 28278 citations.
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01 Nov 2019
TL;DR: In this paper, the E-band at 71-76 GHz with 30 dBm of transmit power from a GaN-based solid-state power amplifier and a 3dB noise figure of its GaAs-based receiver is employed in a data transmission with up to 9.8 Gbit/s data rate between a plane and a ground station.
Abstract: A wireless communication link operating in E-band at 71-76 GHz with 30 dBm of transmit power from a GaN-based solid-state power amplifier and a 3-dB noise Figure of its GaAs-based receiver is employed in a data transmission with up to 9.8 Gbit/s data rate between a plane and a ground station. Flying at a height of 1000 m above ground and at distances between 5 and 12 km from the receiver, a microlight aircraft hosts the payload mounted to its wing. The highly directional link is formed by a 39.7 dBi gain Cassegrain parabolic antenna in the plane-mounted transmitter, and a 48.7 dBi Cassegrain antenna with GPS-based antenna tracking in the ground terminal. Stable data links were established with up to 9.8 Gbit/s data rate employing QPSK, 8-PSK and 16-QAM modulation.
10 citations
Patent•
13 Feb 2003TL;DR: In this paper, a second waveguide beneath the lower plate of the first waveguide and a 180% bend parabolic main reflector are used to reflect the energy beam to the upper plate of a traveling wave antenna.
Abstract: Steering of an electromagnetic beam of energy in the upper plate of a plate waveguide of a traveling wave antenna concurrently with the formation of a flat phase front and collimation of the electromagnetic beam is achieved by providing a second waveguide beneath the lower plate of the first waveguide and providing a 180% bend parabolic main reflector to reflect the energy beam to the upper plate of the upper waveguide. A feed horn is located in the lower waveguide and illuminates a pivotal subreflector which reflects the energy to the parabolic main reflector. By rotating the subreflector about its pivot point, the beam which is radiated to the upper waveguide is angularly shifted or steered.
10 citations
TL;DR: In this article, an adaptive nulling system for reflector antennas that uses a genetic algorithm to mechanically adjust scattering elements in order to place nulls in the sidelobes of cylindrical parabolic reflectors was described.
Abstract: This paper describes an adaptive nulling system for reflector antennas that uses a genetic algorithm to mechanically adjust scattering elements in order to place nulls in the sidelobes of cylindrical parabolic reflector antennas.
10 citations
Proceedings Article•
13 May 2015
TL;DR: An optimal beamforming algorithm for phased-array antenna systems designed to operate as focal plane arrays (FPA) in push-broom radiometers is presented, yielding much higher spatial and radiometric resolution as well as much closer distance to coast, as compared to the present-day systems.
Abstract: Strict requirements for future spaceborne ocean missions using multi-beam radiometers call for new antenna technologies, such as digital beamforming phased arrays. In this paper, we present an optimal beamforming algorithm for phased-array antenna systems designed to operate as focal plane arrays (FPA) in push-broom radiometers. This algorithm is formulated as an optimization procedure that maximizes the beam efficiency, while minimizing the side-lobe and cross-polarization power in the area of Earth, subject to a constraint on the beamformer dynamic range. The proposed algorithm is applied to a FPA feeding a torus reflector antenna (designed under the contract with the European Space Agency) and tested for multiple beams. The results demonstrate an improved performance in terms of the optimized beam characteristics, yielding much higher spatial and radiometric resolution as well as much closer distance to coast, as compared to the present-day systems.
10 citations
TL;DR: In this paper, a technique for approximating the radiation patterns of large size reflector antennas using a moment method without excessive computer time or memory is described, which increases only linearly with antenna size.
Abstract: A technique, whereby the radiation patterns of large size reflector antennas can be approximated by computers using a moment method without excessive computer time or memory, is described. Computational time increases only linearly with antenna size. There is no limit on the minimum reflector size (a single wire reflector can be analyzed). An example is discussed showing the radiation patterns of a truncated parabolic reflector excited by feeds displaced from the parabola focus.
10 citations