Cassegrain antenna

About: Cassegrain antenna is a research topic. Over the lifetime, 3207 publications have been published within this topic receiving 28278 citations.

Phase retrieval in the radio holography of reflector antennas and radio telescopes

Abstract: Methods of phase retrieval from simulated intensity information have been tested for use in the radio holography of reflector antennas In numerical simulations the Misell algorithm has been used successfully to retrieve the aperture phase distribution from two numerically simulated power polar diagrams, one in focus and the second defocused The technique uses no auxilliary reference antenna However, it does need a high signal to noise ratio, typically 50 dB if a 60 \times 60 array is to be measured to a precision such that the gain is within 1 percent of ideal It should be most useful where no direct phase measurements are possible and ground-based or satellite transmitters can be used as sources The use of astronomical maser sources (22 GHz) can give information on large scale deformations

Satellite-tracking millimeter-wave reflector antenna system for mobile satellite-tracking

Abstract: A miniature dual-band two-way mobile satellite-tracking antenna system mounted on a movable vehicle includes a miniature parabolic reflector dish having an elliptical aperture with major and minor elliptical axes aligned horizontally and vertically, respectively, to maximize azimuthal directionality and minimize elevational directionality to an extent corresponding to expected pitch excursions of the movable ground vehicle. A feed-horn has a back end and an open front end facing the reflector dish and has vertical side walls opening out from the back end to the front end at a lesser horn angle and horizontal top and bottom walls opening out from the back end to the front end at a greater horn angle. An RF circuit couples two different signal bands between the feed-horn and the user. An antenna attitude controller maintains an antenna azimuth direction relative to the satellite by rotating it in azimuth in response to sensed yaw motions of the movable ground vehicle so as to compensate for the yaw motions to within a pointing error angle. The controller sinusoidally dithers the antenna through a small azimuth dither angle greater than the pointing error angle while sensing a signal from the satellite received at the reflector dish, and deduces the pointing angle error from dither-induced fluctuations in the received signal.

A method for producing a shaped contour radiation pattern using a single shaped reflector and a single feed

Abstract: Eliminating the corporate feed network in shaped contour beam antennas will reduce the expense, weight, and RF loss of the antenna system. One way of producing a shaped contour beam without using a feed network is to use a single shaped reflector with a single feed element. For a prescribed contour beam and feed, an optimization method for designing the reflector shape is given. As a design example, a shaped reflector is designed to produce a continental-United-States (CONUS) coverage beam. The RF performance of the shaped reflector is then verified by physical optics. >

Design of wide-band corrugated conical horns for Cassegrain antennas

Abstract: Design procedures based on extensive theoretical and experimental investigations are given for hybrid-mode corrugated conical horns having near-constant beamwidth, low cross-polarized sidelobes and low reflection for continuous bandwidths up to 2.1:1. The design techniques are applicable for horn flare semi-angles to about 30\deg , which includes most feed horns in dual-reflector antennas.