Cassegrain antenna

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

Microwave limb sounder

Abstract: A microwave limb sounder (MLS) to measure trace gases in the upper atmosphere by comparing spectral noise content of limb soundings with the spectral noise content of cold space utilizes an offset Cassegrain antenna system and a tiltable input mirror to alternately look out at the limb and up at cold space at an elevation angle of about 22° The mirror can also be tilted to look at a black body calibration target Reflection from the mirror is directed into a radiometer the head of which functions as a diplexer to combine the input radiation and a local oscillator (klystron) beam The radiometer head is comprised of a Fabry-Perot resonator consisting of two Fabry-Perot cavities spaced a number of half wavelengths apart Incoming radiation received on one side is reflected and rotated 90° in polarization by the resonator so that it will be reflected by an input grid into a mixer, while the klystron beam received on the other side is also reflected and rotated 90°, but not without passing some energy to be reflected by the input grid into the mixer

Design of parabolic solar concentrator to improve the optical efficiency for thermal engine generator using dual reflector Gregorian method

Abstract: Parabolic Dish Solar Concentrator (PDSC) are commonly used to generate electricity from thermal energy employing Stirling engine, steam, photovoltaic and thermoelectric generator. Heat concentrator of Parabolic Dish (PD) is used for focusing radiation of the sun into the receiver that connected to the generator system. The conventional generator system is located above the focus of the primary reflector parabolic dish. This paper presents a new design of the parabolic dish solar concentrator using dual reflector Gregorian method. The design applies an additional reflector to place the engine generator in the bottom of the primary reflector parabolic dish. The design was verified using “SolTrace”, a software package for tracing the solar ray. It found that the heat flux collected was 0.73 MW/m2 for the designed parabolic with 300 cm primary diameter. This parabolic have obtained 594.65x geometry concentration ratio and 84.27% optical efficiency.

Ground Antenna for Space Communication System

Abstract: The accurate tracking and telemetering of space probes requires the use of very sensitive receiving equipment and large antennas. The TRAC(E) system developed by the Jet Propulsion Laboratory utilizes an 85-foot-diameter, equatorially mounted, parabolic reflector. The antenna, similar to those used for radio astronomy, is located near Goldstone Lake near Barstow, Calif. The mechanical and electrical characteristics of the antenna and its subsystems are discussed, and its performance and the way it was used in tracking the lunar probe Pioneer IV are described. Limitations imposed on the space communication system by the ground antenna are discussed, and possible methods of improvement are listed.

Cassegrain Systems

Abstract: The effective F/D ratio for a parabolic-hyperbolic (Cassegrain) antenna system is shown under practical considerations to be only slightly larger than that of the parabola alone. Furthermore, when advantage is being taken of this increase in effective F/D ratio for the purpose of providing wider angle multiple beam antenna systems, it is shown that the size of the feed horn structure may become prohibitive.

Switching subreflector for millimeter wave radio astronomy

Abstract: A method of beam switching a Cassegrain antenna used for radio astronomy by tilting the hyperbolic secondary reflector is described. The system described has been in use for over a year at the 11‐m millimeter wave antenna operated by the National Radio Astronomy Observatory at Kitt Peak, Arizona.