3 edition of System overview on electromagnetic compensation for reflector antenna surface distortion found in the catalog.
System overview on electromagnetic compensation for reflector antenna surface distortion
1993 by National Aeronautics and Space Administration, National Technical Information Service, distributor in [Washington, DC], [Springfield, Va .
Written in English
|Statement||R.J. Acosta, A.J. Zaman, and J.D. Terry.|
|Series||NASA technical memorandum -- 106217., NASA technical memorandum -- 106217.|
|Contributions||Zaman, A. J., Terry, J. D., United States. National Aeronautics and Space Administration.|
|The Physical Object|
So a parabolic antenna ; is a high gain reflector antenna. It is used for television, radio and data communications. It may also be used for radar on the UHF and SHF sections of the electromagnetic spectrum. 43 Reflector Antenna. Reflector antenna such as parabolic antenna are composed of primary radiator and a reflective mirror. $\begingroup$ it is very unlikely that a reflector antenna's performance is limited by the conductivity of the metal. Much more important to efficiency, back and side lobe levels, is the blockage from the feed and/or struts holding the subreflector. $\endgroup$ – hyportnex Jul 17 '15 at Basic Antenna Theory and Concepts. ICS Communication Technologies ; Class 11; 2 Introduction. An antenna is an electrical conductor or system of conductors ; Transmission - radiates electromagnetic energy into space ; Reception - collects electromagnetic energy from space ; In two-way communication, the same antenna can be used for. The following groups do significant amounts of research into antennas, rather than just the odd paper here and there. If you wish to add your group added to the list, please provide evidence in the form of a link to their antennas research group, and some links to papers their staff have published in journals such as those from the IEEE - not just conference proceedings.
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SYSTEM OVERVIEW ON ELECTROMAGNETIC COMPENSATION FOR REFLECTOR ANTENNA SURFACE DISTORTION R.J. Acosta,* A.J° Zaman and J°D. Terry National Aeronautics and Space Administration Lewis Research Center Cleveland, Ohio Introduction The system requirements and hardware implementation for electro-magnetic compensation of antenna performance degradations.
System overview on electromagnetic compensation for reflector antenna surface distortion Conference Paper (PDF Available) August with 27 Reads How we measure 'reads'. Get this from a library.
System overview on electromagnetic compensation for reflector antenna surface distortion. [R Acosta; Afroz J M Zaman; John D Terry; United States. National Aeronautics and Space Administration.].
System overview on electromagnetic compensation for reflector antenna surface distortion - NASA/ADS The system requirements and hardware implementation for electromagnetic compensation of antenna performance degradations due to thermal effects was investigated. The system requirements and hardware implementation for electromagnetic compensation of antenna performance degradations due to thermal effects was investigated.
Future commercial space communication antenna systems will utilize the 20/30 GHz frequency spectrum and support very narrow multiple beams ( deg) over wide angle field of view ( System overview on electromagnetic compensation for reflector antenna surface distortion.
By J. Terry, The system requirements and hardware implementation for electromagnetic compensation of antenna performance degradations due to thermal effects was investigated.
Future commercial space communication antenna systems will utilize the 20 Author: J. Terry, R. Acosta and A. Zaman.
Compensation of Reflector Antenna Surface Distortion Using an Array Feed Article (PDF Available) in IEEE Transactions on Antennas and Propagation 37(8) - September with 57 Reads. A comer reflector is shown in Figure Most comer reflectors have an angle of 90°, but other angles are also used.
The feed element of the comer reflector is almost always a dipole or an array of cylindrical dipoles placed parallel to the vertex at a distance d, as shown in the figure.
Often, if the wavelength λ surface of the comer reflector can be replaced by a wire grid, thus. With the development of radio telescope antennas with large apertures, high gain, and wide frequency bands, compensation methods, such as mechanical or electronic compensation, are obviously essential to ensure the electrical performance of antennas that work in complex environments.
Since traditional compensation methods can only adjust antenna pointing but not the surface accuracy, Author: Congsi Wang, Congsi Wang, Haihua Li, Kang Ying, Qian Xu, Na Wang, Baoyan Duan, Wei Gao, Lan Xiao, Yu. Real-time detection and compensation of reflector surface errors is enabled for large reflector antennas such as inflatable antennas for Earth and space science applications.
NASA’s Jet Propulsion Laboratory, Pasadena, California By probing the field on a small subre-flector at a minimal number of points, the main reflector surface errors can.
Modern utilizations of reflector antennas in radars, satellite communications and tracking, remote sensing, radio astronomy, and the like have resulted in the development both of sophisticated reflector antenna configurations and of analytical and experimental design techniques.
Reflector Antennas – An Overview of Surface Distortion Effects Reflector antenna surface distortions may be slowly varying, rapidly varying, systematic or random. Typical examples of each of these types of surface distortions are presented and their consequences on the peak gain and side lobe performance are illustrated.
System overview on electromagnetic compensation for reflector antenna surface distortion Proceedings of IEEE Antennas and Propagation Society International Symposium Published: Microelectromechanical Systems (MEMS) Actuated Wave Front Correcting Subreflector: Distortion Compensation for Large Reflector Antennas William A.
Imbriale(1), Yahya Rahmat-Samii(2), Harish Rajagopalan(2) Shenheng Xu(2) and Vahraz Jamnejad(1) (1) Jet Propulsion Laboratory, California Institute of Technology. Acosta has written: 'System overview on electromagnetic compensation for reflector antenna surface distortion' -- subject(s): Antennas, Reflector, Phased array antennas, Reflector Antennas 'ACTS.
The purpose of the reflector antenna is to concentrate the radiation from a desired direction as effectively as possible in The electromagnetic (EM) analysis of the antenna provides the basis for the definition and specification of the geometrical layout.
or equivalently the distorted reflector surface, defined over the aperture area of Author: Jacob W. Baars, Hans J. Kärcher. Antennas & Propagation CS Spring Rajmohan Rajaraman. Introduction An antenna is an electrical conductor or system of conductors oTransmission - radiates electromagnetic energy into space oReception - collects electromagnetic energy from space In two-way communication, the sameFile Size: KB.
The distance between B′ and the focal axis of the subreflector is, which leads to a lateral displacement. where is the distance between points B and N, and is the distance between points N′ and F.
is the beam deviation factor, which is related to the ratio of the paraboloid focal distance to its open diameter and aperture-field : Jie Zhang, Jie Zhang, Jin Huang, Wei Liang, Youran Zhang, Qian Xu, Letian Yi, Congsi Wang.
This book provides a broad and applications-oriented introduction to electromagnetic waves and antennas, with MATLAB examples.
Current interest in these areas is driven by the growth in wireless and fiber-optic communications, information technology, and materials science. Reflector Antenna Surface Distortion Using an Array Feed,” IEEE Transactions on Antennas Propagation, vol.
37, pp.August  S. Rao, “Parametric Design and Analysis of Multiple-beam Reflector. Reflector Antennas Paraboloidal Reflectors Antennas useful for radio astronomy at short wavelengths must have collecting areas much larger than the collecting area Õ=(4Ù) of an isotropic antenna and much higher angular resolution than a short dipole provides.
Near-field vs Far-field Any antenna can be successfully measured on either a near-field or far-field range, with appropriate In Dan Slater wrote a comprehensive book titled "Near-Field Antenna Measurements" about the of anomalies in radomes and in detection of surface distortion in parabolic reflector antennas.
Acosta has written: 'System overview on electromagnetic compensation for reflector antenna surface distortion' -- subject(s): Antennas, Reflector, Phased array antennas, Reflector Antennas. antenna in orbit. Consequently, certain changes were observed at the reception level at ground stations, which were presumably caused by thermal distortion of the large antenna’s reflectors.
Also, we compensated beams using the electrical beam shifting function of the power feeding section and reduced the variation width of reception levels. A directional antenna system is disclosed and generally includes a passive conical reflector and an active feed assembly comprising a plurality of effective half-wave dipoles or element radiators and extending perpendicular thereto.
The dipoles are simultaneously excited by in-phase signal energy so as to produce electromagnetic wave energy which is directed to the conical reflector and Cited by: R. Acosta has written: 'System overview on electromagnetic compensation for reflector antenna surface distortion' -- subject(s): Antennas, Reflector, Phased array antennas, Reflector Antennas.
Radio wave reflection. When a radio wave or in fact any electromagnetic wave encounters a change in medium, some or all of it may propagate into the new medium and the remainder is reflected. The part that enters the new medium is called the transmitted wave and the other the reflected wave.
Typically, the shock waves will deform the surface of reflector antennas and fragments will perforate them. In this paper, the deformation and perforation of reflector antennas are considered.
The reflector antenna is shown in Fig. 2; the caliber is m. The feed of the reflector antenna is a dual-mode horn. Download: Download full-size imageCited by: 3.
antenna have a strong influence on the antennas electrical features (Fig. The principle of an antenna can be shown by bending a co-axial cable open (Fig. 3): a) A transmitter sends a high frequency wave into a co-axial cable.
A pulsing electrical field is created File Size: KB. For this purpose, the paper discusses the development process of electric performance compensation methods for radio telescopes, presents the characteristics of large antennas with the application of the active surface adjustment, summarizes the key active adjustment technologies, compares typical large antennas using active adjustment for the antenna main reflectors, and.
Analysis of Reflector Antennas provides information pertinent to the analysis of reflector-antenna systems. This book provides an understanding of how design data have been and can be derived. Organized into four chapters, this book begins with an overview of the history of focusing reflector-antenna systems characterized by a highly variable Book Edition: 1.
A reflectarray antenna (or just reflectarray) consists of an array of unit cells, illuminated by a feeding antenna (source of electromagnetic waves). The feeding antenna is usually a unit cells are usually backed by a ground plane, and the incident wave reflects off them towards the direction of the beam.A phase distribution of concentric rings is applied to focus the wavefronts from.
Antennas for Satellite Communications. The antenna is the most visible part of the satellite communicationon system. The antenna transmits and receives the modulated carrier signal at the radio frequency (RF) portion of the electromagnetic spectrum.
For satellite communication, the frequencies range from about GHz (VHF) to 30 GHz (Ka-band. This shape forms the reflective surface in the antenna that enables waves reflected by the surface to retain their phase relationship, thereby enabling the maximum gain to be obtained.
In other words, RF energy in the form of electromagnetic waves travelling towards the antenna in a plane wavefront will be reflected by the reflector and remain.
3. Dual-reflector antennas The dual-reflector antenna consists of two reflectors and a feed antenna. The feed is conveniently located at the apex of the main reflector. This makes the system mechanically robust, the transmission lines are shorter and easier to construct (especially in.
Metamaterial antennas are a class of antennas which use metamaterials to increase performance of miniaturized (electrically small) antenna systems. Their purpose, as with any electromagnetic antenna, is to launch energy into free space. However, this class of antenna incorporates metamaterials, which are materials engineered with novel, often microscopic, structures to produce unusual physical.
Effects of surface RMS on antenna pattern Depending on the desired sidelobe envelope, surface RMS better than wavelength/50 (for reflector antennas) and wavelength/25 (for array antennas) may be required. No distortion Wavelength/50 distortion Reflector Design Options Symmetric Parabolic Spherical Torus Others Offset Parabolic Cost TechnologyFile Size: 4MB.
—More information on System overview on electromagnetic compensation for reflector antenna surface distortion (SuDoc NAS ) NASA, " System architecture of MMIC-based large aperture arrays for space applications (SuDoc NAS ) ". Double reflector antennas Double reflector antennas offer additional flexibility.
The sub-reflector viewing angle may be differ from the main reflector viewing angle and the equivalent f/D ratio may differ from that of the main reflector. However they have higher losses and a higher mass. Also their scan capability is limited.
Sub-reflector. a framework for understanding practical antennas that are useful. Many design issues are covered, but in many cases the “cookbook” designs oﬀered in this book are good-enough starting points, but still nonoptimal designs, only achievable by simulation, and testing.
As a result, the book places a fair amount of emphasis on antenna File Size: 1MB. Reflector antenna analysis and design (IEE electromagnetic waves series) [Wood, P.
J] on *FREE* shipping on qualifying offers. Reflector antenna analysis and design (IEE electromagnetic waves series)Author: P. J Wood.Deformation and Vibration of Conformal Antenna Arrays and Compensation Techniques influence on the antenna system.
The present paper gives an overview over different tools for the electromagnetic modelling and design of The distortion of the antenna surface may influence the antenna's .Type of system that increases an antenna's directivity by reflecting the electromagnetic waves off of various paraboloid-shaped reflectors.
Quasi-Optical Reflectors Proper wave propagation path for.