1、 The Institute of Electrical and Electronics Engineers, Inc.345 East 47th Street, New York, NY 10017-2394, USACopyright 1998 by the Institute of Electrical and Electronics Engineers, Inc.All rights reserved. Published 1998. Printed in the United States of America.ISBN 0-7381-0223-7No part of this pu
2、blication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior written permission of the publisher.IEEE Std 211-1997(R2003)(Revision ofIEEE Std 211-1990)IEEE Standard Definitions of Terms for Radio Wave PropagationSponsorWave Propagation Standards Committe
3、eof theAntennas and Propagation SocietyReaffirmed 11 September 2003Approved 9 December 1997IEEE Standards BoardAbstract:Terms and definitions used in the context of electromagnetic wave propagation relatingto the fields of telecommunications, remote sensing, radio astronomy, optical waves, plasmawav
4、es, the ionosphere, the magnetosphere, and magnetohydrodynamic, acoustic, and electrostaticwaves are supplied.Keywords:electromagnetic wave propagation, terminologyIEEE Standardsdocuments are developed within the IEEE Societies and the Standards Coordinat-ing Committees of the IEEE Standards Board.
5、Members of the committees serve voluntarily andwithout compensation. They are not necessarily members of the Institute. The standards developedwithin IEEE represent a consensus of the broad expertise on the subject within the Institute as wellas those activities outside of IEEE that have expressed a
6、n interest in participating in the develop-ment of the standard.Use of an IEEE Standard is wholly voluntary. The existence of an IEEE Standard does not implythat there are no other ways to produce, test, measure, purchase, market, or provide other goods andservices related to the scope of the IEEE S
7、tandard. Furthermore, the viewpoint expressed at thetime a standard is approved and issued is subject to change brought about through developments inthe state of the art and comments received from users of the standard. Every IEEE Standard is sub-jected to review at least every ve years for revision
8、 or reafrmation. When a document is morethan ve years old and has not been reafrmed, it is reasonable to conclude that its contents,although still of some value, do not wholly reect the present state of the art. Users are cautioned tocheck to determine that they have the latest edition of any IEEE S
9、tandard.Comments for revision of IEEE Standards are welcome from any interested party, regardless ofmembership afliation with IEEE. Suggestions for changes in documents should be in the form of aproposed change of text, together with appropriate supporting comments.Interpretations: Occasionally ques
10、tions may arise regarding the meaning of portions of standards asthey relate to specic applications. When the need for interpretations is brought to the attention ofIEEE, the Institute will initiate action to prepare appropriate responses. Since IEEE Standards rep-resent a consensus of all concerned
11、 interests, it is important to ensure that any interpretation hasalso received the concurrence of a balance of interests. For this reason, IEEE and the members of itssocieties and Standards Coordinating Committees are not able to provide an instant response tointerpretation requests except in those
12、cases where the matter has previously received formalconsideration. Comments on standards and requests for interpretations should be addressed to:Secretary, IEEE Standards Board445 Hoes LaneP.O. Box 1331Piscataway, NJ 08855-1331USAAuthorization to photocopy portions of any individual standard for in
13、ternal or personal use isgranted by the Institute of Electrical and Electronics Engineers, Inc., provided that the appropriatefee is paid to Copyright Clearance Center. To arrange for payment of licensing fee, please contactCopyright Clearance Center, Customer Service, 222 Rosewood Drive, Danvers, M
14、A 01923 USA;(508) 750-8400. Permission to photocopy portions of any individual standard for educational class-room use can also be obtained through the Copyright Clearance Center.Note: Attention is called to the possibility that implementation of this standard mayrequire use of subject matter covere
15、d by patent rights. By publication of this standard,no position is taken with respect to the existence or validity of any patent rights inconnection therewith. The IEEE shall not be responsible for identifying patents forwhich a license may be required by an IEEE standard or for conducting inquiries
16、 intothe legal validity or scope of those patents that are brought to its attention.Copyright 1998 IEEE. All rights reserved.iiiIntroduction(This introduction is not part of IEEE Std 211-1997, IEEE Standard Denitions of Terms for Radio Wave Propagation.)This is the third revision of the original IEE
17、E Std 211-1969, following those of 1977 and 1990. It is indeedtrue, as noted in previous Forewords, that the need for revising a denitions standard transcends its publica-tion date and is essentially continuous. Therefore, as this standard goes to print, work on the fourth revisionis already in prog
18、ress, consisting of adding new terms, rening or deleting old ones, and improving the over-all consistency of the standard. This voluntary effort is carried out by the Wave Propagation Standards Com-mittee (WPSC) Subcommittee on Denitions, which meets once or twice a year at conferences sponsored byt
19、he IEEE Antennas and Propagation Society and occasionally at college campuses. Increasingly, the meet-ings have been replaced by e-mail, expanding the opportunity for international participation, although sub-stantial contributions also continue to be made on postcards. The chair of the Subcommittee
20、 presenting thisrevision is Wolfhard J. Vogel, who took the baton from George H. Hagn who in turn was preceded by chairsJohn M. Kelso, C. H. Liu, and Kurt Toman. Both George H. Hagn, the Subcommittee Chair responsible forthe second revision, and Walter A. (Bud) Flood, Chair of the WPSC during most o
21、f this revision cycle, havebeen extremely supportive of the current Subcommittee Chair, thus preserving the momentum of the revi-sion effort and adding greatly to its substance. The individuals with primary responsibility for this third revi-sion as well as those who contributed or made useful comme
22、nts are acknowledged below. An invitation isextended to the users of this standard to contribute to the fourth revision whenever they see deciencies orhave ideas for an improvement by communicating with the WPSC chair via e-mail toWolf_Vogelmail.utexas.edu.Within the IEEE, the work has been coordina
23、ted with the APS Antenna Standards Committee and the fol-lowing societies: EMC, COM, and Instrumentation and Measurements. It has also been coordinated withStudy Groups 1, 5, and 6 of the International Telecommunication Union (ITU-R) and the U. S. NationalBody of the International Electrotechnical C
24、ommission (IEC).The elds covered by this standard include the following where pertinent to electromagnetic wave propaga-tion: radio astronomy, optical waves, plasma waves, ionosphere, magnetosphere, and magnetohydrody-namic, acoustic, and electrostatic waves.This standard was prepared by the Wave Pr
25、opagation Standards Committee (WPSC) Subcommittee on De-nitions. The Subcommittee was composed of the following membership:Wolfhard J. Vogel,Chair*Immediate past ChairMajor contributions were made by:Useful comments were made by:Gary S. BrownWalter A. FloodGeorge H. Hagn*Warren L. StutzmanDavid Thie
26、lFawwaz UlabyJames R. WaitWeng Chew Robert D. HunsuckerWilliam A. LutherErnest K. SmithJulius GoldhirshKevin A. HughesAkira IshimaruHao LingGlenn S. SmithGlenn StumpffivCopyright 1998 IEEE. All rights reserved.The Wave Propagation Standards Committee (WPSC) of the IEEE Antennas and Propagation Socie
27、ty(IEEE-APS) balloted this standard and had the following membership at the time of approval:*Immediate past ChairWhen the IEEE Standards Board approved this standard on 9 December 1997, it had the followingmembership:Donald C. Loughry,ChairRichard J. Holleman,Vice ChairAndrew G. Salem,Secretary*Mem
28、ber EmeritusAlso included are the following nonvoting IEEE Standards Board liaisons:Satish K. AggarwalAlan H. CooksonKim BreitfelderIEEE Standards Project EditorGary S. BrownJohn F. CavanaghWarren L. FlockWalter A. Flood*George H. HagnMotohisa KandaErnest K. SmithGlenn S. SmithWarren S. StutzmanDavi
29、d ThielFawwaz UlabyWolfhard J. VogelJames R. WaitClyde R. CampStephen L. DiamondHarold E. EpsteinDonald C. FleckensteinJay Forster*Thomas F. GarrityDonald N. HeirmanJim IsaakBen C. JohnsonLowell JohnsonRobert KennellyE. G. Al KienerJoseph L. Koepnger*Stephen R. LambertLawrence V. McCallL. Bruce McCl
30、ungMarco W. MigliaroLouis-Franois PauGerald H. PetersonJohn W. PopeJose R. RamosRonald H. ReimerIngo RschJohn S. RyanChee Kiow TanHoward L. WolfmanCopyright 1998 IEEE. All rights reserved.1IEEE Standard Denitions of Terms for Radio Wave Propagationabsorption: The process of converting electromagneti
31、c energy to heat.absorption band: A band of frequencies for which a medium is considered to be absorbing.absorption coefcient ( ): (of a medium). The rate of decrease of power density of a wave per unit dis-tance, due to absorption. For a homogeneous medium with relative complex permittivity and the
32、 perme-ability of free space m0:whereis the free-space wavelengthexp(+jwt)is the time factorNote:For inhomogeneous media See also:extinction coefcient.absorption cross-section ( ): (of a lossy body). The ratio of power absorbed by the body, , to thepower density of an incident plane wave, :See also:
33、extinction cross-section.acoustic-gravity wave. In the atmosphere, a low-frequency wave whose restoring forces are compressional,gravitational, and buoyant.active sounding: The remote sensing of atmospheric or ionospheric parameters by transmission and recep-tion of radio signals.adiabatic atmospher
34、e of refraction: See:refractive index gradient.albedo: (A)In astronomy (where the sizes of the objects/surfaces are extremely large in comparison to awavelength), the ratio of the total radiation reected (scattered) from an object to the total incident power.(B)In transport theory or particle scatte
35、ring (where the size of the object is not extremely large), the ratio ofthe total scattering cross-section to the sum of the scattering and absorption cross-sections.kaerka4pIm erl0=l0saPaSisaPaSi=IEEEStd 211-1997 IEEE STANDARD DEFINITIONS OF TERMS2Copyright 1998 IEEE. All rights reserved.amplitude:
36、 The maximum or peak value of a periodically varying quantity. Note:Sometimes the term com-plex amplitude is used to denote a phasor. See also:magnitude.angel echoes: Radar returns caused by atmospheric inhomogeneities, refractive index discontinuities,insects, birds, or unknown sources. Note:Origin
37、ally, when some physical target could not be identiedthrough direct visual observation, echoes from such unknown causes were designated as angels. angle of arrival: (of a wave). The angle between the negative of the propagation vector and a referencedirection.angle of incidence: At a point on a surf
38、ace, the angle between the negative of the incident propagation vec-tor and the outward normal to this surface.angular frequency ( ): (of a sinusoidal wave). times the frequency. Synonym:radian frequency.angular power spectrum: Constituted bythe mean squared magnitudes of the plane wave spectrum of
39、anelectromagnetic eld as a function of the direction cosines and . Note:The angular power spec-trum and the mutual coherence function are Fourier transform pairs. See also:mutual coherence function.anisotropic medium: A medium that is not isotropic, i.e., whose constitutive parameters depend on thep
40、olarization and direction of wave propagation of the electric and magnetic elds.antenna temperature: The temperature of a blackbody that, when placed around a matched, loss-freeantenna similar to the actual antenna, produces the same available noise power, in a specied frequencyrange, as the actual
41、antenna in its normal electromagnetic environment. See also:blackbody.antipodal focusing: Ionospheric focusing sometimes observed in the vicinity of the antipodal point orregion.aperture averaging: The reduction in output signal variation when the size of the antenna is large comparedto the decorrel
42、ation distance of the incident eld across the aperture. Note:The beamwidth of the antenna ismuch smaller than the angular spectrum of the incoming wave. See also:angular spectrum.atmospheric radio duct: A layer in the atmosphere within which radio waves propagate with low attenua-tion.atmospherics:
43、Transient bursts of electromagnetic radiation arising from natural electrical disturbances inthe lower atmosphere. Notes:1. In the past, the term staticwas used to include atmospherics and other radionoise. The term sfericsis in current use. 2. Below 1Hz, noise is primarily of geomagnetic origin; ab
44、ove 1 Hzit is due to lightning.attenuation: (of an electromagnetic wave). The decrease in magnitude of a eld with distance or withchanges in the path in excess of the decrease due to a geometrical spreading factor. See also: spreading fac-tor.attenuation coefcient: See:attenuation constant.attenuati
45、on constant ( ): The magnitude of the attenuation vector. Synonym:attenuation coefcient.Seealso:propagation vector.attenuation vector ( ): The imaginary part of the propagation vector, . The attenuation vector points inthe direction of maximum decrease in magnitude. See also:propagation vector.w 2pk
46、xk kykaa kIEEEFOR RADIO WAVE PROPAGATION Std 211-1997Copyright 1998 IEEE. All rights reserved.3aurora: Collective name of optical, electrical, and magnetic phenomena, generally at high latitudes, result-ing from direct excitation of the upper atmosphere by energetic particles.auroral absorption: The
47、 increased attenuation of radio waves propagating through the D and E regions ofthe ionosphere when additional ionization is produced by precipitating charged particles usually associatedwith the visual aurora.auroral hiss: Audio-frequency electromagnetic noise associated with auroras.auroral oval:S
48、ee: auroral zone.auroral zone:An annular region situated between approximately 60and 70 geomagnetic latitude, north orsouth, in which auroras are frequently present. Synonym:auroral oval.backscatter: The scattering of waves back toward the source.backscatteringcross-section: See:monostatic cross-sec
49、tion.Beer-Lambert Law: Also called Beers Law or Bougers Law,this law, valid for discrete random media,relates the intensity of an electromagnetic wave at one point to the intensity at another point in the directionof propagation. The intensity decreases exponentially with distance and the attenuation coefcient is equalto the product of the concentration of particles and the extinction cross-section per particle. Consequently,the application of Beers Law is restricted to weakly scattering media.bistatic scattering coefcient: The sc
