Radio Antenna Engineering

567 Pages·1952·15.662 MB·German

Radio Antenna
Engineering
ED M U N D A. LA PO RT
Chief Bngi11eer, RCA I11tr:matio11ol J)frision
Radio Corporation o.f . \ 1nrl'ica
;:!,e1àor Jlcmbcr, l11stit11/c o.f Rodio Enginccrs
}'IRST EDITIOX
McGraw-Hill Book Company, lnc.
New York Toronto Lomlo11
I
1952 '\
RADIO ANTENNA ENGTNEERTNCT
Copyright, 19,52, by thc McGraw-Hill Book C'ornpnny, Ine. Printcd in thc
United Statcs of Arncri('a. Ali rights rcscn-cd. This book, or purts thcrcof,
uw:, not be rcproduecd in any form without permission of thc publishcrs.
Lihrnry of Congrcss Catalog Card Kumber: i>l-12G2-l
THE ~IAPLE PRESS COMPANY, YORK, PA.
Preface
Antenna engineering has dcvcloped into a highly spt'cializcd field of radio
engineering which in turn is subdividcd into many special hranchcs. This
treatise will deal with antennas macl_e of wircs, masts, and towers for fre
quencies up to about 30 megacycles. Antennas for higher frequencies are
nowadays factory-designed and factory-built, ancl the opcrating and plant
engineers are relieved of the design prohlems.
There is a vcry extensive experienre with antennas within our range of
interest, but unfortunately there is only a relatively small amount of pub
lished materia! on techniques. In contrast, there is a vast literature on
antenna ancl racliation theory. It is the purpose of this book to attempt,
to compile a sufficient amount of useful engineering information to enable
nonspecialists to handle many of the orclinary antenna problems that
arise in point-to-point, grouncl-to-air, and military communications, and
in broadcasting. Some of the more aclvanced antenna designs suggested
by very-high-frequency and ultrahigh-frequency techniqucs are includecl
because the day is approaching when these principles will have to be
applied at the lower frequencit's as the spcctrum conditions hecome more
clifficult.
Transmission lines are inseparahly related to antennas, so a chapter on
this subject is inclucled, together with a chapter on impedance-matching
networks.
An author of a book on techniques is confrontecl with many difficult
situations because he must try to convey a sense of juclgment in significant
values and wise compromise in the presence of the many empirica! condi
tions that surround each individua! problem. The successful solution of
an engineering prohlem involves many arbitrary decisions and is largely
a matter of persona! ingenuity and resourcefulness in applying sound elec-
-trical and mechanical principles. For that reason some of our statements
made in the discussion of the various topics should not be interpreted too
rigorously. Our intention has heen to provide a certain amount of guid
ing counsel for those who need it even though it was necessary to over
simplify to some 'extent.
There are three basic aspects of antenna engineering. The first per-
v
vi PREFACE
tain,; to radiation eharal'!Nist i,·s and i11(·lll(l(•,; ali mat \('l',; of thc dist rihu
tion of rndia11t 0110rgy in ,;pat'(' aronnd a11 a11tf'n11a system, a,; wcll a;.; the
current di:,;tributions that prod1wc tlte radiatiun pattern. Tltc sceond
1wrtai11s lo ant0rnw. eircuitry :md invoh·c,; such rnattcr8 a,; ,;elf- and
mutuai impcdances, cmTcnts, potentials, insulation, and freder sy,;terrrn
that will yidd the desirecl current distributions. Third thcrc is the strue
turnl engineering which has to do with ali the mcchanical details of sup
port,,, rigging, materials, strPngths, weights, hardware, asscmbly, adjusta
bility, stability, and maintenance. ,vhile each aspect must be separately
developcd, the final design mnst bo an integration of thc throo, with a
minimum of compromise ancl within reasonable economie limits.
The pnrposc of a tnrnsmitting antenna is to project"radiant encrgy over
a given wan' path in the most offef'ti,·e and economica! manner. Tho
purpose of a receiving antenna is to ahsorb a maximum po,ver from a
passing wave field, with the maximum exclusiou of noise and interfcring
signals. The transit of a wave fiold between the two clepcnds upon the
physics of wave propagation. The antenna enginecr must be famihar
with wave propagation to be ahlc to design antenna systems of maximum
effective11ess. ,vave propagation is a vast ancl complicateci statistica!
·subject, and for that reason t he space that r·an be devotod to the subjeC't
in this book is limitecl to tlw han·st essontiab. Sources of detailecl infor
mation are indicateci for refcrencc ancl study. It may be expectecl that
future developments in om knowledgo of propagation will have their
influence on future antenna design.
The design formula;, for thc various types of antennas are presentecl
without proof and may \Je regarclocl as rccipes. Their theory aml cleriva
tion may be found in tho literaturc, togcther wìth more completo informa
tion of a relateci nature. Also, many data cnrves and tables are taken
from recognized sources, aìthough these are sometimcs rearrnnged for
greater utility. Some of the information is from nnpublishod sources and
includes muoh originai materiai. The appendixes contain reference data
of generai use to the antenna ongineer.
The nomenclature used for bands of frequencies is based primarily 011
their propagation characteristics. These terms are also approximately in
accord with the nomenclature adoptecl by the International Telocom
munications Union at its Atlantic City confcrence in 1947. The use of
these broad terms has a brevity ancl convenience that is v~ry desirable in
writing and talking about frequencies, provided that one thinks about
them as having indistinct boundaries.
One must recognize rather large overlaps in the bancls of frequencies
propagatcd as fo,tecl, and the bands shown are indicativo only. They
blend grnclually from onc into thc othor, the amount ancl the extreme
ranges varying with tbc state of the ionosphere and ground oharacteristics.
PREFACE vii
The thrce fre<1uc11cy groupi11gs also roughly defirw thrce diffrrent classcs
of design tcchnique for antennas, and we havc takcn them up in this ordcr.
To a <:ertai11 cxtcnt, biglr-fr<>qucn<'Y drsign tP<'lrniqucs mar be applicd to
antennas uscd for optical propagation, but antennas for tlie frcqucncics
propagateci optically bccome stili anothcr class of teelrniqucs bascd on
rigid prefahricated structurcs.
I
Abbrevia- : .
Term ' , Approxnnate band Most useful propagation
tion
-----------· -- ---·-----~-~-- -~---- ·-----------------~-
Low frequency LF or lf Up to 500 kilocycles Ground waves
(long wave)
Medium frequency MF or mf 200-5,000 kilocyeles Both ground ami sky waves
(medium wave)
High frequency HF or hf 3--10 megacycles Sky waves propagatcd by way
(short wave) of the ionosphere
Wherever possibk we have used the meter-kilogram-sccond system of
units in the formulas. However, in a practical work of this nature it is
necessary to adhere to prevalent engineering usage of heterogeneous sys
tems of units. For example, in the Unitecl States it is standard engin~cr
ing practice in broaclcasting to base thc performance of an antenna on
millivolts per meter at 1 mile ancl to use concluctivities in the centimeter
gram-seconcl electromagnetic system of units. The genera! use of the
English system of measurements leacls abo to the frcqucnt use of such
units in formulas. To avoicl confusion, the particular units usecl are
explicitly given where necessary, even though this requires a certain
amount of repetition. This i~ clone so that one ran select ancl use an iso
lateci formula conveniently.
Nomenclature with respect to wave polarization follows the stanclard
ized usagc where the orientation of thc eìcctric vector of thc wave fic!d
with respcct to thc earth clefines thc polarization. Vertical pobrization
i:-- understoocl when the electric vector of the wave is norma! to the earth's
surface, ancl horizontal polarization when thc elcctric vector is parallel to
the earth. Intermecliate polarizations also exist.
Comprehensive bibliographies are given at thc end of each chapter, and
a more generai bibliography is given in Appendix I. The papers listed
are those which bave a definite reference value to the antenna engincer
when he is searching for fundamental information, experimental data,
and history of the art, as reported in originai researches. Collectively
they comprise many thousancls of pages of information that cannot pos-
. sibly be conclensed into any single volume. As one aclvanccs further ar~d
further in the antenna-engineering art, the necd for reference to these
originai sourccs becomes more pressing and the value of an extensive
bibliography bccomes evident.
PREFACE
tìupcrscript numbc•r:-; an· Wit'd i11 th(· \(•xt to i11di1·atc rd(•\·a11t :-;0111TPS of
information. Xumhcr,s undPr 1000 rclatr tu tlio:-w rcfen•11c(':-; liskd at thc
end of the parti1·ular d1apl<-r i11 \I lii..J1 tlH·y an· r·it('d. Hd<Tl'll('(':,; i11 tl1c
1000 sPriPs an· to be found i11 .\ppcndix 1.
Thc book .-111/cn11as by .J. D. hrausH"'~ is a uscful one for tho::;c dcsirous
uf bceomi11g familiar with thc throretirnl prill('iplrs of antrnnas. 1t i::; a
synthcsis of the latcst thcorics of rndiation from a11te11ni\s and thc mcth
ods for computing radiation pattcrns all(l impeclanccs, nnd rcduccs thc
nccd to rcfcr to thc largc numhcr of origina! rcscarch papcrs distrilmtccl
through thc litcraturc of many ycars.
I acknowlcclgc with thanks thc cn<·ouragcmcnt of J.,:cith Tlc11ncy, Ecli
tor-in-Chicf of Radio Engineering llcrndhoo/,·, who suggcstcd tlwt this book
be writtcn, at thc time hc recci,·cd t.hc man11script for thc chaptcr on
Antcnnas which appcars in thc Fourth Eclition of thc Ilarnlbook.
I am dcrply indcbtcd to many coworkcn, and associatcs, present and
past, for information ancl im;trnction on antenna tcclmology ancl wavc
propagation ovcr many ycar::;. Thcrc is a special clcbt of gratituclc to
acknowlcdgc to Dr. Georgc H. Brown, Phillip S: Cartcr, Clarence W.
Hanscll, and IIemy E. Hallborg of thc HCA Laborntorics Division for the
use of information from t hc·ir puhlishccl ami unpublishccl rcsc·ardws. I
exprcss rny gratitllClc to Holwrt, F. JloHz for earcfully revic\,·ing thc carly
rnanuseript and rnaking many valuablc suggrstions. Thc final rnanu
seript was again painstakingly frviewecl hy .J. D. Fahncstock, \\·hosc pro
fo;.-,:;ional editoria] cffmt has greatly improvcd thc stylc ami arrùngrmcnt.
Thc followin[>; men kindly contrihutcd some of the photographs showi11g
t·onstrnction dctails: H. F. Cuy of thc Xational Broaclcasting Compnny;
.J. L. Finch of HCs\ Communirntions, Inc.; II. B. Seabrook ami .J. B.
1ù1ox of thc HCA Vietar Cornpany, Ltd.; A. O. :\ustin, Barberton, Ohio;
Lt. n. Y. Carrn!l of thc n.oya! Cimarlian Nnvy; .J. A. Ouimcnt ami J. E.
Ila~·cs of thc Canadian Broadcasling Corpora ti on; J-Iarold Bishop of the
Hrit i,;]1 Broadeasting Corporation; E. J. \Vilkinson of thc .:-\ustralian Post
rnast cr-Gcncral 's Dcpartment; \Y. l\I. \Yitty, Dallas,· Texas. E. \V.
Ihvis of tbc l\fotual Broaclcasti11g Systcm eontributcd thc map rcpro
duccd in Appcndix VI II.
I acknowledge with sincere thanks the kindness of the following organi
zai ions which have gra11tcd thc right oi rcproduction of ccrtain figurcs
unrkr t hPir ('Opyrights: I nstitutc of Radio Enginrcrs; I nstitution of Elec
trical Enginccrs; Amalgamatcd \Yirelcss (s\nstralasia) Ltd.; Bis l\Iajesty's
B'tationery Office, London; :\leGraw-llill Puhlishing Company, Inc.; Mar
eoni's \Yirelcss Tclegraph Company, Ltd.; Iirntitution of Radio Enginccrs
(Australia).
EmrnNn A. LAPOR'l'
GLEN Rma1,, N. J.
J a111wry, Hl52
Contents
PREFACE V
INTRODUCTION
CHAPTER 1. LOW-FREQUENCY ANTENNAS 13
1.1 lntrocluction 13
1.2 Lo,1·-fre4uency-1rn ve Prnp:1ga tion 1· 1
1.3 Lcl\\·-frequcnry Antenna, 18
1.4 Fundamental Frcque1l(':,· of a Straiglit, liniform \'crtiC'al Hadi:dor 20
1.5 Radiation Eflìeicncy 21
1.6 Racli:1tion Hecist:rncc 23
1.7 Charactcristic Irnpcrlanee of a Y erti ca I Antenna. 27
1.8 Antenna Reactancc 29
1.9 Transmission Jhnch1·idth of a Lo11·-fn,quc1wy .\ntPnna . 36
1.10 :\Iultiplc Tuning . 38
1.11 Antenna Potentini 45
1.12 Lo\\·-frcqucncy Grounrl Systems 49
1.13 Low-frcqupncy DircctiYe Antennas 54
1.14 Hderencc Data on Certain Forms of Lm1·-frequen,·y Antcnnas 67
1.15 Structural Design 69
t LHAt' 1 tK 1.. MEDiUM-FREQUEt"CY BROADCAST A~~TE~~t-~AS. 77
2.1 HeYiew of tlie Dcvelopmcnt of Broacknst Antennas. 77
2.2 l'redietion of :'lledium-frequency Co,·eragc 83
2.3 Harliation Characteristics of a \'erticnl Racliator. 94
2.4 Impcdance of Uniform-cross-scction Yertical Hadiators. 111
2.5 Ground Rystems for Broadeast Antennas. 115
2.6 Bandwiclth of a Racliator 124
2.7 Input Impcclance to Each R~1cliator in n Directi,·c Array 128
2.8 Broadcast Antcnn:i's· on Buildings 139
2.9 Antenna Potcntial 141
2.10 Aircraft Obstruction Lighting for Tmrnr Rhdiators . 143
2.11 A Single Yertical Rarliator for Two Differcnt Freqnt'I]('ies . J.J-(i
2.12 Cenerai Equations for the Pattc;rns of :\Iultielem~nt Array,-; of Vertical
Radiators. 147
ix
X LUNltNI::>
2.13 Diredin• .\ntrnna 11·ith :\faximum C:ain fm T1rn H:1di:itors lii:~
2.14 DircctiH :\ntrnnas l·sing l'ucqual-ll('iglit ILidiator, 155
2.15 DirC'ctin· Antcnn:1s fur \\'ide Angles of Suppn•,-,ion ]5(j
2.16 Prnduci11g Sy111111dri('al :\lultiplc·-n11ll l'att,·11,- JG.s;
2.17 Parnllclugram Arrn)·s 171
2.18 Dircct Synt1H·sis uf an Array for Any Sv;1·ific·d :\zi mutl1:.J l'a 11 (•111. 174
2.19 Distortion of Ibdiation l'attcrns Clo,;(' to an Array. 176
2.20 Stahility of Dircetin.' Broadcast Arrays 176
2.21 Structural lktails 182
CHAPTER 3. HIGH-FREQUENCY ANTENNAS 195
3.1 Rcvic1Y uf High-frequcncy Antrnna Dcvelopmcnt 195
3.2 Iligh-frcqucncy Propagatiun 199
3.3 Farturs Affecting Signa! Intelligibility. 218
3.4 High-frequcncy Transmitting-statiun Sites 22G
3.5 High-frcqucncy Rcceiving-station Sitcs 230
3.6 Dcsi11:n of a Horizontal Half-wavc-dipolc Antenna Systcm. 232
3.7 Effcct of Off-ccntcr Feccl on Ra<liation Pattern of Dipolc 2-16
3.8 Band1Yidth of a Horizontal Hnlf-wavc Dipole 2--!6
3.9 Folclecl Dipolcs 250
3.10 Univcrsal Antennas 255
3.11 Simplc Dircctivc High-frcqucncy Antcnnas 257
3.12 Ve rti ca I Dirccfo·ity of Stackcd Horizontal Di po Ics 2Gl
3.13 Horizontal Dirccti\·ity of Lines of Cophascd Dipo!C's 267
3.14 Bcam Slcwing for Droadside Arrays 271
3.15 Hadiation l'attcrns for Dipolc Arrays. 274
3.16 Supprcssing Seconclary LobC's 276
3.17 Pmrcr Distrilmtion among the Half-1rn 1·c Dipolcs of an Array 290
3.18 Fcccling Powcr to Dipole Arrays Using Half-11a1·c :::ìpacings 293
3.19 Input Impeclance to Any Radia tor in an Ari'ay of Dipoles. 295
3.20 Fouricr Currc11t Distrilmtions 300
3.21 Long-wirc Antcnnas . 301
3.22 V Antcnnas 3ìì
3.23 IIorizontal Rhombic Antenna 315
3.24 Fishbonc Hccciving Antenna 339
3.25 Travcling-wnvc Antenna for Vertically Polarizccl Transmission 341
3.26 Construction of High-frcquency Antennas 343
CHAPTER 4. RADIO-FREQUENCY TRANSMISSION LlNES 366
4.1 Propagation of Raclio-frcqucncy Currents in Lincar Concluetors 366
4.2 Uscful Transmission-linc Configurations ancl Thcir Fonnulas 374
4.3 Transmission-linc Design for "'idc-frequcncy Band. 404
4.4 Transmission-line I mpcclanec-matching Teclmiqucs. 406
4.5 Network Equirnlcnb of Transmission-line Scctions. 425
4.6 Balanc('(I to Unbalanced Transformations 426