Analysis and Synthesis of Wire Antennas (Electronic & Electrical Engineering Research Studies)

310 Pages·1982·9.15 MB·English

by  B.D. Popovic

Analysis and
Synthesis of
Wire Antennas
ELECTRONIC & ELECTRICAL ENGINEERING RESEARCH STUDIES
ANTENNAS SERIES
Series Editor: Professor J. R. James
The Royal Military College of Science, Shrivenham, Wiltshire, England
1. Flat Radiating Dipoles and Applications to Arrays
G. Dubost
2. Analysis and Synthesis of Wire Antennas
B. D. Popovic, M. B. Dragovic and A. R. Djordjevic
Analysis and
Synthesis of
Wire Antennas
B. D. Popovic, M. B. Dragovic and A. R. Djordjevic
Department of Electrical Engineering,
University of Belgrade, Yugoslavia
RESEARCH STUDIES PRESS
A DIVISION OF JOHN WILEY & SONS LTD
Chichester· New York· Brisbane· Toronto· Singapore
RESEARCH STUDIES PRESS
Editorial Office:
588 Station Road, Letchworth, Herts. SG6 3BE, England.
Copyright© 1982, by John Wiley & Sons Ltd.
All rights reserved.
No part of this book may be reproduced by any means,
nor transmitted, nor translated into a machine language
without the written permission of the publisher.
Library of Congress Cataloging in Publication Data:
Popovic, Branko D.
Analysis and synthesis of wire-antennas.
(Research studies on antennas series; 2)
Includes index.
1. Antennas (Electronics)
I. Dragovic, M. B. II. Djordjevic, A. R. Ill. Title
IV. Series
TK7871.6.P68 1982 621.38'.0283 82-11078
ISBN 0 471 90008 7
British Library Cataloguing in Publication Data:
Popvic, B. D.
Analysis and synthesis of wire~antennas.
-(Research studies on antennas series; 2)
1. Antennas (Electronics)
I. Title II. Dragovic, M. B. Ill. Djordjevic A. R.
IV. Series 621.3841'1 TK656.A6
ISBN 0 471 90008 7
Printed in Great Britain
Editorial Preface
Wire dipole antennas and arrays have been extensively analysed for
nearly a century yet a gulf has existed up until recently between the
theory and practice. This came about because the exact theories could
only be applied to the idealised geometries of dipoles and monopoles
while engineering applications embraced a multitude of radiating wire
configurations. The advent of computers promised to bridge this gulf
since, in principle, the numerical methods enable engineers to calcu
late any arbitrarily shaped wire radiator. This has not always been
achieved because computational techniques can introduce additional
problems which obscure the value of computers as a design tool for en
gineers. In contrast, this present monograph presents the reader with
an exhaustive computational treatment of wire antennas in their widest
sense and clearly demonstrates the excellent results that can be ob
tained both by the numerical analysis and the synthesis of such radiat
ing structures. A particularly interesting feature is the use of al
most-entire domain polynomial representations of current instead of va
rious sub domain basis function representations used elsewhere. Apart
from the advantages of computational economy it does question the need
for more complicated methods. The attention paid to the excitation re
gion behaviour and the careful construction of practical antennas are
some of the many notable aspects of the book that exhibit the sound
physical appreciation the authors have for their research. Professor
Popovic and his colleagues have a high international reputation for
their contributions to engineering electromagnetics and this book is a
vi
culmination of many years of research. The text characteristically
lays bare the essential de tails in an economic yet lucid manner and
will appeal to postgraduates, research scientists and engineers alike,
establishing beyond doubt that wire antennas can be designed by comput
er with confidence.
April 1982 J. R. JAMES
Preface
Thin-wire antennas, or similar antenna structures, were essentially
the only antennas used for radio-communication purposes from the dis
covery of electromagnetic radiation by H. Hertz in 1887 until about the
mid-thirties. At that time, utilization of higher frequencies made
possible the design of other antenna types of practically acceptable
sizes. However, wire antennas have remained in a wide use until today.
Analysis of wire antennas was first based on a sinusoidal approxima-
tion of current distribution along the wires. This approximation is
known to predict fairly accurately the antenna radiation pattern, but
it is usually quite insufficient for accurate determination of the an
tenna impedance. Although an integral equation for the current distri
bution along cylindrical wire dipoles was derived by H. E. Pocklington
1
as early as in 1897, a more accurate current distribution than sinuso
2
idal along such dipoles was first obtained by E. Hallen in 1937, who
calculated a few terms of a series solution to another integral equa
tion for current distribution along cylindrical antennas, which bears
his name. R. W. P. King added considerably to our knowledge of wire
antennas following, largely, Hallen's basic approach, culminating in
3
his classical monograph in 1956. About a decade later, wide usage
of high-speed digital computers changed radically the methods of wire
antenna analysis. In addition, it opened the door for recent computer
aided design (synthesis) of such antennas by means of optimization
1
The numbers refer to the List of References at the end of the mono
graph.
viii
methods. At the present time, with adequate precautions and clear in
sight into the physical and numerical aspects of the problem, computer
aided analysis and synthesis of wire-antenna structures of electrically
moderate sizes can be so accurate that experimental verification of the
results thus obtained can almost be regarded more as a matter of cus
tom than of necessity. Nevertheless, these powerful modern methods for
analysis and synthesis of wire-antenna structures do not seem to be
widely accepted and recognized by antenna design engineers. This is
due, at least partly, to the fact that the modern ideas and numerical
techniques underlying the analysis and, in particular, synthesis of
wire-antenna structures are for the most part still to be found in the
periodical literature. The present monograph, in which certain modern
methods for wire-antenna analysis and synthesis are presented concisely
and with the needs of design engineers and university educators in
mind, is intended to fill this gap to some extent.
Essentially, the monograph represents a summary of over-a-decade
long research activity on wire-antenna analysis and design at the Uni
versity of Belgrade, Yugoslavia. The aim adopted in the very beginning
was to develop accurate, but conceptually and computationally simple
methods for analysis and, in the final stage, synthesis of general
wire-antenna structures. It could be said that the aim has been large
ly reached, because in practically all cases which were considered
the theoretical results were found to be in excellent agreement with
experimental results, almost within the limits of experimental error.
The principal objective of this monograph is to present, in an orderly
and compact manner, the main results obtained at the University of
Belgrade concerning the analysis and synthesis of diverse wire-antenna
structures. Almost no attempt was made to present, discuss, compare
and evaluate various methods for solving the wire-antenna problem pro
posed by other authors; that would have been a task of exceptional com
plexity. However, considerable care was exercised to make the mono
graph as self-contained and complete as possible.
Although some aspects of wire-antenna structures are not treated in
the monograph explicitly (e.g., general wire-antenna arrays, antennas
ix
made of circular wires with abrupt change in diameter, or of non-cir
cular wires, etc.) , most of them can be analysed and/ or synthesized
using the simple and accurate theory presented in the book with rela
tively little additional effort. On the other hand, many useful the
oretical and experimental result"s (most often, coupled to each other)
are presented throughout the monograph, as well as some practical data
for design engineers, e.g. , accurate graphs of conductance and suscep
tance of vertical monopole antennas above conducting ground plane driv
en by coaxial lines of various sizes (Appendix 5) and of una t tenua ted
electric-field intensity of such antennas versus radiated power, their
thickness and height (Appendix 6). It is believed, therefore, that the
book might be of equal value to university professors, design engineers
and graduate students interested in wire-antenna structures.
The monograph is divided into two parts: antenna analysis and antenna
synthesis. The first part is devoted to the numerical determination
of current distribution along various unloaded and loaded wire antennas
in a vacuum or in homogeneous and inhomogeneous dielectric media (in
general, lossy), and to the analysis of excitation regions and of wire
junctions and ends. The second part constitutes an introduction to
modern computer-aided design of wire-antenna structures by means of
optimization methods.
Although much of the material, as presented, has not been published,
a substantial part of the monograph was written by adapting, to a
larger or smaller extent, articles published by the authors over the
years in various journals and conference proceedings. In connection
with this, the authors wish to express their sincere gratitude to the
Institution of Electrical Engineers for permission to use the material
published in the Proceedings IEE and in Electronics Letters, to the
Institution of Electronic and Radio Engineers for permission to use
the material published in The Radio and Electronic Engineer, and to
Springer-Verlag for permission to use the material published in the
Archiv fur Elektrotechnik.
During the years of work which made this monograph possible, the
authors had a permanent support from the Department of Electrical