Analysis of metallic antennas and scatterers:IEE ELECTROMAGNETIC WAVES SERIES 38
Series Editors: Professor P J. B. Clarricoats
Professor Y Rahmat-Samii
Professor J. R. Wait
Analysis of
metallic
antennas
and
scatterers
B D Popovič and
B M Kolundžija
Contents
Page
Preface x
1 Introduction 1
1.1 Basic concepts and definitions 1
1.2 Brief review of the method of moments 3
1.3 Basic integral equations for solving electromagnetic-field
problems 6
1.4 Short review of existing methods for the analysis of metallic
antennas and scatterers 8
1.4.1 Wire antennas and scatterers 9
1.4.2 Surface antennas and scatterers 11
1.4.3 Notes on numerical analysis of thin-wire and surface
antennas and scatterers 14
1.5 Conclusions 15
2 Modelling of geometry of metallic antennas and scatterers 16
2.1 Introduction 16
2.2 Generalised quadrilaterals 17
.2.2,1 Definition of generalised quadrilaterals 17
2.2.2 Some geometrical quantities important for approximation
of surface currents 19
2.3 Degenerate forms of generalised quadrilaterals 19
2.3.1 Generalised wires 19
2.3.2 Generalised triangles 21
2.3-3 Bodies of revolution and bodies of translation 21
2.4 Exact modelling of geometry by generalised quadrilaterals 22
2.5 Notes on approximate modelling of geometry 23
2.5.1 Introduction 23
2.5.2 Description of difference between approximate and actual
structures 25
2.5.3 The basic classes of shapes for geometrical modelling of
metallic antennas and scatterers 25
2.5.4 Surface-patch, wire-segment and wire-grid modelling 26
2.6 Approximate modelling of generalised wires 26
2.6.1 Approximation of wires by spline curves 26
2.6.2 Right truncated .cones 28
2.6.3 Piecewise-cylindrical approximation of wires 31
2.7 Approximate modelling of generalised quadrilaterals 33
2.7.1 Approximation of surfaces by spline quadrilaterals 33
2.7.2 Bilinear surfaces 34
..........................................................................................
Preface
Many articles and quite a few book chapters have been written on the numerical
analysis of metallic antennas and scatterers in the frequency domain. The major
points of these impressive contributions to our knowledge in numerical analysis
of electromagnetic fields can be summarised briefly as follows:
• Several types of integral equation have been used for the analysis. For specific
types of problem, some of them were claimed to be more convenient than the
others
• The equations have been solved numerically mainly by one of the three well
known moment-method procedures: point-matching, Galerkin or (in few
cases) least-squares
• Subdomain approximation has been adopted in most instances. Only
relatively few authors have preferred the entire-domain approach
• For the approximation of metallic surfaces, triangles have been adopted by
the majority of authors. A triangle is defined uniquely by three arbitrary
points in space so that any system of points over a conducting body can be
used to obtain an approximation of the body surface with triangles
• In the approximation of metallic wires, piecewise-cylindrical approximation
has been used almost without exception
• For both metallic surfaces and wires, the type of approximation of current
varied from the simplest subdomain pulse functions to entire-domain (or
almost-entire-domain) polynomials and/or trigonometric functions. Current
continuity from one surface or wire element to the other has been observed in
most cases
• The difficult problem of wire-to-plate junctions, with or without excitation at
the junction, has been treated in considerable detail, but has been solved only
for certain classes of junction.
This book describes a relatively simple general unified approach to the analysis
of metallic antennas and scatterers. The authors believe that the approach
enables the solution to be obtained of a much wider class of problems than with
any of the existing methods. In fact, most of the available methods can be
regarded to a certain extent as special cases of that elaborated in this book.
Briefly, the approach developed in the book is based on the following principal
steps:
(i) On the basis of existing knowledge and many numerical experiments, the
electric-field integral equation is adopted as the optimal starting point in
the analysis; only for closed bodies is the combined integral equation
adopted instead
(ii) On the basis of numerous numerical experiments and comparison with the
overall efficiency of the other two procedures, the Galerkin method has
been adopted as the optimal procedure for solving the integral equation
Preface xi
(iii) The entire-domain (or almost-entire-domain) approach has been adopted
rather than the subdomain approach, because it results in significantly
smaller system matrices. For this reason the authors have been advocates of
the entire-domain philosophy for over two decades
(iv) Generalised quadrilaterals and their special class, bilinear surfaces
(uniquely defined by four arbitrary points in space), are adopted for the
approximation of geometry of bodies. These surface elements can model
practically any surface more efficiently and with fewer and larger elements
than the triangles
(v) A unique treatment is introduced of noncylindrical forms that are always
associated with cylindrical segments of wires (such as various types of wire
ei;ds or changes in a wire's radius), This has been achieved by introducing
generalised wires, and in particular their special forms the truncated cones
(with conical or flat rings or discs as important degenerate forms), instead
of cylindrical wire segments. In addition, generalised wires are considered
as special cases of generalised quadrilaterals, so that plates and wires are
modelled with essentially the same tools
(vi) The entire-domain approximation for current is expressed in the same
co-ordinates as the surface elements over which it is assumed to exist. A
procedure is introduced for converting any set of basis functions into a new
set which automatically satisfies current continuity at all interconnections;
this helps to reduce the number of unknowns. The polynomial expansion is
adopted as the principal expansion. It has been used by the authors and
their colleagues for many years, and has been found to be both the simplest
and the most flexible
(vii) Finally, a procedure for treating the wire-to-plate-junction problem is
proposed which does not require any additional types of surface elements
or current expansions (so-called attachment modes), as do all previous
methods.
A few ,useful simple new techniques will also be found in the book. Of these, quite
interesting may be a theorem which enables the excitation located on the plate of
a wire-to-plate junction to be (approximately) transferred to the wire. This
simplifies considerably the analysis of wire-to-plate junctions with excitation.
However, the procedure of highly economical and very accurate numerical
integration of the integrals appearing in the solution may be found to be even
more versatile.
The authors hope that engineers, scientists and graduate students interested in
the analysis of electrically small and medium-sized metallic antennas and
scatterers will find in this book a very powerful tool that circumvents most
difficulties encountered in other available methods.
This book could hardly have been written without the many discussions
the authors had during the last decades with their colleagues at the
Department of Electrical Engineering of the University of Belgrade. The ideas
compressed in this book are certainly partly theirs, although they may not
have spelled them out explicitly. In that respect, the authors wish to express
their gratitude particularly to Prof. M. B. Dragovic and Prof. A. R.
Djordjevic.
A significant part of the basic ideas and a part of the examples have been
published during the last few years in the Proceedings of the Institution of Electrical
Engineers, Part H. The authors are grateful for the permission to use this material.
B.D.P.
B.M.K.
Belgrade
May 1994
这本书好象有中译本，B D 波波维奇也是比较有名的人物，只是在前南斯拉夫贝尔格莱德大学工作，所以关注的人不是很多
好书啊
:50bb谢谢楼主分享
Analysis of metallic antennas and scatterers: Analysis_of_Metallic_Antennas_and_Scatters.pdf
