IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. MIT-29, NO. 10, OCTOBER 1981
1059
boundary condition EZ = O
Br(ro)=O=E,(ro) or J.(~~rO) =0. (76)
We consider now the case m =0. Comparing (64), (66),
(68), (71), (73), and (75) with (52)-(54) we find that the
latter solution corresponds to a superposition of the TE
parts’ of B, and B= and the TM part of Bq. We use,
however, only the last term giving from rBv = const for the
“mode” k= f)
r~l ( yr ) = const (77)
(corresponding to a waveguide with cross section r=const)
and for k= 1 (TMOI mode) we obtain
~~1(~~).osz=const
(78)
which describes the surfaces on which B,= Ew = O and into
which metallic walls may be inserted without disturbing the
field patterns.
[1]
[2]
[3]
[4]
REFERENCES
F. Cap and R. Deutsch, “Toroidal resonators for electromagnetic
waves;
IEEE Trans. Microwaue Theory Tech., vol. MTT-26, pp.
478-486, Jdy 1978.
_ “Toroidaf resonatorsfor electromagneticwavesfl LEEE
Trans.
Micro;ave Theo~ Tech., vol
MTT-28, pp. 70G703, July 1980.
J. Zagrodzinski,
J. Phys. A: Math. Gen. vol. 10, pp. 823-831, 1977.
F. Cap, “Some
remarks on toroidaf problems: Beitr. Plasmaphys.
vol.
18,no. 4, pp. 207–217, 1978.
[5]
[6]
[7]
[8]
J. Jager and B. Schnitzer, “Characteristic values of dominant modes
within an empty torus computed by mesh method,” Institut ftir
theoretische Physik, Technische Universitat Graz, Rep. ITPR-8001 1,
June 1980.
D. Nielsen,
“The calculation of electromagnetic field modes in
toroidat cavities of rectangular cross section; Inst. Plasma Research,
Stanford Univ., SU-IPR Rep. 647, Dec. 1975.
S. Przezdziecki, “TE and TM fields inorthogonat coordinate systemsj”
Bull. A cad. Pol. Sci. vol. 8, nr. 8,
pp. 429-436, 1960.
American Institute
of Physics Handbook, New York: McGraw-Hill,
various editions.
*
Ferdinand Cap was born in 1924 near Viema,
Austria. He ~tudied physics, mathematics, and
chemistry from 1942– 1946 at the University of
Vienna, Vienna, Austria.
He became a Lecturer at the University of
Innsbruck, Innsbruck, Austria, in 1949 after a
stay at the Zttrich Technical University. He was
promoted to Assistant Professor in 1955, Associ-
ate Professor with tenure in 1957, and Fnlf Pro-
fessor in 1960. In 1967 he was Guest Professor
for plasma physics in New York. In 1971 he
became a Senior Research Associate of NASA at Goddard SDace Center
and in 1979 he was a visitor at the Princeton Plasma Physics “Laboratory.
For 10 years he was Austria’s Scientific Representative at the UN in New
York. He has published more than 100 papers in physics and severat
textbooks about nuclear reactors and plasma physics.
Analysis and Design of TE1l-to-HE1l
Corrugated Cylindrical Waveguide Mode
Converters
GRAEME L. JAMES
A bstract— A theoretical parametric study is given of a TE ~l-to-HE II wavegnide) with the HE,1 mode in the balanced condition at ka = 2.9. The
mode converter consisting of a section of cytindricaf corrugated wavegnide
prdlcted resssfts are in very good agreement with experimental data.
with varying slot depth. The anatysis makes use of modat field-matching
“ tecluiaues to detersnine the scatter matrix of the mode converter from
I. INTRODUCTION
which we deduce its propagation properties. It is shown that a mode
converter consisting of only five slots achieves a return loss better than 30
I
N DESIGNING corrugated horns which use a section
dB over the band 2.7 <ka< 3.8 (where a is the intemaf radius of the
of cylindrical corrugated waveguide at the input, it is
necessary to study the transition from a smooth-walled
Manuscript received January 1, 1981; revised April 10, 1981.
cylindrical waveguide supporting the TE, ~ mode to a cor-
The author is with the Division of Radiophysics, CSIRO, P.O. Box 76,
rugated cylindrical waveguide where the HE ~, hybrid mode
Epping, N.S.W. 2121,Australia.
is supported. With the corrugated surface represented by
0018-9480/81 /1000- 1059$00.75 01981 IEEE