Abstracts - Dipartimento di Elettronica Applicata

Meta 2010 & FEM 2010 – Rome, 13-15 December 2010
A FEM Analysis of
Microwave Components for Oversized Waveguides
Silvio Ceccuzzi (1) , Simone Meschino (2) , F. Mirizzi (1) , L. Pajewski (2) , C. Ponti (2) ,
and G. Schettini (2)
(1) Associazione EURATOM-ENEA sulla Fusione, C.R. Frascati, P.O.Box 65, 00044
Frascati (Rome), Italy – E-mail: mirizzi@frascati.enea.it
(2) Roma Tre University, Department of Applied Electronics,
Rome, Italy – E-mail: s.meschino@unroma3.it
The present work has been developed within the frame of the EFDA task “HCD-08-
03-01: LH4IT, EU contribution to the ITER LHCD Development Plan”
The use of rectangular oversized waveguides in the Main Transmission Lines (MTLs)
of the Lower Hybrid Current Drive (LHCD) system of ITER, requires to investigate
the problem of bends [1, 2]. In this context, the principal specifications that
characterize the design of the bends are: a) to minimize the reflection of the
fundamental TE10 mode; b) to maximize the transmission of the fundamental TE10
mode; c) to minimize the coupling between the TE10 mode and other spurious modes
that propagate at 5 GHz.
This paper presents an overview about the bend options, and it compares the
performances of several curved frameworks analyzed by using the Finite Element
Method (FEM) commercial software, HFSS ® .
Simple circular trajectory curves are considered, varying the bending radius. The
design of such curves is quite simple but not much flexible, being the bending radius
the only parameter. More design flexibility can be achieved using a Mitre Bend
structure. It is of great interest to study this type of bends in terms of coupling, to
check the possible advantages.
Finally an innovative modified Mitre-Bend-trapezoidal-elements solution is proposed.
In particular, a preliminary performances comparison among those different
alternatives is presented.
References
[1] A. A. San Blas, B. Gimeno, V. E. Boria, H. Esteban, S. Cogollos e A. Coves, “A
Rigorous and efficient full-wave analysis of uniform bends in rectangular waveguide
under arbitrary incidence”, IEEE Trans. Microwave Theory Tech., 51, 397-405, 2003.
[2] L. Lewin, D. C. Chang, and E. F. Kuester, Electromagnetic Waves and Curved
Structures, London, U.K.: Peregrinus, 1977.
[3] S. Ceccuzi, S. Meschino, F. Mirizzi, L. Pajewski, S. Schettini, et al., “Bends in Oversized
Rectangular Waveguide,” Proc. of the 26 th Fusion Technology Symp., P1-045, Porto, Portugal,
Sept. 27- Oct. 1, 2010.
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