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ABSTRACT: Hybrid-mode propagation properties of multilayered and
multiconductor transmission lines are studied by using an efficient
vector finite element method (FEM) with high-order hybrid edge/nodal
triangular elements, which can give frequency-dependent propagation
constants directly. Characteristic impedances are also calculated from
the FEM field solutions employing a reciprocity-related definition and
taking the modal orthogonality into account. The numerical results of a
coupled microstrip line are compared with those of the boundary integral
equation technique, and good agreement is obtained. Also, a dual-plane
triple microstrip line is analyzed. The approach is found to be very
general and able to simultaneously handle different thicknesses and
widths of strip conductors. The flexibility of the approach is also
shown by including anisotropy in the dielectric substrates of such lines
IEEE Transactions on Microwave Theory and Techniques 03/1997; · 1.85 Impact Factor
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ABSTRACT: The vector finite element method with hybrid edge/nodal triangular
elements is extended for the analysis of lossy planar transmission
lines. In order to handle lossy conductor transmission lines, the
present approach includes the effect of finite conductivity of a lossy
area, and the dissipations in metallic conductors and dielectrics are
calculated directly by considering a complex permittivity for the lossy
region of interest. A propagation constant formulation is used in the
FEM, which avoids spurious solutions absolutely and can handle sharp
metal edges in inhomogeneous electromagnetic waveguides. Numerical
examples are computed for microstrip lines, finlines, and triplate strip
lines. The results obtained agree well with the earlier theoretical and
experimental results, and thus show the validity of the method. Also,
the current distributions on the lossy microstrip lines with finite
strip thickness and isotropic substrates are presented
IEEE Transactions on Microwave Theory and Techniques 11/1995; · 1.85 Impact Factor
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ABSTRACT: The finite element method (FEM) with the high-order
mixed-interpolation-type triangular element is used to solve the problem
of practical microstrip lines with arbitrary metallization cross
section. Analyses are carried out to produce the frequency
characteristics of propagation constant, characteristic impedance, and
attenuation constant of shielded microstrip lines with rectangular,
trapezoidal, and semi-trapezoidal strip cross sections. A comparison of
the numerical results with those of the existing results shows good
agreement and thus verifies the versatility of the FEM. Also, the
numerical results show the effects of the metallization cross sections
on the transmission properties and thus emphasize the importance of
considering the practical microstrip configurations in the design of
miniaturized MMICs
IEEE Transactions on Microwave Theory and Techniques 12/1994; · 1.85 Impact Factor
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ABSTRACT: A vector finite element method with the high-order
mixed-interpolation-type triangular elements is described for the
analysis of optical waveguiding problems. It is a combination of linear
edge elements for transverse components of the electric or magnetic
field and quadratic nodal elements for the axial one. The use of
mixed-interpolation-type elements provides a direct solution for
propagation constants and avoids spurious solutions. This approach can
yield more accurate results compared with the conventional approach
using the lowest order mixed-interpolation-type elements, namely,
constant edge elements and linear nodal elements. The accuracy of this
approach is investigated by calculating the propagation characteristics
of optical rib waveguides. Results obtained for both E<sup>x</sup> and E
<sup>y</sup> polarizations are validated using benchmark results
produced by established methods
Journal of Lightwave Technology 04/1994; · 2.78 Impact Factor
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ABSTRACT: A simple approach based on the scalar finite element method is
described for the evaluation of the effective index, modal field
profile, and far-field pattern of the guided mode of an optical rib
waveguide and of the coupling efficiency of a butt-joint structure of
two single-moded rib waveguides. Calculations are performed for several
different rib waveguide structures, and the accuracy of the present
approach is examined and assessed by comparing the results obtained with
the other existing methods
Optoelectronics [see also IEE Proceedings-Optoelectronics], IEE Proceedings J 05/1992;
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ABSTRACT: A combination of the finite-element and boundary-element methods
is proposed for the solution of arbitrarily shaped discontinuities in an
open dielectric slab waveguide. The discontinuity region is divided into
two regions. One is a finite region with arbitrary inhomogeneities, and
the other is a semi-infinite and homogeneous region. The finite-element
and boundary-element methods are applied to the former and the latter
regions, respectively. For uniform waveguide regions connected to
discontinuities, analytical solutions in which both the guided and the
radiated modes are taken into account are used. To show the validity and
usefulness of this approach, computed results are given for several
kinds of discontinuities, and the accuracy of the solutions is
investigated in detail
IEEE Transactions on Microwave Theory and Techniques 05/1989; · 1.85 Impact Factor
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ABSTRACT: A combined method, using the finite-element approach and the analytical approach, is described for the solution of arbitrarily shaped discontinuities in a dielectric slab waveguide. Both TE and TM mode incidences are treated. The method is based on replacing the unbounded configuration by a corresponding bounded structure. The validity of the method is confirmed by comparing numerical results for step discontinuities with other available results. Computed results are also presented for typical boundary deformations in optical fibres caused by a fusion splice.
Microwaves, Antennas and Propagation, IEE Proceedings H 03/1988;
