Fuyao Xie

Solution of Two-Dimensional Laplace Equation By Multipole Theory Method

A new approach, the multipole theory (MT) method, is presented for calculating two-dimensional (2-D) Laplace equation boundary-value problem. By the mathematical deduction, the generalized MT series formula and its applied laws are derived. The numerical analysis procedure and application of the MT method in electromagnetic engineering have been discussed. In order to verify the accuracy of this method, the MT method is applied to calculate the characteristic impedances of transmission lines of various cross-section configurations. The results obtained by the MT method are compared with exact data reported in the literature. It has been proven that the MT method is an effective approach for calculating 2-D Laplace equation boundary-value problems.

Multipole theory analysis of cutoff wavenumbers of waveguides partially filled with dielectric

A new approach, the multipole theory (MT) method, is presented for the computation of cutoff wavenumbers of waveguides partially filled with dielectric. The MT formulation of the eigenvalue problem of an inhomogeneous waveguide is derived. Representative computational examples, including dielectric -rod-loaded rectangular and double -ridged waveguides, are given to validate the theory, and to demonstrate the degree of its efficiency.

HYBRID CT-BEM METHOD ANALYSIS OF UNSCREENED SLAB LINES

A hybrid method of boundary element method (BEM) combined with conformal transformation (CT) is presented to calculate the capacitance of the unscreened slab lines. Conformal transformation transforms the infinite boundary boundary-value problem with the unscreened slab line into a finite boundary one that can be solved by the BEM, then the capacitance of the unscreened slab line is obtained by the BEM. Three representative computational examples, unscreened cylindrical single-bar slab line, unscreened rectangular single-bar slab line and unscreened cylindrical-bar coupled slab line, are given to validate the accuracy and efficiency of the CT-BEM hybrid method.

Multipole theory solution of two-dimensional unbounded eddy current problems

A new approach, the multipole theory (MT) method, is presented for the computation of two-dimensional (2D) unbounded eddy current problems. The essential concept is to represent the solution of the governing partial differential equation by the generalized MT formulae of the 2D Helmholtz equation and the 2D Laplace equation. The least squares method reduces the problem to the solution of a set of linear equations. Amperes law, as an additional constraint, is used to guarantee that the total net current is not changed due to the induced fields, and the radiation boundary conditions are satisfied. The eddy current problems of elliptic conductor, square conductor and a pair of circular conductors are considered as examples. The results obtained by the MT method are compared with experimental results and previously published work. It is shown that the MT method is an effective approach for computation of 2D unbounded eddy current problems.

FD-TD analysis of bandwidth characteristics in the asymmetrical ridge rectangular waveguide

The finite-difference time-domain (FDTD) method is applied to analyzing the influence of the ridge position on the cutoff wavelength and bandwidth of the dominant mode in the ridge waveguide. The cutoff wavelength and bandwidth of the dominant mode of the asymmetrical single- and double-ridge rectangular waveguide have been analyzed. Numerical results demonstrate that FD-TD method is precise and efficient, and the cutoff wavelength and bandwidth can be adjusted by changing the ridge dimensions as well as by adjusting its position.

Multipole Theory Analysis of Te0 and Tm0 Modes in Dielectric Loaded Cylindrical Cavity

This paper approaches the problem of calculating, by the multipole theory (MT) method, the resonant frequencies of TE0 and TM0 modes in cylindrical cavity axisymmetrically loaded with dielectrics. The MT formulation of eigenvalue problem of the partially homogeneous cavity is derived. The MT method is tested for accuracy by comparing numerically calculated the resonant frequencies against those analytically obtained for a cavity dielectrically loaded at its base. Furthermore, the MT method is applied to calculating the resonant frequencies of the cylindrical cavities loaded with two dielectrics and a dielectric rod, the numerical results are compared with the experimental data and the exact results reported in the literature.