Eigenmodes of waveguides using a boundary contour mode-matching method with an FFT scheme
An efficient boundary contour mode-matching method (BCMM) is applied to the analysis of hollow waveguides whose cross section is enclosed by curved and planar boundaries. The TE and TM modes are expressed in terms of circular waves whose cutoff wavenumber and amplitudes are the unknowns of the problem.. The boundary conditions are imposed with a new line-integral extended over the closed contour. The weighting functions introduced and the use of the transformations between plane and circular waves avoid the conventional numerical integrations. In addition, the conversion between the different field representations is accelerated due to the use of the fast Fourier transform (FFT). Finally, the numerical results are shown as a comparison of our approach with other numerical methods. (c) 2005 Wiley Periodicals, Inc.
eigenmodes boundary contour mode-matching method fft