@article {05_IJRFMiCAE_Ruiz-CruzRebollar_Eigenmodesofwaveguides, title = {Eigenmodes of waveguides using a boundary contour mode-matching method with an FFT scheme}, journal = {International Journal of RF and Microwave Computer-Aided Engineering}, volume = {15}, number = {3}, year = {2005}, month = {May}, pages = {286-295}, abstract = {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}, keywords = {boundary contour mode-matching method, eigenmodes, FFT}, issn = {1096-4290}, doi = {10.1002/mmce.20082}, url = {http://www3.interscience.wiley.com/cgi-bin/fulltext/110429941/PDFSTART}, author = {J A Ruiz-Cruz and Rebollar, J M} } @conference {03_APS_Ruiz-CruzRebollar_BCMManalysisof, title = {BCMM analysis of short-slot waveguide couplers with an FFT algorithm}, booktitle = {Proc. 2003 IEEE Antennas and Propagation Society International Symposium}, volume = {2}, year = {2003}, month = {June}, pages = {1193-1196}, abstract = {In this contribution, the analysis of the short-slot directional waveguide couplers by means of a boundary contour mode-matching method (BCMM method) is presented. A new formulation is proposed that uses the FFT to improve the efficiency of the technique. The advantages and difficulties of the application of the BCMM for solving this kind of structure are also discussed. Simulated results are compared with those obtained by other numerical techniques. Experimental measurements are shown.}, keywords = {BCMM method, boundary contour mode-matching method, boundary-value problems, fast Fourier transforms, FFT algorithm, measurements, mode matching, numerical techniques, short-slot directional waveguide couplers, short-slot waveguide couplers, slot lines, waveguide couplers BCMM analysis}, issn = {0-7803-7846-6}, doi = {10.1109/APS.2003.1219449}, url = {http://ieeexplore.ieee.org/iel5/8636/27400/01219449.pdf?tp=\&isnumber=\&arnumber=1219449}, author = {J A Ruiz-Cruz and Rebollar, J M} } @article {03_IEEPMAP_Ruiz-CruzEstebanRebollar_Efficientboundarycontour, title = {Efficient boundary contour mode-matching method of H- and E-plane junctions by fast Fourier transform algorithm}, journal = {IEE Proceedings Microwaves, Antennas and Propagation}, volume = {150}, number = {5}, year = {2003}, month = {Oct.}, pages = {332-338}, abstract = {An efficient boundary contour mode-matching method (BCMM) is applied to the analysis of H- and E-plane junctions with planar and circular boundaries. The proposed approach is based on the use of the fast Fourier transform (FFT) to improve an analytical BCMM method. The electromagnetic field inside the structure is expressed in terms of circular waves, whereas in the rectangular ports a modal expansion is used. Depending on the shape of the contour, the original field expansion is rewritten in plane waves or in other sets of circular waves, replacing the conventional numerical integrations by a new, more suitable procedure. Finally, the transformation between the different expansions is carried out by means of the FFT, increasing notably the efficiency of the method. The presented formulation is verified by comparing simulated results with those obtained by other numerical techniques}, keywords = {boundary contour mode-matching method, circular boundary, circular waves, coupling integrals, efficient method, electromagnetic field, electromagnetic fields, fast Fourier transform algorithm, fast Fourier transforms, FFT algorithm, field expansion, fullwave analysis, H-plane junctions, junction matrix, mode matching, planar boundary, plane waves, simulated results, waveguide junctions E-plane junctions}, issn = {1350-2417}, doi = {10.1049/ip-map:20030775}, url = {http://ieeexplore.ieee.org/iel5/2196/28221/01262347.pdf?tp=\&isnumber=\&arnumber=1262347}, author = {J A Ruiz-Cruz and Esteban,J and Rebollar, J M} }