@conference {05_URSIUSA_Ruiz-CruzGentiliRebollar_Analysisofwaveguide,
	title = {Analysis of waveguide junctions by the Boundary Contour Mode-Matching Method with segmented regions},
	booktitle = {Proc. 2005 USNC/URSI National Radio Science Meeting},
	year = {2005},
	month = {July},
	pages = {1},
	abstract = {The Boundary Contour Mode-Matching method (BCMM) allows the analysis of homogeneous waveguide junctions. The basic building block of this method is an E- or H-plane structure with arbitrary contour, excited by several rectangular waveguides (the ports). The electromagnetic field inside the junction is expanded in basic solutions of the Maxwell equations as, for instance, circular waves (J.M Reiter et al., IEEE TMTT, 796-801, April 1995). In the ports, a modal series is used. The boundary conditions are imposed by means of a Galerkin method that relates the two different field expansions and leads to the Generalized Scattering Matrix (GSM) of the junction. Different improvements have been made to the method as (R. H MacPhie et al., IEEE TMTT, 232-237, Feb. 1999) and (J A Ruiz-Cruz et. al, IEE Microw. Ant. and Prop., 332-338, Oct. 2003), oriented to speed up the computation of the Galerkin method matrices. The technique has been successfully applied to different types of structures as arbitrary bends (circular, mitered,..), cavities with rounded corners and Y-junctions. In comparison with other quasi-analytical methods, this technique does not require to characterize the eigenfunctions of the junction. However, when ridged zones appear in the contour of the problem (for instance a bend with a matching element), the BCMM linear system is not well conditioned and convergent results are difficult to achieve. The aim of this contribution is to overcome the limitations of the ridged zones by means of segmenting the junction under analysis in regions which can be successfully analyzed by the BCMM. The trivial case is when the problem can be divided in two or more basic building blocks linked by waveguide ports, which can be solved by cascading the GSM of each separate block. This contribution will focus on structures, like a T-junction with an inner ridge zone, where the trivial case can not be applied and the segmented regions must be considered all together in the field-matching procedure. The formulation will use three type of expansions: a) a dedicated expansion for representing the electromagnetic field in each segmented region, b) the modal series in the ports, c) a series to describe the electric field at the interface between regions. All the amplitudes of the expansions are linked by the boundary conditions at the interfaces. A Galerkin method will provide the GSM of the junction. The results of the investigated problems will be shown in the oral presentation.},
	author = {J A Ruiz-Cruz and Gentili, G G and Rebollar, J M}
}
@article {04_WSEAS_Ruiz-CruzMontejo-GaraiRebollar_Applicationofsimulated,
	title = {Application of the simulated annealing for waveguide filters with complicated frequency response},
	journal = {WSEAS Transactions on Mathematics},
	volume = {3},
	number = {4},
	year = {2004},
	note = {Acceptance Rate = (Number of Accepted Papers) / (Number of Submitted Papers) *100 = 13.45\%, SCImago: 0.039},
	month = {Oct.},
	pages = {807-812},
	abstract = {A design approach for microwave waveguide filters with complicated response is proposed. It uses a combination of analytical filter synthesis theory, a very efficient"fullwave" analysis method of the structure and the Simulated Annealing (SA) optimization algorithm. Instead of a single optimization of the whole structure, the knowledge of the analytical synthesis of the filter allows todivide the optimization into more straightforward partial problems. In this way, the filter is segmented into sections that are optimized to match the partial frequency responses obtained from the analytical synthesis procedure. These optimized sections are a very useful starting point to overcome the difficulties of the final optimization of the whole structure. These ideas areapplied to the design of two waveguide filters with sophisticated response. The obtained results show the efficiency of the presented approach.},
	keywords = {microwave waveguide filters, optimization, simulated annealing., synthesis theory},
	issn = {1109-2769},
	url = {http://www.worldses.org/journals/mathematics/mathematics-october2004.doc},
	author = {J A Ruiz-Cruz and Montejo-Garai, J R and Rebollar, J M}
}
@conference {03_URSIUSA_Ruiz-CruzRebollar_alternativeinterpretationof,
	title = {An alternative interpretation of resonance of two-aperture irises in rectangular waveguide},
	booktitle = {Proc. 2003 USNC/URSI National Radio Science Meeting},
	year = {2003},
	month = {June},
	pages = {226},
	abstract = {The multiple aperture irises present some interest for the design of low cost bandpass filters with some improved stopband attenuation. Approximate estimation of the rejection resonance position based on circuit theory modelling, joint to a circuital interpretation was proposed by (N G Paterson, Electron Lett, 592-594, 1976). An accurate electromagnetic estimation of such rejection resonance was presented at (R. Yang, IEEE Trans. MTT, 1369-1373, 1993). An interpretation of the nature of this resonance for two-aperture in terms of a pair of natural oscillations in the open-waveguide type structure was presented at (A A Kirilenko, IEEE Trans. MTT, 1419-1421, 2000). Application for a new type of bandstop filter with three-aperture irises was presented at (L. Mospan, VIII Int. Conf. MMET, 503-505, 2000). In this paper, we present and alternative interpretation of resonance of two-apertures iris in terms of the excitation of the TEM mode of the structure. The mentioned TEM mode considers the strip between the two irises as one conductor and the wide walls of rectangular waveguide as the second conductor of the transmission line. This transmission line is short-circuited at both ends and its total length is approximately the wide of the iris. An accurate fullwave electromagnetic simulation joint to a visualisation of the electric and magnetic field vectors in the structure are employed to discuss and validate this interpretation. We consider that this alternative interpretation is very simple and useful from the designer point of view, specially to prevent spurious resonance in a variety of devices that use the mentioned multi-aperture iris structure. Quantitative results of resonance frequency positions and field plots at these frequency points for different structures will be presented.},
	author = {J A Ruiz-Cruz and Rebollar, J M}
}
@conference {02_URSIESP_Ruiz-CruzRebollar_Analisisdeuniones,
	title = {An{\'a}lisis de uniones en gu{\'\i}a de onda plano E y H mediante el m{\'e}todo BCMM y el uso de la FFT},
	booktitle = {Proc. 2002 Simposium Nacional URSI (in Spanish)},
	year = {2002},
	month = {Sept.},
	pages = {519-520},
	abstract = {The 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, increasing notably the efficiency of the technique. The presented formulation is verified by comparing simulated results with those obtained by other numerical techniques.},
	url = {http://w3.iec.csic.es/ursi/articulos_alcalahenares_2002/sesiones/sesion6.pdf},
	author = {J A Ruiz-Cruz and Rebollar, J M}
}
