Caracterización modal de guías arbitrarias y aplicación a dispositivos de microondas

En esta tesis se desarrollan una serie de técnicas de análisis y diseño de dispositivos de microondas que harán hincapié en la necesidad de precisión y eficiencia en los mencionados procesos tanto para analizar como para diseñar dispositivos de microondas que se describirán de manera exhaustiva en la tesis. A su vez, se desarrollan técnicas de aceleración de algoritmos de análisis que reducen en gran medida el tiempo de caracterización de estructuras que componen los dispositivos. Debido a la complejidad de los dispositivos actuales, un incremento en la velocidad de análisis mejora a su vez los tiempos requeridos para el diseño y desarrollo de estos complejos dispositivos. Esto es debido a que las técnicas CAD requieren algoritmos de optimización que invocan a los módulos de análisis repetidas veces. Este objetivo de aumento de velocidad y precisión en el análisis y diseño ha requerido una cuidadosa elección de técnicas así como una profunda mejora de las mismas.Cogollos Borras, S. (2002). Caracterización modal de guías arbitrarias y aplicación a dispositivos de microondas [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/5081Palanci

Distributed Models for Filter Synthesis

The limitations of filter synthesis methods based on classic equivalent circuits with the enhanced distributed models and synthesis procedures able to overcome such limitations are presented. A modified procedure that corrects the waveguide lengths has been proposed. The input and output reflection coefficients of the ideal prototype steps are real. The shunt capacitive effect introduces a phase shift in the reflection coefficients of each waveguide step. The representation of the filter structure can be improved if the waveguide steps are analyzed with a full-wave electromagnetic (EM) simulator, and their responses are stored in the form of ABCD matrices. The desired filter passband cutoff frequency was 11 GHz, with a specified return loss of 25 dB, and a gap height greater than 4.25 mm. High-power applications with wide stopbands often require impractical waveguide sections. The accurate EM simulators are used to find an almost exact equivalence between the prototype and the filter parts.Boria Esbert, VE.; Soto Pacheco, P.; Cogollos Borras, S. (2011). Distributed Models for Filter Synthesis. IEEE Microwave Magazine. 12(6):87-100. doi:10.1109/MMM.2011.942010S8710012

Design of compensated multiport waveguide junctions considering mechanization effects

tA new tool for the rigorous and efficient design of compensated multiport waveguide junctions, consider-ing the mechanization effects due to low-cost manufacture techniques, is presented. Several new designsfor a great variety of key components, present in modern microwave and millimetre-wave equipment, areproposed taking into account the introduction of rounded corners in the rectangular waveguide accessports. The new implemented tool permits to control and compensate for the potential degradation of thewide-band performance of such components prior to their fabrication, thus achieving an optimal design.All the presented results have been successfully validated by comparing the obtained simulated datawith the results provided by a commercial software based on the finite-element method.San Blas Oltra, ÁA.; Boria Esbert, VE.; Gimeno Martinez, B.; Cogollos Borras, S. (2015). Design of compensated multiport waveguide junctions considering mechanization effects. AEU - International Journal of Electronics and Communications. 69(1):328-331. doi:10.1016/j.aeue.2014.10.003S32833169

Efficient full-wave modal analysis of waveguides with arbitrary geometry defined by straight, circular and elliptical segments

Many modern waveguide devices, such as dual-mode filters and diplexers, can be modelled considering the whole circuit as a cascade of waveguide step discontinuities. Most of such discontinuities usually involve waveguides with arbitrary cross-section defined by linear, circular and/or elliptical segments. A fast and accurate procedure for the full-wave modal characterization of such arbitrarily shaped waveguides is based on the Boundary Integral— Resonant Mode Expansion (BI-RME) technique well described in [1]. In this paper, we present a very efficient implementation of a full-wave modal analysis tool for arbitrarily shaped waveguides based on the BI-RME theory.This work was supported by the European Commission under the Research and Training Networks Programme, Contract No. HPRN-CT-2000-00043

Efficient coupling integrals computation of waveguide step discontinuities using BI-RME and Nyström methods

This paper describes a novel technique for the very efficient and accurate computation of the coupling integrals of waveguide step discontinuities between arbitrary cross section waveguides. This new technique relies on solving the Integral Equation (IE) that provides the well-known Boundary Integral - Resonant Mode Expansion (Bi-RME) method by the Nystrom approach, instead of using the traditional Galerkin version of the Method of Moments (MoM), thus providing large savings on computational costs. Comparative benchmarks between the results provided by the new technique and the original BI-RME method are successfully presented

Efficient Design of Waveguide Manifold Multiplexers Based on Low-Order EM Distributed Models

In this paper, a new systematic technique to design manifold-coupled multiplexers in waveguide technology is proposed. The new technique uses generalized low-order electromagnetic (EM) distributed models, which constitute a half-way point between the fast, but imprecise, analytical models, and the more accurate, but costly, full-wave EM models. The method can be applied to contiguous and noncontiguous channel multiplexers, in both E-plane or H-plane configurations. This paper covers the complete design procedure for manifold multiplexers, starting from the required specifications and finishing with the physical dimensions. After explaining the general design technique for multiplexers with channel filters based on transmission-line resonators, the method is specialized for the design of classic multiplexers with circular-waveguide dual-mode filters. As a further application example, the same methodology is also used for the design of a nonconventional tuningless wideband multiplexer with a new type of rectangular waveguide filters. This paper is concluded with a comparison between simulation and measurements for the wideband multiplexer. Excellent agreement between measurements and simulations are demonstrated, thereby validating the complete design procedure.The authors would like to thank the European Space Agency (ESA) and Val Space Consortium (VSC) High Power RF Space Laboratory (A laboratory funded by the European Regional Development Fund, A way of making Europe) for financing the manufacture and experimental validation of the wideband six-channel PIM test bed.Cogollos Borras, S.; Soto Pacheco, P.; Boria Esbert, VE.; Guglielmi, M.; Brumos Vicente, M.; Gimeno Martinez, B.; Raboso García-Baquero, D. (2015). Efficient Design of Waveguide Manifold Multiplexers Based on Low-Order EM Distributed Models. IEEE Transactions on Microwave Theory and Techniques. 63(8):2540-2549. doi:10.1109/TMTT.2015.2442990S2540254963

FUNDAMENTOS DE LA TEORÍA DE FILTROS

Los canales de comunicaciones son el medio básico de transmisión de la información y seleccionar un canal o un grupo de ellos se realiza a través de filtros.El libro pretende ser un texto básico de diseño de filtros pero haciendo hincapié en los conceptos y desarrollos y no en las fórmulas finales. En la industria se utilizan recetas prácticas para el diseño de filtros y la mayoría de ingenieros usan las recetas sin conocimiento de su procedencia y sus limitaciones.Este libro enfatiza en los primeros capítulos las fórmulas ideales de los filtros desde el punto de vista matemático.En capítulos posteriores se traduce la función matemática en un circuito de forma lógica y argumentada para posteriormente aplicar el diseño a filtros de radiofrecuencia y microondas. A lo largo del libro se han introducido notas históricas que permiten al lector seguir la obra de los pioneros en este campo.Cogollos Borras, S. (2016). FUNDAMENTOS DE LA TEORÍA DE FILTROS. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/64546EDITORIA

Efficient CAD tool of complex passive devices composed of arbitrarily shaped waveguides using Nyström and BI-RME methods

This paper presents a novel CAD tool for the complete characterization of complex passive microwave devices in waveguide technology. The analysis is based on an Integral Equation (E)tec hnique that provides a very efficient characterization of discontinuities between waveguides with an arbitrary cross-section composed of linear, circular and elliptical am. The modal analysis of such waveguides is based on a modified version of the well-known Boundary Integral - Resonant Mode Expansion BI-RME) method using the Nystrom approach, instead of using the traditional Galerkin version of the Method of Moments (MOM), thus providing significant savings on computational costs. Previous results concerning this Nystrom BI-RME approach only compared the loss of accuracy in computing the modal spectrum of arbitrary waveguides. In this work, new comparative benchmarks between the results provided by the new technique and the original BI-RME method are successfully presented for real complex passive waveguide devices

CAD of complex passive devices composed of arbitrarily shaped waveguides using Nyström and BI-RME methods

In this paper, a novel computer-aided design (CAD) tool of complex passive microwave devices in waveguide technology is proposed. Such a tool is based on a very efficient integral-equation analysis technique that provides a full-wave characterization of discontinuities between arbitrarily shaped waveguides defined by linear, circular, and/or elliptical arcs. For solving the modal analysis of such arbitrary waveguides, a modified version of the well-known boundary integral-resonant-mode expansion (BI-RME) method using the Nyström approach, instead of the traditional Galerkin version of the method of moments, is proposed, thus providing significant savings on computational costs and implementation complexity. The novel theoretical aspects of this Nyström approach, as well as their impact on the original BI-RME formulation, are fully described. Comparative benchmarks between this new technique and the classical BI-RME formulation using Galerkin are successfully presented for the full-wave analysis of frequently used irises (i.e., rectangular cross-shaped and circular multiridged) and for the CAD of complex waveguide components (such as rectangular waveguide filters considering mechanization effects and dual-mode circular waveguide filters with elliptical irises).This work was supported by the Ministerio de Ciencia y Tecnología, Spanish Government, under the Special Action of Space National Plan ESP2001-4547-PE

Efficient full wave modal analysis of arbitrarily shaped waveguides using BI-RME and Nyström methods

This paper describes a novel technique for the very efficient and accurate full-wave modal analysis of cylindrical waveguides with arbitrary cross-section. This new technique relies on solving the integral equations that provide the well-known Boundary Integral - Resonant Mode Expansion (BI-RME) method by the Nyström approach, instead of using the traditional Galerkin version of the Method of Moments (MoM), thus providing large savings on computational costs. Accuracy aspects of this simple and fast procedure, which are directly connected to the rigorous treatment of the singular behaviour of the integral equation kernels, are carefully considered for waveguides defined by straight, circular and/or elliptical arcs. Comparative benchmarks between the new technique and the original BI-RME method are successfully presented for single- and multi-ridged waveguides, elliptical waveguides and rectangular waveguides with rounded corners