Publications (49)0.59 Total impact
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Article: Optimization-Oriented Design of RF/Microwave Circuits Using Inverse-Linear-Input Neuro-Fuzzy-Output Space Mapping With Two Different Dimensionality Simulators.
IEEE Trans. on Circuits and Systems. 01/2011; 58-I:176-185. -
Article: A full‐wave space‐domain method for the analysis of leaky‐wave modes in multilayered planar open parallel‐plate waveguides
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ABSTRACT: This work presents a novel numerical technique for the analysis of leaky-wave modes in laterally shielded, top-open multilayered planar transmission lines. The method develops the multilayered-media boxed Green's functions for this type of electromagnetic devices, and solves the characteristic electric-field integral equation (EFIE) by using the method of moments (MoM). The analytical expressions used for the computation of the kernel of this technique are derived in this article, and results for leaky-wave modes in different practical structures are presented. The strong analytical nature of the proposed approach allows for a low-cost computational code without losing its full-wave accuracy. Comparisons with previous works are presented, showing the advantages of this new method for the analysis and design of practical millimeter-band leaky-wave antennas. © 2004 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005.International Journal of RF and Microwave Computer-Aided Engineering 12/2004; 15(1):128 - 139. · 0.59 Impact Factor -
Article: Programa para analizar el transitorio de transferencia de energía electromagnética desde una fuente a una carga por una línea de transmisión
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ABSTRACT: This contribution presents a software which has been developed to make more visual and comprehensive the study of the electromagnetic propagation of RF waves in a transmission line. The propagation of voltage, current and power waves from a source system to a load, using a transmission line, is one of the most basics aspects that any student of electrical engineering must understand, and one of the most common scenarios presented in actual work with RF systems. The theory studied in subjects related with microwaves and transmission lines must give the student a basic approach to the phenomena involved, and concepts like Maximum Power Transfer and Mismatch must be understood. In the stationary frequency domain this concepts are usually clear, but the student may often feel a gap when trying to understand what happens in the time domain. The software presented will help the student in the understanding of the transient process of electromagnetic power in such situations. -
Article: Numerical evaluation of the Green's functions for arbitrarily shaped enclosures
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ABSTRACT: In this paper, a new spatial method has been implemented for the efficient calculation of the mixed potential Green's functions associated to electrical sources, when they are placed inside arbitrarily-shaped cylindrical cavities. The technique consists of placing electric dipole images and charges outside the cavity, imposing, at discrete points of the metallic wall, the appropriate boundary conditions for the potentials. Results show that the numerical convergence is attained fast. The cut-off frequencies and potential patterns for a trapezium-shaped waveguide are compared to those obtained by a standard finite elements technique, showing excellent agreement. Furthermore, a printed planar filter shielded in a square cavity has been analyzed with the new Green's functions, showing the practical value of the new theory. This work has been supported by Spanish National project CICYT-TEC2004-043 13-C02-02/TCM, and by Fundacion Séneca project, Ref. 02972/PI/05 -
Article: Numerical evaluation of the Green's functions for cylindrical enclosures by a new spatial images method
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ABSTRACT: A new and simple spatial images method has been implemented for the numerical calculation of the Green's functions in circular cylindrical enclosures. The technique is based on the imposition of the boundary conditions for the potentials, using a spatial images arrangement. Results show that the numerical convergence of the novel technique is attained fast. They also demonstrate that the new Green's functions lead to accurate results when analyzing real structures. The technique has been used for the efficient analysis of practical planar circuits shielded in circular cavities. -
Article: Enhanced topology for the design of bandpass elliptic filters employing inductive windows and dielectric objects
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ABSTRACT: This work presents a new topology for the design of bandpass elliptic filters employing inductive windows and dielectric objects. The proposed filtering structure combines, for the first time, the modified TE 102 resonating mode with the modified TE 201 mode. The TE 201 mode is excited by placing a wide dielectric post inside a waveguide cavity. The main advantage of the new topology is that two transmission zeros can be synthesized in the insertion loss response of the filter, for a second order structure. Also there is a high flexibility on the location of the transmission zeros. They can be synthesized along the frequency axis for maximum selectivity, or as a pair of complex poles for phase equalization. The authors thank Ministerio de Educación y Ciencia of Spain, which has supported this work under Grant TEC2007- 67630-C03-02/TCM. -
Article: Medidas sobre canales analógicos y digitales de televisión y su interpretación para la correcta planificación de sistemas de recepción
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ABSTRACT: El rápido avance de la radio y televisión digital está haciendo que los ingenieros y técnicos tengan que adaptar sus equipos de medidas, sus técnicas de instalación, y los conceptos tecnológicos adquiridos, para adecuarse a los nuevos requerimientos y parámetros de calidad de los servicios. En este contexto, el artículo aborda desde una perspectiva práctica diversos aspectos interesantes que hay que tener en cuenta a la hora de planificar la correcta instalación de sistemas de recepción digitales. La exposición se realiza desde la utilización de dos equipos muy útiles para el ingeniero y el técnico de telecomunicación, como son el analizador de espéctros y el medidor de campo, y cómo deben interpretarse las medidas obtenidas con estos equipos. -
Article: Proyecto ARIAM: desarrollo de un radiotelescópio y de un taller de Radioastronomía e Ingeniería de alta frecuencia como herramienta para el fomento de la cultura científica y tecnológica en la UPCT
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ABSTRACT: En esta comunicación pretendemos dar a conocer una iniciativa de fomento de la cultura científica y tecnológica dentro del área de Radioastronomía e Ingeniería de Telecomunicaciones, que se ha denominado proyecto ARIAM (Aula-taller de Radioastronomía e Ingeniería de Antenas y circuitos de Microondas). Esta iniciativa tiene como punto de inicio el desarrollo de un Radiotelescopio de microondas por parte de los alumnos de último cursos de la Escuela Técnica Superior de Ingeniería de Telecomunicación (ETSIT) de la Universidad Politécnica de Cartagena (UPCT). El Radiotelescopio consta, básicamente, de una antena parabólica de unos 3 metros de diámetro, de un receptor de microondas de elevada sensibilidad y ganancia, y de un sistema de adquisición de datos y control del apuntamiento de la antena. Se trata de un proyecto de ingeniería complejo y de un reto tecnológico, que involucra el desarrollo de varios subproyectos de naturaleza multidisciplinar. Están implicadas áreas temáticas como la ingeniería de antenas, la ingeniería de circuitos de microondas, la instrumentación electrónica, la ingeniería mecánica, técnicas de adquisición y procesado digital de la señal, la ingeniería de control y de motores, la astrofísica… etc. La novedad y el interés docente estriban en que todos estos subproyectos están siendo dirigidos por profesores de la UPCT, y son desarrollados íntegramente por alumnos de esta misma Universidad, utilizando los conocimientos y los laboratorios disponibles en las instalaciones de la UPCT. Es la primera vez en España que un sistema tan complejo y tecnológicamente avanzado como un Radiotelescopio está siendo desarrollado íntegramente con recursos humanos y tecnológicos de una Universidad Pública. Un objetivo fundamental de esta iniciativa es el de trasladar a la sociedad murciana en general, y a los más jóvenes en particular, un mensaje claro y vital en estos momentos: nuestros actuales y futuros estudiantes universitarios tienen a su disposición los medios para adquirir los conocimientos y habilidades necesarias que permiten abordar proyectos tan interesantes como los que se describirán en la ponencia. En esta misma ponencia se resumirá el trabajo realizado hasta la fecha durante los cuatro años que lleva en marcha esta actividad. Se mostrarán los resultados obtenidos, tanto a nivel técnico como a nivel humano, haciendo hincapié en la respuesta que han dado los alumnos a esta propuesta y las habilidades que ellos mismos están desarrollando gracias a este proyecto. Cabe destacar el trabajo en equipo, el carácter multidisciplinar del mismo, el desarrollo de habilidades prácticas y competencias profesionales como el manejo de maquinaria de fabricación de circuitos y estructuras, o de instrumentación de testeo y ajuste de circuitos… etc. El Radiotelescopio será usado para difundir entre alumnos, profesores y público en general la tecnología que hace posible la concepción y puesta en marcha del mismo, así como la disciplina de la Radioastronomía, tan interesante como desconocida. Con este objetivo de difusión, todos los sistemas que están siendo desarrollados tienen una finalidad claramente divulgativa, buscando siempre la claridad de los conceptos que se pretenden transmitir. Asimismo, en la ponencia se describirán las posibilidades de ampliación y mejora del Radiotelescopio, de manera que se entienda por qué este proyecto está pensado para ser más que un mero instrumento de observación, parte de un aula-taller de aprendizaje y difusión de la tecnología de antenas y circuitos de alta frecuencia. Por supuesto, este Radiotelescopio además de para divulgación será usado para tareas científicas de observación del Universo, y en concreto para detectar las señales de microondas originadas por el hidrógeno atómico presente en las nebulosas que pueblan nuestra Galaxia. Además de ser un instrumento para astrofísicos y radioastrónomos profesionales, el Radiotelescopio estará a disposición de las asociaciones astronómicas amateurs regionales, como la Agrupación Astronómica de la Región de Murcia (AARM) o la Asociación Astronómica de Cartagena (AAC). Además, el Radiotelescopio formará parte del proyecto internacional SETI (Search of Extraterrestrial Intelligence), cuya misión es buscar posibles señales de radio extraterrestres que tengan un origen artificial. En la ponencia se mostrarán las bondades de este proyecto ARIAM para fomentar el interés por las carreras de Ciencia e Ingeniería en nuestra Región. Además, este proyecto cuenta con el apoyo de varias universidades del territorio nacional y del Instituto Astrofísico de Canarias, adquiriendo un carácter interterritorial. El desarrollo del Radiotelescopio de ARIAM ha sido financiado por la Fundación regional Séneca durante los años 2006, 2007 y 2008. El desarrollo de este Radiotelescopio no habría sido posible sin la financiación ofrecida durante los años 2006, 2007 y 2008 por la Fundación Regional Séneca [37]. De igual o mayor valor es la ilusión mostrada por todos los alumnos de la ETSIT de la UPCT que han colaborado o están colaborando en el proyecto ARIAM, los cuales nombramos por orden cronológico: Ricardo Alarcón Llamas (LNAs v1.0, curso 2005-2006), Pedro Enrique Ros Avilés (mixer v1.0, curso 2005-2006), Anna Kamasheva (LNA v2.0, curso 2006-2007), Gonzalo Peñafiel Beltrán (LNA v3.0, curso 2006-2007), Mónica Moragón Serano (oscilador, curso 2006-2007), Adrián Juan Heredia (bocina, curso 2006-2007), Francisco J. Sandoval Piqueras (mixer v2.0, curso 2006-2007), Javier Molero Madrid (sistema, curso 2007-2008), Jesús Mora Rodríguez (sistema, curso 2007-2008) y Marta Rodríguez García Rodríguez (sistema, curso 2007-2008). Asimismo, la dedicación de los profesores Fernando Quesada Pereira, Alejandro Álvarez Melcón, Jose María Molina García-Pardo, David Cañete Rebenaque y José Luis Gómez Tornero, de la ETSIT de la UPCT, ha sido vital para conseguir llegar hasta el punto en el que está el proyecto ARIAM. -
Article: An efficient integral equation technique for the analysis of arbitrarily shaped capacitive waveguide circuits
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ABSTRACT: In this paper a new and efficient integral equation formulation is presented for the analysis of arbitrarily shaped capacitive waveguide devices. The technique benefits from the symmetry of the structure in order to reduce the dimensions of the problem from three to two dimensions. For the first time, this technique formulates the waveguide capacitive discontinuity problem as a 2D scattering problem with oblique incidence, com- bined with an efficient calculation of the parallel plate Green's functions. Results for a capacitive impedance transformer are successfully compared with measurements for validation of the proposed theory. Ministerio de Educación y Ciencia, Ref. TEC2007-67630-C03-02. Fundación Séneca, Ref. 08833/PI/08. -
Article: Analysis of inductive multiport microwave devices employing a novel double parallel plate approach
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ABSTRACT: The authors present a novel surface integral equation approach to analyse inductive microwave devices with several parallel input output ports containing inductive metallic and dielectric obstacles. The technique decomposes the main problem into three subproblems, employ- ing different kinds of Green's functions. One of the subproblems uses the classical Green's func- tions of an infinite unbounded medium with the constitutive parameters of the dielectric obstacles. A novel point of the technique is the formulation of the two other subproblems with two different, 908 rotated parallel plate regions. In these regions the parallel plate waveguide Green's functions are used to simplify the modelling of the excitation problem. The second novel aspect of the work is in the treatment of these Green's functions, to smooth their behaviour, and to improve their con- vergence. Several numerical results are presented to demonstrate the usefulness of the algorithms proposed. Also, several results for inductive microwave devices are presented to show the practical value of the approach. Ministerio de Educación y Ciencia, Ref. TEC2007-67630-C03-02. Fundación Séneca, Ref. 08833/PI/08 -
Article: Aplicación del Fast Multipole Method al análisis en 2D de objetos conductores inmersos en medios homogéneos multicapa empleando formulación de superficie
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ABSTRACT: In this paper, the Fast Multipole Method (FMM), one of the most important techniques developed in order to reduce the computational burden associated to the Method of Moments (MOM), is applied to analyze a 2D conducting bodies coated in a multilayered medium. A general formulation and some results are presented, which show the advantages of using the FMM in the solution of this kind of problems. An application of the usage of this formulation is included, showing how this method may be applied to the study of the effects of a dielectric shield (radome) in the radiation pattern of simple antennas. Este trabajo ha sido desarrollado con soporte del Proyecto Nacional Ref. TEC2004-04313-C02-02/TCM, y proyecto Regional Séneca Ref. PB/4/FS/02. -
Article: Cálculo eficiente de la función de Green en cavidades multicapa con sección transversal de tipo triángulo rectángulo-isósceles
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ABSTRACT: In this paper, an efficient calculation of the Green’s functions inside multilayered shielded cavities with right isosceles-triangular cross-section is presented. The method is entirely developed in the spatial domain and it is based on image theory. The idea is to use the Green’s functions inside a multilayered shielded square box in order to accurately obtain the Green’s functions of the triangular structure. It is shown that the new algorithm is very robust, with limited computational effort. Cut-off frequencies and potential patterns of a triangular cavity have been calculated and compared to those obtain by other techniques showing very good agreement. Finally, a transversal filter inside a multilayered triangular shaped cavity is designed, manufactured and tested using the developed technique. Este trabajo ha sido cofinanciado por el Ministerio de Educación y Ciencia (Proyecto: TEC2007-67630-C03-02, Beca: FPU-AP2006-015). -
Article: Dispersión de objetos 2D dieléctricos y magnéticos usando bases wavelet
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ABSTRACT: Lossy dielectric and magnetic obstacles are typically present in many high-frequency scattering applications. In this paper, we study this problem using the Equivalence Principle and the Method of Moments (MoM). When the structure is complex and high accuracy is required, the number of unknowns in the numerical solution naturally grows. Therefore, we propose the use of wavelet-like bases to improve the numerical efficiency and memory requirements. For verification purposes, the results provided by the new technique are successfully compared with those obtained with the conventional MoM approach. The new technique has been applied to characterize the scattering behavior of large square and elliptical obstacles, as well as multilayer structures, which are composed of lossy homogeneous media and conductors. Este trabajo ha sido financiado por el Ministerio de Educación y Ciencia, bajo los proyectos de investigación TEC2004/04313-C02-01, TEC2004/04313-C02-02, y el proyecto de la fundación Séneca PB/4/FS/02. -
Article: Analytical evaluation of the static MoM terms for volume and surface rectangular domains
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ABSTRACT: We present a simple analytical implementation of the static singular integrals arising in the volume/surface integral equation formulation for the analysis of mixed conducting and dielectric structures such as printed circuits with finite-size dielectric objects. The singularity of the Green's functions is extracted from the kernel of the integral equation as a static term. This term is then evaluated analytically for coincident rectangular cells in two and three dimensions. The new technique allows an accurate and efficient evaluation of method of moments (MoM) self-interactions compared to other methods previously used in the literature. Ministerio de Educación y Ciencia, Ref. TEC2007-67630-C03-02. Fundación Séneca, Ref. 08833/PI/08. -
Article: Broad band analysis of arbitrarily shaped microwave filters using a novel singular value decomposition technique
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ABSTRACT: A new full-wave electromagnetic analysis method based on the Boundary Integral Resonant Mode Expansion (BI-RME) is presented in this paper. The technique allows the computation of the broad band circuital response of arbitrarily shaped cavity filters. The coaxial excitation of this kind of filters is rigorously modeled by taking into account the high order modes on the coaxial aperture. A singular decomposition algebraic procedure has been implemented in order to obtain the solenoidal and non-solenoidal counterparts contributions of the electric current density inside the cavity needed by the BI-RME formulation. This method is simple and avoids some issues associated to star and loop based functions which are typically used for the same purpose. Ministerio de Educación y Ciencia, Ref. TEC2007-67630-C03-02. Fundación Séneca, Ref. 08833/PI/08. -
Article: Una técnica simple y efectiva para el análisis de antenas de hilo de grosor considerable
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ABSTRACT: This contribution presents a simple and efficient technique for the analysis of moderately thick wire antennas. The formulation uses the integral equation technique combined with the rigorous free space kernel expressed in terms of spherical Hankel function harmonics. The integral equation is solved using a full symmetric Galerkin algorithm combined with linear basis functions. The singular terms in the kernel are treated with a novel numerical procedure specially developed for wire antennas. The advantage of the technique is that it treats the rigorous kernel without complex analytical formulations, hence providing generality to treat complex wire geometries. Results show that the new technique developed is efficient and very accurate even for moderately thick wire antennas. -
Article: PAMELA: a useful tool for the study of leaky-wave modes in strip-loaded open dielectric waveguides
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ABSTRACT: A software tool is presented to help in the teaching of the electromagnetic theory of open dielectric waveguides. The study of the modal spectrum of canonical closed waveguides is a basic topic in any course of electromagnetics or microwave engineering. However, surface-wave modes and leaky-wave modes in open waveguides are not yet so well known in the academic environment. Nevertheless, this study is necessary, since novel open dielectric waveguides have been proposed for millimeter-wave and optical electronics in order to reduce the conductor losses. Therefore, the comprehension of the phenomenon of leaky-wave modes and behavior is indispensable for any future microwave engineer, who has to work with the new millimeter-wave and optical technologies. This program constitutes the first tool explicitly conceived to help the teaching of the working principles of open dielectric guides loaded with printed circuits, and the associated practical leaky-wave antennas (LWAs). The code can be a very good supplement to understand how practical leaky-wave antennas work, after a basic theoretical understanding of leaky waves has been first obtained. From the appearance of leaky-wave modes in open waveguides to the design of a backward-to-forward leaky-wave antenna, some simple and very clarifying step-by-step exercises are presented to illustrate these not-so-well-known concepts. Although the program refers to a specific type of open dielectric guides (laterally-shielded, top-open, stub-loaded, rectangular dielectric waveguides with planar perturbations), the results are applicable to any open dielectric guide, helping to teach the basic theory and topics relating to leaky- and surface-wave modes in uniform and periodic structures -
Article: Efficient analysis of inductive multiport waveguide circuits using a surface integral equation formulation
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ABSTRACT: This paper presents a simple and alternative approach for the analysis of inductive multiport waveguide microwave components. The technique uses a surface integral equation formulation to treat both metallic and dielectric objects inside the component structure. In order to avoid the relative convergence problem of other techniques based on mode matching, a novel port treatment is used. The technique is based on the application of the extinction theorem using the spatial representation of the Green's functions and image theory. Different complex H-plane structures are analyzed, including microwave bandpass filters with elliptic transfer functions and waveguide bends with dielectric posts. Results show the high accuracy and versatility of the new technique derived -
Article: Estudio de la propagación y radiación de pulsos temporales en líneas de transmisión basadas en metamateriales CRLH
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ABSTRACT: En este artículo se presenta un estudio sobre la propagación y la radiación de pulsos temporales en líneas de transmisión basadas en metamateriales CRLH. Esta nueva tecnología proporciona nuevas y originales soluciones en los recientes sistemas de banda ancha UWB. Usando una nueva formulación en el dominio temporal, se proponen dos novedosas aplicaciones. En primer lugar, el empleo de una antena CRLH leaky-wave como un analizador de espectros en tiempo real (RTSA) para caracterizar señales desconocidas, y en segundo, el uso de un array de antenas para obtener un barrido cuasi-instantáneo del espacio con un haz tipo “lápiz”. Este trabajo ha sido parcialmente financiado por el Ministerio de Educación y Ciencia (España). Los autores desean agradecer a Mr. Shulabh Gupta el apoyo, tanto técnico como personal, prestado en la realización de este trabajo. -
Article: Use of ground planes within the spatial images technique: Application to the analysis of rectangular multilayered shielded enclosures
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ABSTRACT: The use of ground planes is proposed inside the spatial images technique in order to calculate the multilayered shielded Green's functions for rectangular enclosures. The positions of the ground planes are dynamically located, covering two walls of the cavity, as a function of the source position. Spatial mirror images, related to the ground planes, are used to perfectly impose the boundary conditions along these cavity walls. This completely removes the problems associated to the singular behavior of the source when it is placed close to a wall or a corner, improving numerical stability. In addition, the method leads to a very efficient computation (about 15 times faster than the original approach), due to the reduced number of non-mirror images that must be effectively computed. A multi-band filter in hybrid waveguide-microstrip technology is analyzed with the new method, showing excellent agreement with measured data. Ministerio de Educación y Ciencia, Ref. TEC2007-67630-C03-02. Fundación Séneca, Ref. 08833/PI/08.
