Rius Casals, Juan-manuel
Total activity: 550
Areas of expertise
Antennas, Computational Electromagnetics, Electromagnetic scattering
Professional category
University professor
Doctoral courses
Doctor Ingeniero de Telecomunicación
University degree
Ingeniero de Telecomunicación
Research group
ANTENNALAB - Antennas and Wireless Systems Laboratory
Department
Department of Signal Theory and Communications
School
Barcelona School of Telecommunications Engineering (ETSETB)
E-mail
riustsc.upc.edu
Contact details
UPC directory Open in new window
Orcid
0000-0003-0606-5422 Open in new window
ResearcherID
F-7057-2013 Open in new window
Scopus Author ID
7006933058 Open in new window

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1 to 50 of 550 results
  • Volumetric testing with wedges for a nonconforming discretization of the Electric-Field Integral Equation

     Ubeda Farre, Eduardo; Rius Casals, Juan-manuel; Heldring, Alexander
    IEEE International Symposium on Antennas and Propagation
    p. 2192-2193
    DOI: 10.1109/APS.2014.6905423
    Presentation's date: 2014-07
    Presentation of work at congresses

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    The discretization in Method of Moments (MoM) of the Electric-Field Integral Equation (EFIE) is traditionally carried out with divergence-conforming sets of basis functions, like the RWG set. This enforces the normal continuity of the current across the edges arising from the discretization and makes the quasi-singular Kernel contributions numerically manageable. However, these MoM-implementations of the EFIE show little flexibility when handling nonconformal meshes, normally arising from from the juxtaposition or interconnection of independent meshes in the modular design of composite objects. A nonconforming discretization of the EFIE is possible if the testing procedure is carried out over volumetric elements attached to the surface triangulation, inside the body. In this paper, we present a new nonconforming discretization of the EFIE, where wedges attached to the source triangles are used as testing volumetric elements.

  • Nonconforming discretization of the Magnetic-Field Integral Equation with volumetric testing

     Ubeda Farre, Eduardo; Rius Casals, Juan-manuel; Heldring, Alexander
    IEEE International Symposium on Antennas and Propagation
    p. 2194-2195
    DOI: 10.1109/APS.2014.6905424
    Presentation's date: 2014-07
    Presentation of work at congresses

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    The RWG-discretization in Method of Moments (MoM) of the Magnetic-Field and Electric-Field Integral Equations (MFIE, EFIE) show evident discrepancy in the computed RCS, especially for small objects with edges and corners. The nonconforming monopolar-RWG discretization of the MFIE exhibits a smaller a deviation with respect to the EFIE. The Combined-Field Integral Equation (CFIE), which arises from the combination of the EFIE and the MFIE, is very often implemented with the RWG basis functions, whereby some accuracy with respect to EFIE is lost too. In this paper, we present a new nonconforming monopolar-RWG discretization of the MFIE, based on testing the magnetic field over small tetrahedral elements attached to the surface, inside the body under analysis. This formulation is compatible with a successful nonconforming discretization of the EFIE with the monopolar-RWG expansion of the current and volumetric testing. This allows the development of a nonconforming discretization of the CFIE.

  • RF monitoring of commercial vascular stents with dipole scattering resonances

     Arauz Garofalo, Gianluca; López Domínguez, Víctor; Hernández Ferras, Joan Manel; Rodríguez Leor, Oriol; Bayés Genis, Antoni; Rius Casals, Juan-manuel; O'callaghan Castella, Juan Manuel; García Santiago, Antoni; Tejada Palacios, Javier
    IEEE International Microwave Symposium
    p. 1-4
    DOI: 10.1109/MWSYM.2014.6848441
    Presentation's date: 2014-06-01
    Presentation of work at congresses

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    We have compared measurements and simulations of the microwave forward scattering of several commercial coronary stents. We immerse the stents in water to replicate the permittivity of biological tissues and find that their dipole scattering resonances can be detected at frequencies close to 300 MHz even though the stents are not purposely designed to facilitate such detection. We discuss how stent resonances can be used to monitor restenosis with non-invasive and non-ionizing techniques.

  • Grup de Teledetecció, Antenes, Microones i Superconductivitat

     Aguasca Sole, Alberto; Barlabe Dalmau, Antoni; Blanch Boris, Sebastian; Broquetas Ibars, Antoni; Camps Carmona, Adriano Jose; Cardama Aznar, Angel; Elias Fuste, Antonio; Duffo Ubeda, Nuria; Fabregas Canovas, Francisco Javier; Jofre Roca, Luis; Heldring, Alexander; López Martínez, Carlos; Mallorqui Franquet, Jordi Joan; O'callaghan Castella, Juan Manuel; Pradell Cara, Lluis; Rius Casals, Juan-manuel; Romeu Robert, Jordi; Torres Torres, Francisco; Ubeda Farre, Eduardo; Vall-llossera Ferran, Mercedes Magdalena; Duran Martinez, Israel; Wu, Lin; Gilasgar, Mitra; Lort Cuenca, Marc; Imbert Villa, Marc; Martin Alemany, Francisco; Chaparro Danon, David; Pablos Hernandez, Miriam; Pascual Biosca, Daniel; Park, Hyuk; Alonso Arroyo, Alberto; Onrubia Ibañez, Raul; Yam Ontiveros, Luis Eduardo; Rodriguez Silva, Juan Carlos; Piles Guillem, Maria; Deng, Xinping; Querol Borras, Jorge; Corbella Sanahuja, Ignasi
    Competitive project

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  • Sistemas Radiantes en milimétricas y submilimétricas para radar, comunicaciones e imágenes

     Rius Casals, Juan-manuel; Romeu Robert, Jordi; Blanch Boris, Sebastian; Elias Fuste, Antonio; Jofre Roca, Luis; Cardama Aznar, Angel
    Competitive project

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  • Iterative method of moments solution of problems involving electrically large and concave geometries

     Heldring, Alexander; Rius Casals, Juan-manuel; Ubeda Farre, Eduardo
    International Conference on Electromagnetics in Advanced Applications
    p. 266-269
    DOI: 10.1109/ICEAA.2013.6632235
    Presentation's date: 2013-09-09
    Presentation of work at congresses

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    This paper presents a study of the scaling with frequency (computational complexity) of preconditioned iterative solution, using the Multilevel Fast Multipole Method, of a class of radiation and scattering problems that exhibits particularly slow convergence: problems involving electrically large, open and concave geometries. A comparison is presented between a well-known state of the art preconditioner (ILU) and a recently introduced preconditioning method, the Multiscale Compressed Block Decomposition.

  • Volumetric testing for a nonconforming discretization in method of moments of the electric-field surface integral equation

     Ubeda Farre, Eduardo; Rius Casals, Juan-manuel; Heldring, Alexander
    International Conference on Electromagnetics in Advanced Applications
    p. 121-124
    DOI: 10.1109/ICEAA.2013.6632202
    Presentation's date: 2013-09
    Presentation of work at congresses

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    Implementations in Method of Moments of the Electric-Field Integral Equation (EFIE) are traditionally carried out with divergence-conforming sets, with normal continuity of the current across edges. This gives rise to awkward implementations around junctions in composite dielectric objects. Also, RWG-implementations of the Combined-Field Integral Equation for sharp-edged objects suffer from some loss of accuracy. In this paper, we present a new nonconforming discretization of the EFIE, with no continuity requirements across edges. In the generation of the impedance elements, we employ a volumetric testing over a set of tetrahedral elements attached to the meshed surface to let the hyper-singular Kernel contributions numerically manageable. We show that the decomposition of the current into normally-continuous and discontinuous contributions leads to enhanced accuracy in the computed RCS.

  • Discretization of the EFIE in Method of Moments without continuity of the normal current component across edges

     Ubeda Farre, Eduardo; Rius Casals, Juan-manuel; Heldring, Alexander
    IEEE International Symposium on Antennas and Propagation
    p. 448-449
    DOI: 10.1109/APS.2013.6710885
    Presentation's date: 2013-07-08
    Presentation of work at congresses

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    The discretization in Method of Moments (MoM) of the Electric-Field Integral Equation (EFIE) is traditionally carried out by preserving the continuity of the normal component in the expansion of the current across the edges arising from the discretization. This allows the cancellation of the hyper-singular Kernel contributions arising from the discretization of the EFIE. Divergence-conforming sets, like the RWG set, appear then as suitable choices to generate successful MoM-EFIE implementations. In this paper, we present a novel MoM- discretization of the EFIE with the non-conforming monopolar- RWG basis functions, with jump discontinuities in the expanded normal component of the current. We show with RCS results that the new EFIE implementation shows good agreement with the traditional normal-continuous RWG-implementation.

  • Preconditioning the Electric Field Integral Equation with the MS-CBD method

     Heldring, Alexander; Ubeda Farre, Eduardo; Rius Casals, Juan-manuel
    Iberian Meeting on Computational Electromagnetics
    Presentation's date: 2013-05-14
    Presentation of work at congresses

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    A novel preconditioning scheme for Method of Moment computations is proposed. It consists of an adapted version of an accelerated direct solution method, the Multiscale Compressed Block Decomposition. It is of particular interest for accelerating the convergence of the iterative solution of open problems that are electrically large and exhibit strong concavity. For such problems, when solved with the Multilevel Fast Multipole Algorithm, the convergence is the main efficiency bottleneck. The novel scheme is compared with the de facto standard preconditioner ILU for a representative problem and shown to be considerably more efficient

  • Fast shadowing computation in physical optics surface

     Rius Casals, Juan-manuel; Carbo, Alex; Ubeda Farre, Eduardo; Heldring, Alexander
    Iberian Meeting on Computational Electromagnetics
    Presentation's date: 2013-05-14
    Presentation of work at congresses

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    GRECO code has been updated by replacing the graphical processing technique for computation of Physical Optics surface integral by a hybrid CPU-graphical processing approach. The resulting code needs more CPU power for complex radar targets, but is free from the pixel discretization noise inherent to graphical processing. It has the same accuracy as conventional Physical Optics computation, but is an order of magnitude faster than the most efficient implementations with NlogN shadowed facets detection

    GRECO code has been updated by replacing the graphical processing technique for computation of Physical Optics surface integral by a hybrid CPU-graphical processing approach. The resulting code needs more CPU power for complex radar targets, but is free from the pixel discretization noise inherent to graphical processing. It has the same accuracy as conventional Physical Optics computation, but is an order of magnitude faster than the most efficient implementations with NlogN shadowed facets detection.

  • The multiscale compressed block decomposition as a preconditioner for method of moments computations

     Heldring, Alexander; Ubeda Farre, Eduardo; Rius Casals, Juan-manuel
    European Conference on Antennas and Propagation
    p. 390-393
    Presentation's date: 2013-04-08
    Presentation of work at congresses

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    A new preconditioner for Method of Moments computations is presented. It is based on a direct solver, the Multiscale Compressed Block Decomposition method, which has been adapted to reduce storage requirements and setup time. Numerical experiments show considerable improvement in overall efficiency in comparison with common preconditioners such as Incomplete LU decomposition, in particular for problems involving electrically large, open geometries.

    A new preconditioner for Method of Moments computations is presented. It is based on a direct solver, the Multiscale Compressed Block Decomposition method, which has been adapted to reduce storage requirements and setup time. Numerical experiments show considerable improvement in overall efficiency in comparison with common preconditioners such as Incomplete LU decomposition, in particular for problems involving electrically large, open geometries.

  • GRECO Code Rejuvenated: hybrid CPU-graphical processing

     Rius Casals, Juan-manuel; Carbo, Alex; Ubeda Farre, Eduardo; Heldring, Alexander
    European Conference on Antennas and Propagation
    p. 2348-2351
    Presentation's date: 2013-04-10
    Presentation of work at congresses

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    GRECO code has been updated by replacing the graphical processing technique for computation of Physical Optics surface integral by a hybrid CPU-graphical processing approach. The resulting code needs more CPU power for complex radar targets, but is free from the pixel discretization noise inherent to graphical processing. It has the same accuracy as conventional Physical Optics computation, but is an order of magnitude faster than the most efficient implementations with NlogN shadowed facets detection.

  • Stable discretization of the electric-magnetic field integral equation with the divergence Taylor-Orthogonal basis functions

     Ubeda Farre, Eduardo; Tamayo Palau, Jose Maria; Rius Casals, Juan-manuel
    IEEE International Symposium on Antennas and Propagation
    DOI: 10.1109/APS.2012.6348616
    Presentation's date: 2012-07-12
    Presentation of work at congresses

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  • Discretization of surface integral equations using conforming and non-conforming basis functions

     Ubeda Farre, Eduardo; Ylä-Oijala, Pasi; Tamayo Palau, Jose Maria; Kiminki, Sami P.; Rius Casals, Juan-manuel; Järvenpää, Seppo
    IEEE International Symposium on Antennas and Propagation
    Presentation's date: 2012-07-11
    Presentation of work at congresses

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  • Validation of a sea surface model for simulations of dynamic maritime SAR images

     Yam Ontiveros, Luis Eduardo; Mallorqui Franquet, Jordi Joan; Rius Casals, Juan-manuel
    IEEE International Geoscience and Remote Sensing Symposium
    p. 2813-2816
    DOI: 10.1109/IGARSS.2012.6350847
    Presentation's date: 2012-07-24
    Presentation of work at congresses

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    Controllable maritime scenarios have become a central issue in the research of new applications of SAR imaging to vessel monitoring systems. Numerical tools such as GRECOSAR, a SAR simulator of complex targets, are able to provide suitable test-beds as long as the model of the targets (vessels) and the sea surface resemble to what is expected in real maritime scenes. This paper presents the validation of SAR simulated images from GRECOSAR while using a dynamic and multi-harmonic elevation model of the sea surface. The simulations are carried out for generic C- and X-band SAR sensors. The results of the co-polar cha nnels are compared with K,lognormal, Weibull and Rayleigh distributions, which are commonly used to describe statistics of real SAR images of the sea surface. The results show that the clutter has statistics clos er to the K and Weibull distributions, suggesting that the elevation model presented can provide a more realistic approach in simulating SAR images of maritime scenarios

  • Discretization of the electric-magnetic field integral equation with the divergence Taylor-Orthogonal basis functions free from the magnetic-field and the electric-field low-frequency breakdowns

     Ubeda Farre, Eduardo; Tamayo Palau, Jose Maria; Rius Casals, Juan-manuel
    European Conference on Antennas and Propagation
    p. 707-711
    DOI: 10.1109/EuCAP.2012.6206631
    Presentation's date: 2012
    Presentation of work at congresses

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  • Sparsified ACA for accelerated iterative solution of the MoM linear system

     Heldring, Alexander; Rius Casals, Juan-manuel; Ubeda Farre, Eduardo; Tamayo Palau, Jose Maria
    Iberian Meeting on Computational Electromagnetics
    p. 13-15
    Presentation's date: 2011-11-02
    Presentation of work at congresses

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    A new algorithm, the Sparsified Adaptive Cross Approximation (SPACA) is presented for fast iterative solution of the Method of Moments linear system. Like ordinary ACA, it is a completely kernel-independent method, but it is faster and yields a higher compression rate than ordinary ACA, without compromising the accuracy. As an example, the RCS of a perfectly conducting sphere is computed using up to 786,432 basis functions. It is shown that SPACA exhibits close to NlogN complexity for this problem.

    Postprint (author’s final draft)

  • Block LU decomposition versus partitioned matrix inverse for compressed direct solution of method of moments linear system

     Heldring, Alexander; Rius Casals, Juan-manuel
    Iberian Meeting on Computational Electromagnetics
    p. 9-12
    Presentation's date: 2011-11-02
    Presentation of work at congresses

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  • Design and synthesis of a new class of receiver filters

     Mateu Mateu, Jordi; Collado Gomez, Juan Carlos; Padilla Díaz, Alberto; Rius Casals, Juan-manuel; O'callaghan Castella, Juan Manuel; Cuñado, O; Torra, J; Mingot, S; Ernst, Cristoph
    ESA Techno/Innovation Days
    p. 22-23
    Presentation's date: 2011-11-23
    Presentation of work at congresses

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  • Accelerated direct solution of the MoM linear system using block compression and nested factorization

     Heldring, Alexander; Rius Casals, Juan-manuel
    International Conference on Electromagnetics in Advanced Applications
    p. 636-639
    DOI: 10.1109/ICEAA.2011.6046415
    Presentation's date: 2011-09-13
    Presentation of work at congresses

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    A comparison is presented between different algorithms for direct (non-iterative) accelerated solution of the Method of Moments. The alternatives are common block LU factorization and Compressed Block Decomposition (CBD), and their respective nested, or Multi Scale (MS) implementations. The comparison includes theoretical considerations and numerical examples.

  • Divergence-Taylor-Orthogonal basis functions for the discretization of second-kind surface integral equations in the Method of Moments

     Ubeda Farre, Eduardo; Tamayo Palau, Jose Maria; Rius Casals, Juan-manuel
    Computational Electromagnetics International Workshop
    p. 8-12
    DOI: 10.1109/CEM.2011.6047318
    Presentation's date: 2011-08-11
    Presentation of work at congresses

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  • Facet-Oriented Discretization of the Electric-Magnetic Field Integral Equation for the accurate scattering analysis of perfectly conducting sharp-edged objects

     Tamayo Palau, Jose Maria; Ubeda Farre, Eduardo; Rius Casals, Juan-manuel
    IEEE International Symposium on Antennas and Propagation
    p. 194-196
    DOI: 10.1109/APS.2011.5996675
    Presentation's date: 2011-07-04
    Presentation of work at congresses

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  • Research & Development of a Simulator for Moving Target Indicator System

     Makhoul Varona, Eduardo; Rius Casals, Juan-manuel; Aguasca Sole, Alberto; O'callaghan Castella, Juan Manuel; Mallorqui Franquet, Jordi Joan; Broquetas Ibars, Antoni
    Competitive project

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  • Discretization of the Electric-Magnetic field integral equation with the Divergence-Taylor-Orthogonal basis functions

     Ubeda Farre, Eduardo; Tamayo Palau, Jose Maria; Rius Casals, Juan-manuel
    European Conference on Antennas and Propagation
    p. 2613-2617
    Presentation's date: 2011-04-11
    Presentation of work at congresses

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  • Multilevel adaptive cross approximation and direct evaluation method for fast and accurate discretization of electromagnetic inegral equations  Open access

     Tamayo Palau, José María
    Department of Signal Theory and Communications, Universitat Politècnica de Catalunya
    Theses

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    El objetivo de esta tesis es dotarse de una metodología de análisis dinámica en el tiempo que permite revalorar permanentemente la problemática de la escasez de agua dulce en función de la oferta y la demanda. Para ello, hemos tenido en cuenta las variaciones de sus factores conductores, y entre ellos sobre todo el de las necesidades en el desarrollo humano. La metodología es de manejo operativo, en la que se puedan introducir de manera rápida y sencilla los cambios en las variables que van a determinar la oferta y la demanda dinámica de agua dulce.La propuesta metodológica se caracteriza por varios puntos clave. En primer lugar, desarrollamos una discusión terminológica y conceptual en la que, a partir del estado del arte actual llegamos a definir los conceptos de la oferta y la demanda dinámica de agua dulce renovable como primer paso fundamental de nuestra metodología, elaborando un glosario terminológico y conceptual propio para este trabajo.A partir de la caracterización de la oferta y la demanda dinámica se analiza el escenario business as usual constatándose y valorándose la gravedad de la situación de los nueve países que forman la región del golfo de Guinea, debida fundamentalmente a la no existencia o a la no implementación de gestión de extracción, distribución y abastecimiento de agua dulce por falta de recursos económicos o voluntades políticas. Nuestro segundo paso metodológico permite corroborar la calificación usual de la situación de estos países como de escasez económica. Para poder cubrir esta etapa de la propuesta metodológica ha sido necesario resolver, también metodológicamente, la muy importante escasez de datos para la mayoría de países en desarrollo.Nuestra propuesta metodológica parte por supuesto de trabajar con la realidad, detectando inconvenientes y limitaciones al aplicarla al caso de estudio de los países de nuestra región. Una de estas limitaciones es claramente la falta de datos necesarios para elaborar nuestros escenarios o para determinar los estándares o confeccionar el nuevo índice; en la medida que se han ido presentando estas circunstancias, hemos recurrido a soluciones metodológicas que nos han permitido estimar nuevos datos a partir de correlaciones y/o extrapolaciones de los datos existentes.El siguiente punto clave y una de las aportaciones principales de este trabajo de propuesta metodológica es a partir de unas determinadas objetivizaciones de estándares de demanda de agua dulce ligados a unos niveles aceptables de bienestar y calidad de vida, reanalizar mediante la construcción y análisis de los escenarios de futuro correspondientes, las posibilidades y debilidades reales de estos países en relación con la escasez de agua dulce.El último punto clave es la elaboración de una propuesta de un índice que nos permite evaluar de forma sintética y rápida la situación de un país o región según el nivel de capacidad para satisfacer demandas de agua dulce correspondientes a un estándar de demanda establecido de forma clara y explícita. Dicho índice nos permite detectar de forma temprana posibles alertas que más allá de una escasez física o económica nos sean útiles (al igual que en el caso de la representación y el análisis de los resultados de los distintos escenarios de futuro) para la toma decisiones, en función de los objetivos pretendidos.La herramienta de apoyo para elaborar las representaciones de los escenarios es, en sí misma, otro elemento instrumental que además de tener una buena resolución de diseño gráfico, debe facilitar los cálculos necesarios para el análisis de los escenarios, así como almacenar la información de forma cómoda y en la que se puedan introducir cambios fácilmente.La metodología es una herramienta objetiva y útil dirigida a responsables políticos y técnicos, estudiosos e investigadores que dé soporte a la toma de decisiones y/o a la visualización de la valoración de la escasez de agua dulce en el marco de un pretendido desarrollo humano sostenible.

    This thesis describes a methodology for dynamic analysis over time that makes it possible to continually re-assess fresh-water scarcity as a function of supply and demand. The methodology takes into account variations in the driving factors, including, most importantly, human-development needs. The methodology can be controlled operationally. Changes in the variables that determine the dynamic fresh-water supply and demand can be entered quickly and easily.Our methodological proposal contains several key points. We begin with a discussion of terminology and concepts. Taking the current state of the art as our starting point, as a fundamental first step in our methodology we define the concepts of dynamic renewable fresh-water supply and demand. We then present a glossary of the terms and concepts used in this thesis.Following the characterisation of dynamic supply and demand, we analyse the "business-as-usual" scenario. We point out the seriousness of the situation in the nine Gulf of Guinea countries. The fundamental reason for this situation is the non-existence or non-implementation of policies aimed at extracting, distributing and supplying fresh water, due to a lack of economic resources or political will. The second step in our methodology is to corroborate the usual description of the situation in these countries, particularly in terms of the economic scarcity that characterises them. To properly complete this stage of the methodology, it has been necessary to find a solution to the inadequacy of the data available in most developing countries.Our proposal works with reality, which involves detecting disadvantages and limitations when applying the methodology in the countries of this particular region. One such limitation, clearly, is the lack of the necessary data for constructing the scenarios, determining the standards and creating the new index; as these circumstances have arisen, we have implemented methodological solutions that have enabled us to estimate new data on the basis of correlations and/or extrapolations of existing data.The next key point is also one of the main contributions of this methodological proposal. We set the goal of achieving certain standards of fresh-water demand based on acceptable levels of welfare and quality of life. Then, by constructing and analysing the corresponding future scenarios, we re-examine the real possibilities and weaknesses of each country as relates to the scarcity of fresh water.The last key point of our proposal is the generation of an index that enables us to evaluate, quickly and synthetically, the situation of a particular country or region on the basis of its capacity to satisfy fresh-water demand in a way that meets a clearly and specifically defined standard. This index enables the early detection of possible problems that go beyond physical or economic scarcity. Like the representation and analysis of the results of the various future scenarios, this early-warning system will enable decisions to be made in accordance with the established goals.The support tool used to generate the representations of the scenarios must have good graphic-design resolution, be able to make the calculations necessary for analysing the scenarios, and store the information in a practical way that allows changes to be entered easily.This methodology is meant to be used by politicians, engineers, scholars and researchers as a useful and objective support tool for decision-making and/or visualising levels of fresh-water scarcity as part of larger efforts to achieve the goal of sustainable human development.

  • Multilevel adaptive cross approximation and direct evaluation method for fast and accurate discretization of electromagnetic integral equations  Open access  awarded activity

     Tamayo Palau, José María
    Department of Signal Theory and Communications, Universitat Politècnica de Catalunya
    Theses

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    El objetivo de esta tesis es dotarse de una metodología de análisis dinámica en el tiempo que permite revalorar permanentemente la problemática de la escasez de agua dulce en función de la oferta y la demanda. Para ello, hemos tenido en cuenta las variaciones de sus factores conductores, y entre ellos sobre todo el de las necesidades en el desarrollo humano. La metodología es de manejo operativo, en la que se puedan introducir de manera rápida y sencilla los cambios en las variables que van a determinar la oferta y la demanda dinámica de agua dulce.La propuesta metodológica se caracteriza por varios puntos clave. En primer lugar, desarrollamos una discusión terminológica y conceptual en la que, a partir del estado del arte actual llegamos a definir los conceptos de la oferta y la demanda dinámica de agua dulce renovable como primer paso fundamental de nuestra metodología, elaborando un glosario terminológico y conceptual propio para este trabajo.A partir de la caracterización de la oferta y la demanda dinámica se analiza el escenario business as usual constatándose y valorándose la gravedad de la situación de los nueve países que forman la región del golfo de Guinea, debida fundamentalmente a la no existencia o a la no implementación de gestión de extracción, distribución y abastecimiento de agua dulce por falta de recursos económicos o voluntades políticas. Nuestro segundo paso metodológico permite corroborar la calificación usual de la situación de estos países como de escasez económica. Para poder cubrir esta etapa de la propuesta metodológica ha sido necesario resolver, también metodológicamente, la muy importante escasez de datos para la mayoría de países en desarrollo.Nuestra propuesta metodológica parte por supuesto de trabajar con la realidad, detectando inconvenientes y limitaciones al aplicarla al caso de estudio de los países de nuestra región. Una de estas limitaciones es claramente la falta de datos necesarios para elaborar nuestros escenarios o para determinar los estándares o confeccionar el nuevo índice; en la medida que se han ido presentando estas circunstancias, hemos recurrido a soluciones metodológicas que nos han permitido estimar nuevos datos a partir de correlaciones y/o extrapolaciones de los datos existentes.El siguiente punto clave y una de las aportaciones principales de este trabajo de propuesta metodológica es a partir de unas determinadas objetivizaciones de estándares de demanda de agua dulce ligados a unos niveles aceptables de bienestar y calidad de vida, reanalizar mediante la construcción y análisis de los escenarios de futuro correspondientes, las posibilidades y debilidades reales de estos países en relación con la escasez de agua dulce.El último punto clave es la elaboración de una propuesta de un índice que nos permite evaluar de forma sintética y rápida la situación de un país o región según el nivel de capacidad para satisfacer demandas de agua dulce correspondientes a un estándar de demanda establecido de forma clara y explícita. Dicho índice nos permite detectar de forma temprana posibles alertas que más allá de una escasez física o económica nos sean útiles (al igual que en el caso de la representación y el análisis de los resultados de los distintos escenarios de futuro) para la toma decisiones, en función de los objetivos pretendidos.La herramienta de apoyo para elaborar las representaciones de los escenarios es, en sí misma, otro elemento instrumental que además de tener una buena resolución de diseño gráfico, debe facilitar los cálculos necesarios para el análisis de los escenarios, así como almacenar la información de forma cómoda y en la que se puedan introducir cambios fácilmente.La metodología es una herramienta objetiva y útil dirigida a responsables políticos y técnicos, estudiosos e investigadores que dé soporte a la toma de decisiones y/o a la visualización de la valoración de la escasez de agua dulce en el marco de un pretendido desarrollo humano sostenible.

    This thesis describes a methodology for dynamic analysis over time that makes it possible to continually re-assess fresh-water scarcity as a function of supply and demand. The methodology takes into account variations in the driving factors, including, most importantly, human-development needs. The methodology can be controlled operationally. Changes in the variables that determine the dynamic fresh-water supply and demand can be entered quickly and easily.Our methodological proposal contains several key points. We begin with a discussion of terminology and concepts. Taking the current state of the art as our starting point, as a fundamental first step in our methodology we define the concepts of dynamic renewable fresh-water supply and demand. We then present a glossary of the terms and concepts used in this thesis.Following the characterisation of dynamic supply and demand, we analyse the "business-as-usual" scenario. We point out the seriousness of the situation in the nine Gulf of Guinea countries. The fundamental reason for this situation is the non-existence or non-implementation of policies aimed at extracting, distributing and supplying fresh water, due to a lack of economic resources or political will. The second step in our methodology is to corroborate the usual description of the situation in these countries, particularly in terms of the economic scarcity that characterises them. To properly complete this stage of the methodology, it has been necessary to find a solution to the inadequacy of the data available in most developing countries.Our proposal works with reality, which involves detecting disadvantages and limitations when applying the methodology in the countries of this particular region. One such limitation, clearly, is the lack of the necessary data for constructing the scenarios, determining the standards and creating the new index; as these circumstances have arisen, we have implemented methodological solutions that have enabled us to estimate new data on the basis of correlations and/or extrapolations of existing data.The next key point is also one of the main contributions of this methodological proposal. We set the goal of achieving certain standards of fresh-water demand based on acceptable levels of welfare and quality of life. Then, by constructing and analysing the corresponding future scenarios, we re-examine the real possibilities and weaknesses of each country as relates to the scarcity of fresh water.The last key point of our proposal is the generation of an index that enables us to evaluate, quickly and synthetically, the situation of a particular country or region on the basis of its capacity to satisfy fresh-water demand in a way that meets a clearly and specifically defined standard. This index enables the early detection of possible problems that go beyond physical or economic scarcity. Like the representation and analysis of the results of the various future scenarios, this early-warning system will enable decisions to be made in accordance with the established goals.The support tool used to generate the representations of the scenarios must have good graphic-design resolution, be able to make the calculations necessary for analysing the scenarios, and store the information in a practical way that allows changes to be entered easily.This methodology is meant to be used by politicians, engineers, scholars and researchers as a useful and objective support tool for decision-making and/or visualising levels of fresh-water scarcity as part of larger efforts to achieve the goal of sustainable human development.

  • Design, simulation and measurement of millimetre wave antennas for comunications and imaging

     Blanch Boris, Sebastian; Cardama Aznar, Angel; Jofre Roca, Luis; Romeu Robert, Jordi; Roqueta Crusats, Gemma; Guardiola Garcia, Marta; Serrano Calvo, Raquel; Izquierdo Fernandez, Benjamin; Alonso Valdesueiro, Javier; Capdevila Cascante, Santiago; Monsalve Carcelen, Beatriz; Diaz Tapia, Edgar; Rodrigo Lopez, Daniel; Nova Lavado, Enrique; Tamayo Palau, Jose Maria; Rius Casals, Juan-manuel
    Competitive project

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  • Simulation of shipborne small HF antennas with RWG discretization and fast solver

     Rius Casals, Juan-manuel; Jofre Roca, Luis; Tamayo Palau, Jose Maria; Heldring, Alexander; Ubeda Farre, Eduardo
    IEEE International Conference on Wireless Information Technology and Systems
    DOI: 10.1109/ICWITS.2010.5611892
    Presentation's date: 2010-09-01
    Presentation of work at congresses

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    In this paper, an alternative approach has been used to analyze an electrically small antenna (1.2m in the 2-30 MHz band) in a large ship (238m length) using a generic EFIE simulation code with Rao, Wilton and Glisson (RWG) basis functions, with the minimum necessary modifications to tackle the lowfrequency and multiscale issues that lead to a very poorly conditioned linear system.

  • New European Watcher

     Rius Casals, Juan-manuel; O'callaghan Castella, Juan Manuel; Makhoul Varona, Eduardo; Broquetas Ibars, Antoni
    Competitive project

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  • Software framework for integration of method of moments kernels with the Adaptive Cross Approximation (ACA) algorithm

     Espinosa, Hugo; Brick, Y.; Boag, Amir; Rius Casals, Juan-manuel
    Convention of Electrical and Electronics Engineers in Israel
    p. 634-636
    DOI: 10.1109/EEEI.2010.5662139
    Presentation's date: 2010-08-18
    Presentation of work at congresses

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    Fast direct solution of the combined field integral equation  Open access

     Heldring, Alexander; Tamayo Palau, Jose Maria; Rius Casals, Juan-manuel
    URSI Commission B International Symposium on Electromagnetic Theory
    Presentation's date: 2010-08-17
    Presentation of work at congresses

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    The Method of Moments for electromagnetic scattering and radiation problems is often used in conjunction with the EFIE because the EFIE allows the analysis of open surfaces. For electrically large closed surfaces, the CFIE is often much more efficient because it yields a well conditioned impedance matrix. This is particularly important when an iterative solution method is used. This paper compares the EFIE and the CFIE for a novel fast direct (non-iterative) solution method, the Multiscale Compressed Block Decomposition method.

  • New electric-magnetic field integral equation for the scattering analysis of perfectly conducting sharp-edged objects at very low or extremely low frequencies

     Ubeda Farre, Eduardo; Rius Casals, Juan-manuel
    IEEE International Symposium on Antennas and Propagation
    DOI: 10.1109/APS.2010.5561038
    Presentation's date: 2010-07-14
    Presentation of work at congresses

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    On the efficient evaluation of hyper-singular integrals in Galerkin surface integral equation formulations via the direct evaluation method  Open access

     Tamayo Palau, Jose Maria; Polimeridis, Athanasios G.; Rius Casals, Juan-manuel; Mosig, Juan Ramón
    IEEE International Symposium on Antennas and Propagation
    p. 1-4
    DOI: 10.1109/APS.2010.5561848
    Presentation's date: 2010-07-12
    Presentation of work at congresses

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    In this paper, the direct evaluation method tailored for the hyper-singular integrals arising in Galerkin surface integral equation formulations is developed.[...] The proposed method utilizes a series of coordinate transformations together with a re-ordering of the integrations in order to reduce the 4-D hyper-singular integrals to 2-D smooth integrals that can be easily computed via generalized Cartesian product rules based on standard Gauss quadratures, readily available in the literature. The direct evaluation method was originally introduced by Gray et al. for the evaluation of super hyper-singular Galerkin surface integrals arising in static problems and recently it was extended for the case of the weakly singular integrals in Galerkin MoM problems over coincident triangle elements.

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    Comparison of lossy filters and predistorted filters using novel software  Open access

     Padilla Díaz, Alberto; Mateu Mateu, Jordi; Collado Gomez, Juan Carlos; Ernst, Cristoph; Rius Casals, Juan-manuel; Tamayo Palau, Jose Maria; O'callaghan Castella, Juan Manuel
    IEEE International Microwave Symposium
    p. 1720-1723
    Presentation's date: 2010-05
    Presentation of work at congresses

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    Very accurate computation of the impedance elements on the discretization of the magnetic field integral equation with the orthogonal basis functions  Open access

     Tamayo Palau, Jose Maria; Ubeda Farre, Eduardo; Polimeridis, Athanasios G.; Rius Casals, Juan-manuel; Mosig, Juan Ramón
    Iberian Meeting on Computational Electromagnetics
    p. 48-52
    Presentation's date: 2010-05-19
    Presentation of work at congresses

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    We show a novel integrating technique, the direct evaluation method, that provides maximum accuracy in the computation of the MFIE-interactions between neighboring noncoplanar basis functions sharing an edge or a vertex of the discretization. Unlike the previous techniques, this strategy requires no extraction of quasi-singular terms from the Kernel and accounts for both inner- and outer-integrals. We show that the recently proposed discretization of the MFIE with orthogonal facet-oriented basis functions provide best accuracy in the RCS computation of objects with small electrical dimensions when compared with other conventional basis functions sets.

  • Application of lossy filter synthesis to a C-band cavity filter and its prospect for use in IMUX

     O'callaghan Castella, Juan Manuel; Padilla Díaz, Alberto; Mateu Mateu, Jordi; Rius Casals, Juan-manuel; Tamayo Palau, Jose Maria; Collado Gomez, Juan Carlos; Rocas Cantenys, Eduard
    Microwave Technology and Techniques Workshop
    Presentation's date: 2010-05-12
    Presentation of work at congresses

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  • Lossy filter synthesis of L-band planar filters using novel software

     Padilla Díaz, Alberto; Mateu Mateu, Jordi; Collado Gomez, Juan Carlos; Ernst, Cristoph; Rius Casals, Juan-manuel; Tamayo Palau, Jose Maria; O'callaghan Castella, Juan Manuel; Rocas Cantenys, Eduard
    Microwave Technology and Techniques Workshop
    p. 1
    Presentation's date: 2010-05-12
    Presentation of work at congresses

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    Lossy synthesis techniques are used to synthesize high performance filters using resonators with a finite Q. With these techniques a transmission response of a lossless filter with lowest possible roll-off is obtained, except for an overall constant additional insertion loss. The out-of band performance is not affected. These types of filters are useful in receiver architectures where the filter can be placed following an amplifying stage and some increase in insertion loss can be tolerated without affecting the noise figure. Due to the lower resonator Q that can be employed, low cost and compact filters (such as microstrip filters) can be realized. Hence this work presents the synthesis and design of two planar lossy filters. Both filters have been designed using microstrip technology, with center frequencies of 1 GHz and 1.6 GHz, and bandwidth of 36 MHz and 80 MHz, respectively. Both filters exhibit a flat in-band response with an insertion loss of 10 dB and 7.5 dB, respectively. The topologies obtained from the synthesis result in a 4th and a 6th order filters at 1 GHz and 1.6 GHz, respectively. Both topologies present a uniform Q distribution throughout the networks, this is all the resonators of the filter are equal to 200 and 290, respectively. In contrast with conventional filter networks, where all the couplings are reactive, lossy filters require some of the couplings to be resistive. The main difference between the two filters presented is the type of frequency response. While the filter at 1 GHz synthesizes a response with a stopband 10 dB return loss, the filter at 1.6 GHz synthesizes a purely reflective response in the stopband. The presentation will also show details of the software package that has been written to synthesize filters following various forms of pre-distortion, classical (no-loss considered in the synthesis) and lossy filter synthesis. This software obtains the coupling matrix of several network topologies for a given response and allows performing rotations on them to find the desired topology. Additionally, the software allows to evaluate the effect of loss in the networks resulting from the synthesis, even in those cases where the synthesis results in an ideal lossless network (i.e., classical and pre-distortion synthesis).

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    Accelerated direct solution of the MoM-VIE for dielectric scatterers  Open access

     Heldring, Alexander; Tamayo Palau, Jose Maria; Rius Casals, Juan-manuel; Ubeda Farre, Eduardo
    Iberian Meeting on Computational Electromagnetics
    p. 25-29
    Presentation's date: 2010-05-19
    Presentation of work at congresses

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    The Multiscale Compressed Block Decomposition algorithm (MS-CBD), a direct (non-iterative) linear solver, is applied to accelerate the solution of the MoM-VIE formulation for dielectric scatterers. Numerical solutions are presented for problems with several hundreds of thousands of unknowns. Asymptotically (with respect to the electrical size of the problem), the solution time scales with the number of unknowns squared. The numerical examples confirm this theoretical value.

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    New results from the SoftLAB benchmark of antenna software  Open access

     Rolland, Anthony; Gillard, Raphael; Sauleau, Ronan; Eberhard, Jens; Rius Casals, Juan-manuel; Cappellin, Cecilia; Vandenbosch, Guy
    European Conference on Antennas and Propagation
    Presentation's date: 2010-04-14
    Presentation of work at congresses

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    This paper gives an overview of the antenna software benchmarking activity that took place within the Software Group of the EurAAP association in 2009. A particular focus is brought to one of the proposed test case that consists of a non conventional horn antenna

  • Orthogonal basis functions for the discretization of the Magnetic-field Integral Equation in the low frequency regime

     Ubeda Farre, Eduardo; Tamayo Palau, Jose Maria; Rius Casals, Juan-manuel
    European Conference on Antennas and Propagation
    p. 1-4
    Presentation's date: 2010-04-15
    Presentation of work at congresses

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  • Software framework for integration of method of moments kernels with direct or iterative fast solvers

     Rius Casals, Juan-manuel; Herrero, J. A.; Tamayo Palau, Jose Maria; Heldring, Alexander; Ubeda Farre, Eduardo; Parrón, Josep; López-Peña, Sergio; Polimeridis, Athanasios G.; Mosig, Juan Ramón; Espinosa, Hugo; Boag, Amir
    European Conference on Antennas and Propagation
    p. 1-2
    Presentation's date: 2010-04-15
    Presentation of work at congresses

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  • Direct MoM solution of electrically large problems with N2 complexity

     Heldring, Alexander; Rius Casals, Juan-manuel; Tamayo Palau, Jose Maria
    European Conference on Antennas and Propagation
    Presentation's date: 2010-04-15
    Presentation of work at congresses

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  • Analysis of numerical integration in the evaluation of hyper-singular integrals in Galerkin surface integral equation formulations via the direct evaluation method

     Tamayo Palau, Jose Maria; Polimeridis, Athanasios G.; Rius Casals, Juan-manuel; Heldring, Alexander; Mosig, Juan Ramón
    European Conference on Antennas and Propagation
    p. 1-5
    Presentation's date: 2010-04-16
    Presentation of work at congresses

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    GILABVIR: Virtual laboratories and remote laboratories in engineering. A teaching innovation group of interest  Open access

     Cabrera Bean, Margarita Asuncion; Bragos Bardia, Ramon; Pérez, Marimar; Mariño Acebal, Jose Bernardo; Rius Casals, Juan-manuel; Gomis Bellmunt, Oriol; Casañ Guerrero, Maria Jose; Gironella i Cobos, Framcesc Xavier
    IEEE Annual Engineering Education Conference
    p. 1-6
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    GILABVIR (Grup d’Interès en Laboratoris Virtuals i Remots) is a recently created Virtual and Remote Laboratory Group of Interest of UPC (Universitat Politècnica de Catalunya) and it is integrated in a more general teaching innovation project. RIMA [1], [2]. RIMA has been developed to promote research on the use of innovative learning methodologies applied to engineering education and it was specially created to assess in the new European higher education adaptation process.

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    A remote laboratory to promote the interaction between university and secondary education  Open access

     Cabrera Bean, Margarita Asuncion; Bragos Bardia, Ramon; Pérez, Marimar; Sánchez Terrones, Benjamin; Guasch Petit, Antonio; Garófano, F.; Gomis Bellmunt, Oriol; Rius Casals, Juan-manuel; Casañ Guerrero, Maria Jose
    IEEE Annual Engineering Education Conference
    p. 1-5
    DOI: 10.1109/EDUCON.2010.5492559
    Presentation of work at congresses

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    iLabRS is a remote laboratory developed in Telecom BCN, the Telecom and Electronics Engineering School of the UPC with the key participation of a Secondary Education Technology teacher. Students and teachers can access to real experiments in the electronics and physics areas using a web browser. The remote experiments have been designed to partially cover the technology curriculum in the last two high school years with a triple goal: (1) to enrich the set of laboratory experiences available in High Schools, (2) to provide a clear example of the possibilities of internet-based technologies and (3) to promote the interaction between University and Secondary Education. Currently, there are 13 different experiments available. A pilot evaluation experience was carried out, in collaboration with 7 High Schools and around 100 students participating. In the experience assessment, the students gave a mark of 3.8/5 and the teachers of 4.4/5.

  • Framework for integration of fast solvers in method of moments kernels

     Rius Casals, Juan-manuel; Tamayo Palau, Jose Maria; Heldring, Alexander; Parrón, Josep; Ubeda Farre, Eduardo
    LEMA-EPFL Workshop on Integral Techniques for Electromagnetics
    Presentation's date: 2009-09-08
    Presentation of work at congresses

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    Application of Multilevel Adaptive Cross Approximation (MLACA) to electromagnetic scattering and radiation problems  Open access

     Tamayo Palau, Jose Maria; Heldring, Alexander; Rius Casals, Juan-manuel
    International Conference on Electromagnetics in Advanced Applications
    p. 1-4
    Presentation's date: 2009-09-14
    Presentation of work at congresses

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    Zeroth-order divergence-complete discretizations of the EFIE at very low frequencies  Open access

     Ubeda Farre, Eduardo; Tamayo Palau, Jose Maria; Rius Casals, Juan-manuel
    Computational Electromagnetics Workshop
    p. 1-4
    Presentation's date: 2009-07-20
    Presentation of work at congresses

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    We present the Self-Loop basis functions, an edge-oriented divergence-conforming set with zero charge density. These basis functions allow a rearrangement of the Linear-linear basis functions set to overcome the low-frequency breakdown of the Electric-field Integral Equation.

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    Novel self-loop basis functions for the stability of the Linear-linear discretization of the Electric Field Integral Equation at very low frequencies  Open access

     Tamayo Palau, Jose Maria; Ubeda Farre, Eduardo; Rius Casals, Juan-manuel
    IEEE International Symposium on Antennas and Propagation
    p. 2619-2622
    DOI: 10.1109/APS.2009.5172153
    Presentation's date: 2009-06
    Presentation of work at congresses

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    A self-loop basis functions is presented, a new set of solenoidal basis functions, which, together with the loop-star basis functions, define a rearrangement of the LL-discretization in method of moments of the EFIE that results in a stable impedance matrix at very low frequencies.

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    On the degrees of freedom in the interaction between sets of elementary scatterers  Open access

     Heldring, Alexander; Tamayo Palau, Jose Maria; Rius Casals, Juan-manuel
    European Conference on Antennas and Propagation
    p. 2413-2416
    Presentation's date: 2009-03
    Presentation of work at congresses

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    A series of numerical experiments has been executed to investigate the number of degrees of freedom in the interaction between large scattering bodies. The relation between degrees of freedom and operating frequency establishes the computational complexity for integral equation methods fast solvers based on matrix block compression. In 2D the theoretical asymptotic relation for large frequency soon becomes clear. On the other hand, in 3D even a tendency towards the asymptotic value fails to appear for bodies of hundreds of wavelengths in diameter.