Now showing items 1-20 of 59

    • A microwave invisibility cloak: the design, simulation, and measurement of a simple and effective frequency-selective surface-based mantle cloak 

      Yuste, Pedro; Rius Casals, Juan Manuel; Romeu Robert, Jordi; Blanch Boris, Sebastián; Heldring, Alexander; Úbeda Farré, Eduard (2018-06-26)
      Article
      Open Access
      In recent years, there has been a growing interest in developing invisibility cloaks that can conceal an object. These techniques are often based either on coating a dielectric or conducting object with a homogeneous ...
    • A recursive acceleration technique for static potential Green's functions of a rectangular cavity combining image and modal series 

      Tamayo Palau, José María; López-Peña, Sergio; Mattes, Michael; Heldring, Alexander; Rius Casals, Juan Manuel; Mosig, Juan Ramón (2011-03)
      Article
      Restricted access - publisher's policy
      A hybrid acceleration algorithm for the computation of the static potential Green’s functions of a rectangular cavity is proposed. Similarly to Ewald’s method, it combines the series expansions in terms of images and modes. ...
    • A simple and effective microwave invisibility cloak based on frequency selective surfaces 

      Yuste, Pedro; Rius Casals, Juan Manuel; Romeu Robert, Jordi; Blanch Boris, Sebastián; Heldring, Alexander; Úbeda Farré, Eduard (Institute of Electrical and Electronics Engineers (IEEE), 2017)
      Conference lecture
      Open Access
      This paper presents the design, simulation, manufacturing and testing of a simple invisibility cloak based on a frequency selective surface (FSS). The work is focused on cloaking an electrically thin dielectric cylinder ...
    • Accelerated direct solution of the method-of-moments linear system 

      Heldring, Alexander; Tamayo, J.M.; Úbeda Farré, Eduard; Rius Casals, Juan Manuel (2012-08)
      Article
      Restricted access - publisher's policy
      This paper addresses the direct (noniterative) solution of the method-of-moments (MoM) linear system, accelerated through block-wise compression of the MoM impedance matrix. Efficient matrix block compression is achieved ...
    • Accelerated direct solution of the MoM linear system using block compression and nested factorization 

      Heldring, Alexander; Rius Casals, Juan Manuel (IEEE, 2011)
      Conference report
      Restricted access - publisher's policy
      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), ...
    • Accelerated direct solution of the MoM-VIE for dielectric scatterers 

      Heldring, Alexander; Tamayo Palau, José María; Rius Casals, Juan Manuel; Úbeda Farré, Eduard (2011)
      Conference report
      Open Access
      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 ...
    • Acceleration of Born series by change of variables 

      López Menchón, Héctor; Rius Casals, Juan Manuel; Heldring, Alexander; Úbeda Farré, Eduard (2021-02-26)
      Article
      Open Access
      In this work, we propose a method to enhance the convergence of the Born series. The Born series is widely used in scattering theory, but its convergence is only guaranteed under certain restrictive conditions which limit ...
    • Accurate numerical modeling of the TARA reflector system 

      Heldring, Alexander; Rius Casals, Juan Manuel; Ligthart, Leo P.; Cardama Aznar, Ángel (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2004-07-31)
      Article
      Open Access
      The radiation pattern of the large parabolic reflectors of the Transportable Atmospheric RAdar system (TARA), developed at Delft University of Technology, has been accurately simulated. The electric field integral ...
    • Accurate, grid-robust and versatile combined-field discretization for the electromagnetic scattering analysis of perfectly conducting targets 

      Úbeda Farré, Eduard; Sekulic, Ivan; Rius Casals, Juan Manuel; Heldring, Alexander (2020-04-15)
      Article
      Restricted access - publisher's policy
      Recent implementations of the Electric-Field Integral Equation (EFIE) for the electromagnetic scattering analysis of perfectly conducting targets rely on the electric current expansion with the monopolar-RWG basis functions, ...
    • Adapted ACA algorithm with improved efficiency and compression rate 

      Heldring, Alexander; Úbeda Farré, Eduard; Rius Casals, Juan Manuel (2015)
      Conference report
      Open Access
      This contribution proposes an adapted version of the popular Adaptive Cross Approximation algorithm for block wise compression of Method of Moments impedance matrices. The estimation of the matrix block ...
    • Analysis of microstrip antennas by multilevel matrix decomposition algorithm 

      Parrón Granados, Josep; Rius Casals, Juan Manuel; Heldring, Alexander; Úbeda Farré, Eduard; Mosig, Juan R (ESA, 1999)
      Conference report
      Open Access
      Integral equation methods (IE) are widely used in conjunction with Method of Moments (MoM) discretization for the numerical analysis of microstrip antennas. However, their application to large antenna arrays is difficult ...
    • Analysis of reflector and horn antennas using multilevel fast multipole algorithm 

      Heldring, Alexander; Rius Casals, Juan Manuel; Parrón Granados, Josep; Cardama Aznar, Ángel; Ligthart, L P (CIMNE, 2000)
      Conference report
      Open Access
      The MultiLevel Fast Multipole Algorithm (MLFMA) has been implemented in a Method of Moments code for arbitrarily shaped metal surfaces discretized in Rao, Wilton and Glisson (RWG) basisfunctions. The accuracy of the ...
    • Application of Multilevel Adaptive Cross Approximation (MLACA) to electromagnetic scattering and radiation problems 

      Tamayo Palau, José María; Heldring, Alexander; Rius Casals, Juan Manuel (2009-09-14)
      Conference report
      Open Access
    • Compression of the MoM matrix using macrobasis functions with a full-controlable accuracy 

      Tamayo Palau, José María; Heldring, Alexander; Rius Casals, Juan Manuel (EurAPP, 2009)
      Conference report
      Open Access
      A new accuracy-controlable method for compressing the MoM impedance matrix of an electromagnetic problem based on a basis change plus a truncation with a threshold is presented here. The idea is to switch to singular basis ...
    • Creació de recursos en línea per a l’autoaprenentage, foment de l’esperit crític i emprenedor i formació d’un comité d’avaluació externa en el màster MERIT 

      Pradell i Cara, Lluís; Cabrera-Bean, Margarita; Canal Bienzobas, Fernando; Cardama Aznar, Ángel; Gasull Llampallas, Antoni; González Arbesú, José María; Giró Nieto, Xavier; Heldring, Alexander; Herranz Luis, Jaime; Jofre Roca, Lluís; Mallorquí Franquet, Jordi Joan; Nadeu Camprubí, Climent; Olmos Bonafé, Juan José; Romeu Robert, Jordi; Rius Casals, Juan Manuel; Torres Torres, Francisco; Úbeda Farré, Eduard; Coderch Collell, Marcel; Kerans, Mary Ellen; Ros Giralt, Jordi; García, Antonio; González Font, Blanca; Guardiola Garcia, Marta; Hernández, Antoni; Melgarejo, Natali; Mestres, Albert (2009-02-12T10:25:51Z)
      Conference lecture / Conference report
      Open Access
      El projecte es desenvolupa en el marc de la titulació oficial de màster MERIT del Departament de Teoria del Senyal i Comunicacions. El màster, orientat a la recerca i integrat dins del programa Erasmus Mundus, presenta ...
    • Discretization of the EFIE in Method of Moments without continuity of the normal current component across edges 

      Úbeda Farré, Eduard; Rius Casals, Juan Manuel; Heldring, Alexander (Institute of Electrical and Electronics Engineers (IEEE), 2013)
      Conference report
      Restricted access - publisher's policy
      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 ...
    • Edge diffraction computation using GRECO 

      Rius Casals, Juan Manuel; Carbo, Alex; Úbeda Farré, Eduard; Heldring, Alexander (Institute of Electrical and Electronics Engineers (IEEE), 2016)
      Conference report
      Restricted access - publisher's policy
      This paper addresses two graphical processing approaches for computation of edge scattering with Physical Theory of Diffraction (PTD) high-frequency approximation. One is based on processing only a bitmap containing an ...
    • Efficient analysis of homogeneous dielectric and plasmonic media with integral equation MEI (IE-MEI) 

      Rius Casals, Juan Manuel; Planes Conangla, Gerard; Úbeda Farré, Eduard; Heldring, Alexander (Institute of Electrical and Electronics Engineers (IEEE), 2015)
      Conference lecture
      Restricted access - publisher's policy
      This paper revisits the IE-MEI method and proposes a new formulation for high-loss dielectric piecewise-homogeneous media. The aim of this work is to assess if the fast attenuation of fields in highly lossy media helps in ...
    • Efficient computation of the effect of wire ends in thin wire analysis 

      Heldring, Alexander; Úbeda Farré, Eduard; Rius Casals, Juan Manuel (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2006-10-31)
      Article
      Open Access
      Computationally efficient algorithms are presented for the computation of the effect of flat wire ends (end caps) in the common thin wire model. A uniform charge distribution over the surface of the end cap is assumed, and ...
    • Error bound of the multilevel adaptive cross approximation (MLACA) 

      Chen, Xinlei; Gu, Changqing; Heldring, Alexander; Li, Zhuo; Cao, Qunsheng (2016-01)
      Article
      Open Access
      An error bound of the multilevel adaptive cross approximation (MLACA 1, which is a multilevel version of the adaptive cross approximation-singular value decomposition (ACA-SVD), is rigorously derived. For compressing an ...