Luis Diaz Angulo

Luis Diaz Angulo
University of Granada | UGR · Department of Electromagnetism and Matter Physics

Licenciado en Física

About

57
Publications
11,134
Reads
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524
Citations
Additional affiliations
March 2012 - present
University of Granada
Position
  • Electromagnetism
July 2008 - present
University of Granada
Position
  • Researcher
Education
October 2009 - September 2010
University of Granada
Field of study
  • Physics and Mathematics
January 2009 - November 2014
University of Granada
Field of study
  • Discontinuous Galerkin Methods for Maxwell Equations
October 2008 - February 2015
University of Granada
Field of study
  • Electronics

Publications

Publications (57)
Article
A new nodal hybrid continuous-discontinuous Galerkin time-domain (CDGTD) method for the solution of Maxwell's curl equations is proposed and analyzed. This hy-bridization is made by clustering small collections of elements with a continuous Galerkin (CG) formalism. These clusters exchange information with their exterior through a discontinuous Gale...
Article
Full-text available
Discontinuous Galerkin, applied to time-dependent Maxwell equations (DGTD), offers attractive properties when compared to other numerical methods. This method is flexible and accurate, like the finite element method, and efficient as well as scalable like finite-difference time-domain algorithms. In this letter, a new rigorous treatment of anisotro...
Article
We introduce a novel local time-stepping technique for marching-in-time algorithms. The technique is denoted as Causal-Path Local Time-Stepping (CPLTS) and it is applied for two time integration techniques: fourth order low--storage explicit Runge--Kutta (LSERK4) and second order Leapfrog (LF2). The CPLTS method is applied to evolve Maxwell's curl...
Article
Full-text available
Graphene-based devices constitute a pioneering field of research for their extraordinary electromagnetic properties. The incorporation of appropriate models into numerical simula-tors is necessary in order to take advantage of these properties. In this work, we propose a method to incorporate graphene-sheet models into the FDTD method. The use of v...
Article
Full-text available
The simulation of highly resonant structures requires techniques that are accurate and free of spurious-mode contamina-tion. Spurious modes can severely corrupt the solution of a phys-ical problem, and their suppression is a must for any numerical scheme in the frequency or in the time domain (TD). In this paper, we present the application of a hig...
Article
Full-text available
This work provides an in-depth computational performance study of the parallel finite-difference time-domain (FDTD) method. The parallelization is done at various levels including: shared- (OpenMP) and distributed- (MPI) memory paradigms and vectorization on three different architectures: Intel's Knights Landing, Skylake and ARM's Cavium ThunderX2....
Article
In this work, we use the finite differences in time domain (FDTD) numerical method to compute and assess the validity of Hopf solutions, or hopfions, for the electromagnetic field equations. In these solutions, field lines form closed loops characterized by different knot topologies which are preserved during their time evolution. Hopfions have bee...
Article
In the paper ”A new conformal FDTD for lossy thin panels” by M. R. Cabello et al., the appearance of spiky anti-resonances in the simulation of the shielding properties of lossy thin-shell spherical cavities by FDTD, was categorised as spurious solutions. In this document, we briefly clarify this topic, and show that these solutions are not really...
Preprint
Full-text available
In this work, we use the finite differences in time domain (FDTD) numerical method to compute and assess the validity of Hopf solutions, or hopfions, for the electromagnetic field equations. In these solutions, field lines form closed loops characterized by different knot topologies which are preserved during their time evolution. Hopfions have bee...
Article
We provide a model able to predict the shielding effectiveness (SE) of carbon fiber composite (CFC) panels made of stacked layers of conducting fibers. This model permits us to obtain simple formulas in which the only parameters needed are the sheet square resistance and the effective panel thickness. These tools let us predict a minimum SE, which...
Article
This paper presents an extension of the stochastic FDTD method to predict the standard deviation of currents and charges in the Holland FDTD sub-cell method for thin wires. A discussion is presented on the effect of cross-correlation between the variables affected by uncertainty, and the variability of the observed quantities. For this, a simple di...
Article
A novel conformal technique for the finite difference time domain (FDTD) method is proposed to deal with curved and arbitrarily oriented lossy thin panels. This is formulated as an extension of the existing conformal relaxed Dey-Mittra method (CRDM) combined with sub-cell algorithms to handle wave propagation across the panel. Two alternatives are...
Preprint
Full-text available
This paper develops a propagation model of electromagnetic signals emitted at frequencies of 20 and 40 [MHz] for the Ecuadorian jungle. It is expected that the results obtained at the end of this research will be applied to produce a complete coverage map for wireless communications technologies, which will optimize the radio electric spectrum in o...
Article
Full-text available
This paper analyzes the influence of simplifications in electromagnetic models used in the design of protections against High-Intensity Radiated Field (HIRF) threats. Both conductive and radiated effects are evaluated, covering the wide frequency range between 1 MHz and 6 GHz. A real and complex test case such as the power plant of an A400M aircraf...
Article
In a previous work, we presented a hybrid implicit-explicit Crank-Nicolson finite-difference time-domain (CN-FDTD) method for treating multilayered lossy thin slabs. The main advantage of this method was its capability to overcome certain late-time stability issues of conventional surface–impedance boundary condition (SIBC) approaches. In this pape...
Presentation
Full-text available
Colección de experimentos didácticos para realizar en el aula, junto con una introducción teórica, para la enseñanza de contenidos de electricidad, magnetismo y óptica.
Conference Paper
Full-text available
Se diseña y evalúa una experiencia de aula con Realidad Virtual Inmersiva para 1º ESO en relación al aprendizaje y enseñanza de la Tierra y el Sistema Solar en la materia de Biología-Geología. Con un diseño cuasi-experimental, se obtienen resultados positivos aunque no estadísticamente significativos.
Conference Paper
Full-text available
The simulators are pervasively used by the industry in the pre- manufacturing stages of a product. The ultimate geometric description in the final simulation is given by a mesh. Therefore, the achievement of precise, effi- cient, and powerfull meshing techniques are required by the simulator, in order to preserve the minimum necessary details but w...
Article
Full-text available
This paper discusses the influence of simplifications in models used in the design of electromagnetic protection against indirect effects of lightning strikes. A real and complex test case such as the power plant of an A400M aircraft, simulated with the FDTD method, is chosen for this. The parameters studied are the inclusion/removal of installatio...
Chapter
Electrical and electronic systems on board air vehicles are susceptible to electromagnetic interference (EMI). This has made the topic of electromagnetic compatibility (EMC), a major concern for aircraft safety. The use of composite materials worsens this situation, for their poor shielding and low conductive capabilities. Some of the main experime...
Article
In this paper, we show a simulation strategy for composite dispersive thin-panels, starting from their microscopic characteristics and ending into a time-domain macroscopic model. In a first part, we revisit different semianalytic methods that may be used to obtain the S-parameter matrices. The validity of them is assessed with numerical simulation...
Article
The increased use of carbon-fiber composites in unmanned aerial vehicles is a challenge for their EMC assessment by numerical solvers. For accurate and reliable simulations, numerical procedures should be tested not only for individual components, but also within the framework of complete systems. With this aim, this paper presents a benchmark test...
Article
The inclusion of thin lossy material layers, such as carbon-based composites, is essential for many practical applications for modeling the propagation of electromagnetic energy through composite structures such as those found in vehicles and electronic equipment enclosures. Many existing schemes suffer problems of late time instability, inaccuracy...
Article
Full-text available
This paper derives a multiresolution time-domain (MRTD) scheme for the multiconductor transmission line (MTL) equations based on Daubechies’ scaling functions. The terminations are characterized by a state-variable formulation which allows a general description of the termination networks. For the linear load terminations, a method incorporating th...
Article
A novel conformal technique for the FDTD method, here referred to as Conformal Relaxed Dey-Mittra method, is proposed and assessed in this letter. This technique helps avoid local time-step restrictions caused by irregular cells, thereby improving the global stability criterion of the original Dey-Mittra method. The approach retains a second-order...
Presentation
Full-text available
A presentation of the SEMBA problem type with special emphasis in the ZMesher module. A cartesian mesher aimed for FDTD.
Conference Paper
In this work we present a novel algorithm based on a subgridding boundary condition, for the subcell treatment of conductive thin-layer in FDTD (SGBC). We show that this technique provides a robust late-time stability behavior, compared to classical impedance boundary condition (IBC) methods, with affordable computer requirements. The method is val...
Article
As part of the technology research engaged in the EU Clean Sky 1 project, we present in this paper an electrical structure network (ESN) designed to prevent the impact on an electronic equipment of unwanted voltage drops appearing when nonmetal composite materials are used for grounding. An iterative process has been followed to reach an optimal tr...
Presentation
Full-text available
Basic usage tutorial of SEMBA Framework within GiD. A recording of the event can be watched at: https://www.youtube.com/watch?v=YgcnUhyIQp8
Research
Full-text available
This presentation shows applications of the SEMBA framework in the field of EMC. Initially developed for Airbus, it can deal with extremely complex geometries common in aeronautics, automotive industry, etc.
Research
Full-text available
Material didáctico sobre la temática de calendarios. Trabajo de Fin de Máster para el Máster Universitario en Profesorado de Enseñanza Secundaria Obligatoria y Bachillerato, Formación Profesional y Enseñanza de Idiomas.
Article
Full-text available
A n essential characteristic for the accurate simulation of wideband antenna systems is the modeling of their intricate geometrical details, including the feeding ports. In this article, we describe a leapfrog (LF) discontinuous Galerkin (DG) time-domain (TD) method combined with an efficient local time-stepping (LTS) strategy to deal with the high...
Article
Full-text available
This text reviews the state of the art of the Dis-continuous Galerkin (DG) method applied to the solution of the Maxwell's equations in Time Domain (TD). The work is divided into two parts. In the first part, the mathematical formulation of the DGTD method, together with a review and a discussion on the different ways to implement it is presented....
Conference Paper
Full-text available
This text reviews recent achievements made by the Electromagnetics Group of Granada (GEG) in the development of nodal Discontinuous Galerkin (DG) methods applied to the solution of the Maxwell’s equations in Time Domain (TD). The following techniques are reviewed in this work: an explicit Nodal Space-Time DG method, a Causal-Path Local Time Steppin...
Thesis
This dissertation presents a collection of academic works published or submitted for publication in scientific journals. It is composed of 14 chapters, each corresponding to an article, grouped in six different parts. The first part (Chapter 1) is a review of the state of the art of the Discontinuous Galerkin Time Domain (DGTD) method which is the...
Conference Paper
In this work, we show some characteristics than enable the efficient and accurate estimation of High-Intensity Radiated Fields transfer functions in complex environments by a leap-frog discontinuous Galerkin method. The conformal truncation of the computational domain, and the selection of different order of the basis functions combined with a loca...
Conference Paper
In this work we present a Discontinuous Galerkin Time Domain (DGTD) scheme, combined with a second-order Leap-Frog (LF2) time integrator, to solve Maxwell's equations. The dispersion and dissipation properties, together with an analysis of the computational costs of the method are investigated and compared with the classical Finite-Difference Time-...
Article
Full-text available
In this paper, we explore the accuracy limits of a finite-element time-domain (TD) method applied to the Maxwell equations, based on a discontinuous Galerkin scheme in space, and a leap-frog temporal integration. The dispersion and dissipation properties of the method are investigated, as well as the anisotropy of the errors. The results of this no...
Article
Full-text available
The simulation of low-observable targets requires high accuracy, both in the geometrical discretization as well as in the numerical solution of the electromagnetic problem. In this letter, we employ the well-known NASA almond to illustrate the accuracy of the leapfrog discontinuous Galerkin method, combined with a local time-stepping algorithm, com...
Conference Paper
Computer simulations provide invaluable information in HIRF (High Intensity Radiated Field) assessment of air vehicles. In this paper, we use a numerical model of a fictive metallic aircraft provided by EVEKTOR, to show a cross comparison of results found by some of the full-wave solvers developed by partners participating in the HIRF-SE project of...
Article
In this paper, we demonstrate the computational affordability and accuracy of a leap-frog discontinuous Galerkin (LFDG) time-domain method for high intensity radiated fields assessment in electromagnetic compatibility for aerospace. The conformal truncation of the computational domain is discussed and formulated in the LFDG context. Numerical valid...
Article
In the above letter (ibid., vol. 11, pp. 1182-1185, 2012), there is a missing author. The full list of authors should be J. Alvarez, Luis D. Angulo, A. Rubio Bretones, Carlos M. de Jong, and Salvador G. Garcia.
Article
Full-text available
In this paper we describe the discontinuous Galerkin time-domain method and apply it to the simu-lation of ground-penetrating radar (GPR) problems in 3D. The method is first validated with ana-lytical solutions and we show its superior behaviour when compared to the classical finite-differ-ence time-domain method, widely employed in GPR simulation....
Article
Full-text available
The classical Yee FDTD method has become a powerful tool in computational electromagnetics. Its application to EMC certification of aircrafts, under High Intensity Radiated Field (HIRF) conditions, is a current topic of interest in aerospace industry in order to reduce costs at the design stage. In this work, we present the details of a high perfor...
Article
Full-text available
We summarize the boundary and source implementation for the several formulations of the discontinuous Galerkin time domain method (DGTD). Since DGTD with zeroth-order scalar basis functions using the upwind flux, coincides with the finite volume time domain (FVTD), many of the concepts developed for FVTD can be ported to DGTD in any of its differen...
Conference Paper
This paper presents a time-domain numerical method to analyze photoconductive antennas operating in the terahertz regime. Theoretical basis of the formulation relies on the combination of the solutions of Poisson's equation, carrier-transport equations, and Maxwell's equations. Numerical results, achieved by employing finite-difference schemes, agr...
Article
Full-text available
Petri dishes of different types are widely used in bioelectromagnetic experiments for the assessment of the non-thermal biological effects of electromagnetic radiation. Two important qualities required for the experimental setups are to guarantee a sufficiently high level of exposure and to maintain uniformity of the fields affecting the cell cultu...
Article
Full-text available
The modeling of quasi-static optimization problems often involve divergence-free surface current densities. In this paper, a novel technique to implement these currents by using the boundary element method framework is presented. A locally–based characterization of the current density is employed, to render a fully geometry-independent formulation,...
Article
Full-text available
In this paper, we present a procedure to calculate the discrete modes propagated with Crank-Nicolson FDTD in metallic waveguides. This procedure enables the correct excitation of this kind of waveguides at any resolution. The problem is reduced to solving an eigenvalue equation, which is performed, both in a closed form, for the usual rectangular w...

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Projects (3)
Project
The impact of the electromagnetic environment upon the operational capability of aeronautic equipment, systems and platforms is known as electromagnetic environmental effects (E3). Their influence is becoming bigger in modern air platforms due to the increase of fly-by-wire systems in substitution of traditional mechanical options. Moreover, in the search of cost-effective approaches, notable parts of current aircraft are also being gradually made of composite materials (such as carbon fiber composite, CFC, aramid fibers, fiberglass, etc) and other even more innovative materials (doped rubber, graphene) are starting to be used for certain applications. Unmanned aerial vehicles (UAV), who have attracted the attention of manufacturers in the last two decades and have experienced a notorious development since are a particularly relevant example of aeronautic platforms with a high percentage of these kinds of materials. The electromagnetic performance of these non-metallic choices has to be assessed with respect to the aforementioned menaces. Consequently, in order to warrant the correct functioning of equipment, systems and platforms, the aeronautic industry is required to surpass different electromagnetic compatibility (EMC) certification processes based on military and aeronautic standards which traditionally rely on experimental testing. Bearing this in mind, the UAVE3 project aims to develop innovative, cost and time-effective analysis and testing methodologies integrating advanced electromagnetic modelling and simulation approaches, for use across the whole lifecycle of new generation composite UAV, including design, prototyping, certification, maintenance, overhaul and continuous airworthiness.