Person: Sebastián Franco, José Luis
Universidad Complutense de Madrid
Faculty / Institute
Now showing 1 - 10 of 29
PublicationModelling the internal field distribution in human erythrocytes exposed to MW radiation(Elsevier Science SA, 2004-08) Sebastián Franco, José Luis; Muñoz San Martín, Sagrario; Sancho Ruíz, Miguel; Miranda Pantoja, José MiguelThis paper studies the internal electric field distribution in human erythrocytes exposed to MW radiation. For this purpose, an erythrocyte cell model is exposed to linearly polarized electromagnetic (EM) plane waves of frequency 900 MHz and the electric field within the cell is calculated by using a finite element (FE) technique with adaptive meshing. The results obtained show the dependence of the induced electric field distribution on the main modelling parameters, i.e., the electrical properties (permittivity and conductivity) of the membrane and cytoplasm and the orientation of the cell with respect to the applied field. It is found that for certain orientations, the field amplification within the membrane of the erythrocyte shape cell can be higher than the one observed in an equivalent simple spheroidal geometry cell, commonly used in bioelectromagnetism. The present work shows that a better insight of the interaction of electromagnetic fields with basic biological structures is obtained when the most possible realistic cell shape is used. (C) 2004 Elsevier B.V. All rights reserved. PublicationAnalysis of the electric field induced forces in erythrocyte membrane pores using a realistic cell model(IOP Publishing Ltd, 2006-12-07) Sebastián Franco, José Luis; Muñoz San Martín, Sagrario; Sancho Ruíz, Miguel; Miranda Pantoja, José MiguelWe calculate the induced electric stress forces on transient hydrophobic pores in the membrane of an erythrocyte exposed to an electric field. For this purpose, we use a finite element numerical technique and a realistic shape for the biconcave erythrocyte represented by a set of parametric equations in terms of Jacobi elliptic functions. The results clearly show that the electrical forces on the base and sidewalls of the pore favour the opening of the pore. A comparison of the force densities obtained for an unstretched flat membrane and for the realistic erythrocyte model shows that the thinning and curvature of the membrane cannot be neglected. We also show that the pore deformation depends strongly on the orientation of the pore with respect to the external field, and in particular is very small when the field is tangent to the membrane surface. PublicationTransmembrane voltage induced on altered erythrocyte shapes exposed to RF fields(Wiley-Liss, 2004-12) Muñoz San Martín, Sagrario; Sebastián Franco, José Luis; Sancho Ruíz, Miguel; Miranda Pantoja, José MiguelIn this article, the transmembrane voltage induced on erythrocyte, codocyte, ovalocyte and spherocyte cell models exposed to a linearly polarised electromagnetic plane wave of frequency 1800 MHz is calculated. For this purpose, a finite element (FE) numerical technique with adaptive meshing is used. The results show that the value of the induced voltage on the original erythrocyte shape is higher than the one observed on the rest of the altered cell geometries studied. The erythrocyte shape and the membrane electric permittivity are shown to play a fundamental role on the values of the induced transmembrane voltage. Bioelectromagnetics 25:631-633, 2004. (C) 2004 Wiley-Liss, Inc. PublicationMonte Carlo simulation of microwave noise temperature in cooled GaAs and InP(IEEE-Inst. Electrical Electronics Engineers Inc, 2000-07) Miranda Pantoja, José Miguel; Sebastián Franco, José LuisA simulation at microscopic level of the intrinsic microwave noise temperature associated to GaAs and InP semiconductors under far from equilibrium conditions has been performed. The dependence of the noise temperature on the electric field, doping level, and physical temperature has been investigated, and the results show the existence of threshold fields above which electron heating and partition noise due to intervalley scattering can make the cooling inefficient in terms of noise improvements. A comparison with available experimental data has also been made to verify the accuracy of the models used in the simulation. PublicationNoise performance of submicron HEMT channels under low power consumption operation(IEEE, 2000) Miranda Pantoja, José Miguel; Sebastián Franco, José LuisWe have investigated the noise performance of HEMT devices for low noise operation with the aim of developing a noise model valid for low power biasing. Analytical expressions useful for CAD models have been derived for the calculation of the Pospieszalski gate and drain temperatures, and have been verified from near pinchoff conditions up to usual bias voltages. An overshoot in the drain temperature as a function of the drain voltage has been observed at low drain currents in deep submicron gate lenght devices. PublicationAccuracy of nonoscillating one-port noise measurements(IEEE-Inst Electrical Electronics Engineers Inc, 1995-08) Miranda Pantoja, José Miguel; Sebastián Franco, José LuisThis paper presents a detailed analysis of the accuracy of nonoscillating one-port device noise measurements. A new expression is given for the calculation of the noise temperature from parameters that can be measured directly by using either a power sensor or a noise meter with the capability of making power measurements. A general expression for the DUT noise temperature error function is also obtained, which enables the authors to study how the noise measurement accuracy is affected by a number of different factors. This expression has been found very useful in order to study how the accuracy can be improved in a given noise measurement system. The error function has been applied to evaluate the uncertainty of Schottky barrier device noise measurements. PublicationInternacionalización de las prácticas de laboratorio en las asignaturas del área de Electromagnetismo del grado de Ingeniería Electrónica(2018-10-15) Miranda Pantoja, José Miguel; Antoranz Canales, Pedro; Muñoz San Martín, Sagrario; Tejedor Álvarez, Luis Ángel; Sebastián Franco, José Luis; Díaz Gómez, Leonardo; Serna Galán, Julio; Herrera Fernández, Fernando; Villarín Rosales, Álvaro; Sánchez Ávila, Mario; Cereceda Arias, Marcos; Teba Baeza, Pedro Miguel; Fernández Rodríguez, Pablo; Oliver García, ClaraEn esta memoria se describen los resultados del proyecto num 122, "Internacionalización de las prácticas de laboratorio en las asignaturas del área de Electromagnetismo del grado de Ingeniería Electrónica". Se han realizado más de veinte vídeos divulgativos en ingles sobre las técnicas experimentales que se estudian en las asignaturas del Área de Electromagnetismo de la Ingeniería Electrónica de Comunicaciones. Estos vídeos se han cargado en un canal de Youtube, al que se puede acceder desde la página web www.ucm.es/elec. PublicationErythrocyte rouleau formation under polarized electromagnetic fields(American Physical Society, 2005-09) Sebastián Franco, José Luis; Muñoz San Martín, Sagrario; Sancho Ruíz, Miguel; Miranda Pantoja, José Miguel; Álvarez Galindo, GabrielWe study the influence of an external electromagnetic field of 1.8 GHz in the formation or disaggregation of long rouleau of identical erythrocyte cells. In particular we calculate the variation of the transmembrane potential of an individual erythrocyte illuminated by the external field due to the presence of the neighboring erythrocytes in the rouleau, and compare the total electric energy of isolated cells with the total electric energy of the rouleau. We show that the polarization of the external electromagnetic field plays a fundamental role in the total energy variation of the cell system, and consequently in the formation or disaggregation of rouleau. PublicationMonte Carlo simulation of electron velocity in degenerate GaAs(IEEE- Inst. Electrical Electronics Engineers Inc, 1997-06) Miranda Pantoja, José Miguel; Sebastián Franco, José LuisA calculation of the electron velocity in heavily doped GaAs has been performed. A model to account for the LO phonon-plasmon coupling effects is proposed in a full Monte Carlo simulator; we believe this is the first time this fact has been tried out, Nonequilibrium screening effects are considered in the simulation. The Pauli exclusion principle is extended to the hot electron regime by the use of the electron temperature, which is calculated self consistently from the mean energy, A direct comparison with experimental velocities is made to show the accuracy of the simulation at both 77 and 300 K. Comparisons with simpler Monte Carlo models are also presented to illustrate the influence of the different effects considered in this letter. PublicationCharacterization of parasitics in microwave devices by comparing S and noise parameter measurements with two different on wafer calibration techniques(IEEE, 2001) Miranda Pantoja, José Miguel; Muñoz San Martín, Sagrario; Sebastián Franco, José LuisThis paper presents a procedure for an accurate characterization of parasitic effects of terminal pads in microwave devices. This procedure is based on the measurement of S and Noise parameters of the device with two different sets of calibration standards, and simplifies the process of extracting the parasitic elements of the small signal equivalent circuit.