Ponències/Comunicacions de congressos
http://hdl.handle.net/2117/659
2016-10-26T20:04:02ZAnálisis de antenas de reflector mediante procesado gráfico
http://hdl.handle.net/2117/88574
Análisis de antenas de reflector mediante procesado gráfico
Vall-Llossera Ferran, Mercedes Magdalena; Salazar, C; Rius Casals, Juan Manuel; Cardama Aznar, Ángel
The aim of this article is to show a new technique for calculating the Radiation Pattern of arbitrary geometry reflector antennas. We use the Graphical processing technique developed in this group for Radar Cross Section Analysing [1] to obtain the whole geometry information of the reflector antenna necessary to obtain his radiation pattern. This program can obtain the first contribution using Phisical Optics technique, but also can obtain second order contribution.
2016-07-06T15:15:30ZVall-Llossera Ferran, Mercedes MagdalenaSalazar, CRius Casals, Juan ManuelCardama Aznar, ÁngelThe aim of this article is to show a new technique for calculating the Radiation Pattern of arbitrary geometry reflector antennas. We use the Graphical processing technique developed in this group for Radar Cross Section Analysing [1] to obtain the whole geometry information of the reflector antenna necessary to obtain his radiation pattern. This program can obtain the first contribution using Phisical Optics technique, but also can obtain second order contribution.Cálculo de radiación en 3 dimensiones mediante el método de los elementos de contorno
http://hdl.handle.net/2117/88569
Cálculo de radiación en 3 dimensiones mediante el método de los elementos de contorno
Duffo Ubeda, Núria; Rius Casals, Juan Manuel; Cardama Aznar, Ángel
In order to analize the electromagnetic fields generated by perfectly conducting bodies whichever it is its geometry, the Boundary Element Method is applied.
The basic formulation and associated items (integral equations to solve, surface and thin wire discretization, fields interpolation and numerical integration) are comented.
Results of problems of radiation are given and compared with available analytic solutions, which demostrate the good accurancy of the method.
2016-07-06T14:28:17ZDuffo Ubeda, NúriaRius Casals, Juan ManuelCardama Aznar, ÁngelIn order to analize the electromagnetic fields generated by perfectly conducting bodies whichever it is its geometry, the Boundary Element Method is applied.
The basic formulation and associated items (integral equations to solve, surface and thin wire discretization, fields interpolation and numerical integration) are comented.
Results of problems of radiation are given and compared with available analytic solutions, which demostrate the good accurancy of the method.Algoritmo iterativo de propagación espectral para el cálculo de RCS en cavidades conductoras
http://hdl.handle.net/2117/88568
Algoritmo iterativo de propagación espectral para el cálculo de RCS en cavidades conductoras
Rius Casals, Juan Manuel; Cardama Aznar, Ángel; Jofre Roca, Lluís
One of the most difficult problems in the RCS prediction of a complex target is the analysis of the cavities existing at the air inlets and outlets of engines. The geometrical complexity of these structures makes difficult the analysis by modal, ray or beam techniques, while their huge electrical size makes computationally prohibitive the analysis by matrix methods. For these reasons, we have developed an iterative spectral propagation algorithm which can be used to calculate the RCS of electrically intermediate or large cavities with certain geometrical features.
2016-07-06T14:15:41ZRius Casals, Juan ManuelCardama Aznar, ÁngelJofre Roca, LluísOne of the most difficult problems in the RCS prediction of a complex target is the analysis of the cavities existing at the air inlets and outlets of engines. The geometrical complexity of these structures makes difficult the analysis by modal, ray or beam techniques, while their huge electrical size makes computationally prohibitive the analysis by matrix methods. For these reasons, we have developed an iterative spectral propagation algorithm which can be used to calculate the RCS of electrically intermediate or large cavities with certain geometrical features.Caracterización electromagnética de materiales RAM mediante medidas en espacio libre
http://hdl.handle.net/2117/88567
Caracterización electromagnética de materiales RAM mediante medidas en espacio libre
Blanch Boris, Sebastián; Cardama Aznar, Ángel; Jofre Roca, Lluís
A free-space measurement system in the 2-JBGHz frequency range is used to measure the reflection and transmission coefficients of planar samples. The complex electric permittivity and the magnetic permeability are calculated from the measured values of S11 and S21. The measurement system consists of broadband transmit and receive antennas, a network analyzer, mode transitions, and a computer. Error due to multiple reflections between antennas via the swjace of the sample are corrected by using a free space T.R.L. calibration technique.
2016-07-06T14:06:32ZBlanch Boris, SebastiánCardama Aznar, ÁngelJofre Roca, LluísA free-space measurement system in the 2-JBGHz frequency range is used to measure the reflection and transmission coefficients of planar samples. The complex electric permittivity and the magnetic permeability are calculated from the measured values of S11 and S21. The measurement system consists of broadband transmit and receive antennas, a network analyzer, mode transitions, and a computer. Error due to multiple reflections between antennas via the swjace of the sample are corrected by using a free space T.R.L. calibration technique.Diseño de un alimentador primario para dos frecuencias y dos polarizaciones
http://hdl.handle.net/2117/87945
Diseño de un alimentador primario para dos frecuencias y dos polarizaciones
Ferrando Bataller, Miquel; Jofre Roca, Lluís
Primary feeds have been designed to operate simultaneously in two frecuency bands and two cross-polarizations. The multimode generalized scattering matrix has been used to characterize the circular waveguide discontinuity. Input impedance of coaxial line to circular waveguide feed has been computed.
2016-06-13T14:30:05ZFerrando Bataller, MiquelJofre Roca, LluísPrimary feeds have been designed to operate simultaneously in two frecuency bands and two cross-polarizations. The multimode generalized scattering matrix has been used to characterize the circular waveguide discontinuity. Input impedance of coaxial line to circular waveguide feed has been computed.Algoritmos de tomografía de microondas para objetos de alto contrastre
http://hdl.handle.net/2117/87936
Algoritmos de tomografía de microondas para objetos de alto contrastre
Broquetas Ibars, Antoni; Ferrando Bataller, Miquel; Jofre Roca, Lluís
Conventional first order algorithms used in microwave tomography often fail to reconstruct biological bodies due to their high contrast in permittivity. The paper presents several methods to improve the applicability of the algorithms and new reconstruction procedures suitable to high diffracting bodies, using optimization, frequency diversity, analytical continuation and matched plane wave synthesis techniques. The validity of the proposed algorithms is investigated by numerical simulations and experimentally.
2016-06-13T14:07:54ZBroquetas Ibars, AntoniFerrando Bataller, MiquelJofre Roca, LluísConventional first order algorithms used in microwave tomography often fail to reconstruct biological bodies due to their high contrast in permittivity. The paper presents several methods to improve the applicability of the algorithms and new reconstruction procedures suitable to high diffracting bodies, using optimization, frequency diversity, analytical continuation and matched plane wave synthesis techniques. The validity of the proposed algorithms is investigated by numerical simulations and experimentally.Formación de imagen por microondas mediante agrupamientos lineales ortogonales
http://hdl.handle.net/2117/87931
Formación de imagen por microondas mediante agrupamientos lineales ortogonales
Jofre Roca, Lluís; Ferrando Bataller, Miquel; Bolomey, Jean Charles
Capabilities of a microwave imaging system working in the air by using two crossed linear arrays are described. The analytic expressions of the focalization procedures are derived and resolution and available volume of reconstruction are discussed. Finally, some experimental images corresponding to two dielectric objects are also shown.
2016-06-13T13:45:53ZJofre Roca, LluísFerrando Bataller, MiquelBolomey, Jean CharlesCapabilities of a microwave imaging system working in the air by using two crossed linear arrays are described. The analytic expressions of the focalization procedures are derived and resolution and available volume of reconstruction are discussed. Finally, some experimental images corresponding to two dielectric objects are also shown.Análisis y medida en campo próximo de antenas parabólicas
http://hdl.handle.net/2117/87929
Análisis y medida en campo próximo de antenas parabólicas
Jofre Roca, Lluís; Ferrando Bataller, Miquel
A complet process of design and measurement of parabolic antennas, is presented. We have implemented a set of programs in order to design and analyze the different geometries of parabolic reflectors.
The measurements are made on a near field cylindrical system. Finally the most recent studies on antenna metrology and the definition of a semicompact cylindrical field are shown.
2016-06-13T13:41:19ZJofre Roca, LluísFerrando Bataller, MiquelA complet process of design and measurement of parabolic antennas, is presented. We have implemented a set of programs in order to design and analyze the different geometries of parabolic reflectors.
The measurements are made on a near field cylindrical system. Finally the most recent studies on antenna metrology and the definition of a semicompact cylindrical field are shown.Cálculo del campo difractado por objetos cilíndricos metálicos o multidieléctricos al incidir sobre ellos una onda
http://hdl.handle.net/2117/87926
Cálculo del campo difractado por objetos cilíndricos metálicos o multidieléctricos al incidir sobre ellos una onda
Ferrando Bataller, Miquel; Jofre Roca, Lluís
A method is described for calculating the scattered fields from conducting bodies and concentric multilayered cylinders, when they are illuminated by a wave with no z-axis variation. The method is based upon descomposition of a vawe in a cylindrical wave series centered in the object, so that contour conditions can be applied.
The exact scattered fields are calculated via Fast Fourier Transform routines. A generalisation of the method can lead to computation of fields scattered by separated single cylinders and cylinders containing non-concentric cylinders.
2016-06-13T13:35:29ZFerrando Bataller, MiquelJofre Roca, LluísA method is described for calculating the scattered fields from conducting bodies and concentric multilayered cylinders, when they are illuminated by a wave with no z-axis variation. The method is based upon descomposition of a vawe in a cylindrical wave series centered in the object, so that contour conditions can be applied.
The exact scattered fields are calculated via Fast Fourier Transform routines. A generalisation of the method can lead to computation of fields scattered by separated single cylinders and cylinders containing non-concentric cylinders.Receptor coherente para imágenes por microondas
http://hdl.handle.net/2117/87923
Receptor coherente para imágenes por microondas
de los Reyes, Elías; Jofre Roca, Lluís; Ferrando Bataller, Miquel
In order to avoid heating in the microwave imaging of biological bodies a very high sensitivity is needed for the receiver. We present a low cost sensitive coherent microwave receiver in microstrip technology.
2016-06-13T12:41:22Zde los Reyes, ElíasJofre Roca, LluísFerrando Bataller, MiquelIn order to avoid heating in the microwave imaging of biological bodies a very high sensitivity is needed for the receiver. We present a low cost sensitive coherent microwave receiver in microstrip technology.