ANTENNALAB  Grup d'Antenes i Sistemes Radio
http://hdl.handle.net/2117/657
Fri, 28 Apr 2017 02:39:13 GMT
20170428T02:39:13Z

On the magnetic field integral equation discretized in linear triangles
http://hdl.handle.net/2117/103812
On the magnetic field integral equation discretized in linear triangles
Úbeda Farré, Eduard; Rius Casals, Juan Manuel; Parron, J; Cardama Aznar, Ángel
A formulation of the Method of Moments is presented for analyzing scattering problems involving three dimensional conductors. It is given an insight into the Magnetic Field Integral equation for which a triangle facet is used. It is shown the drawback of the MoMMFIE when compared with the MoMEFIE, particularly evident in sharpcornered
bodies of small electrical dimensions. It is introduced an alternative way to compute the solid angle that decreases the MoMMFIE RCS error. Some MoMMFIE RCS results on perfectly conducting electrically small cones, cubes and other polyhedrons are presented to confirm our solid angle choice.
Thu, 27 Apr 2017 17:44:58 GMT
http://hdl.handle.net/2117/103812
20170427T17:44:58Z
Úbeda Farré, Eduard
Rius Casals, Juan Manuel
Parron, J
Cardama Aznar, Ángel
A formulation of the Method of Moments is presented for analyzing scattering problems involving three dimensional conductors. It is given an insight into the Magnetic Field Integral equation for which a triangle facet is used. It is shown the drawback of the MoMMFIE when compared with the MoMEFIE, particularly evident in sharpcornered
bodies of small electrical dimensions. It is introduced an alternative way to compute the solid angle that decreases the MoMMFIE RCS error. Some MoMMFIE RCS results on perfectly conducting electrically small cones, cubes and other polyhedrons are presented to confirm our solid angle choice.

Analysis of reflector and horn antennas using multilevel fast multipole algorithm
http://hdl.handle.net/2117/103810
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
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 algorithm has been assessed by comparing
the results with the exact theoretical solution for a Perfectly Conducting Sphere. Subsequently
it has been applied to a parabolic reflector and and Xband horn, comparing the results with
measurements. Symmetric properties of the antennas have been exploited and an efficient
Incomplete LU preconditioner for the iterative solver has been applied.
Thu, 27 Apr 2017 17:24:14 GMT
http://hdl.handle.net/2117/103810
20170427T17:24:14Z
Heldring, Alexander
Rius Casals, Juan Manuel
Parrón Granados, Josep
Cardama Aznar, Ángel
Ligthart, L P
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 algorithm has been assessed by comparing
the results with the exact theoretical solution for a Perfectly Conducting Sphere. Subsequently
it has been applied to a parabolic reflector and and Xband horn, comparing the results with
measurements. Symmetric properties of the antennas have been exploited and an efficient
Incomplete LU preconditioner for the iterative solver has been applied.

Infrared thermograms applied to nearfield testing
http://hdl.handle.net/2117/103800
Infrared thermograms applied to nearfield testing
González Arbesú, José María; Aguasca Solé, Alberto; Blanch Boris, Sebastián; Romeu Robert, Jordi
Electromagnetic fields close to radiant structures can be measured quickly using an infrared camera. Examples of induced fields by wire antennas over a detection screen at distances shorter than one wavelength are presented. The measured thermograms agree with simulations that take into account heat propagation on the detection screen.
Thu, 27 Apr 2017 15:49:13 GMT
http://hdl.handle.net/2117/103800
20170427T15:49:13Z
González Arbesú, José María
Aguasca Solé, Alberto
Blanch Boris, Sebastián
Romeu Robert, Jordi
Electromagnetic fields close to radiant structures can be measured quickly using an infrared camera. Examples of induced fields by wire antennas over a detection screen at distances shorter than one wavelength are presented. The measured thermograms agree with simulations that take into account heat propagation on the detection screen.

Microwave imaging techniques for biomedical applications
http://hdl.handle.net/2117/103798
Microwave imaging techniques for biomedical applications
Joisel, A; Mallorquí Franquet, Jordi Joan; Broquetas Ibars, Antoni; Geffrin, J M; Joachimowicz, N; Vall·Llossera, M; VallLlossera Ferran, Mercedes Magdalena; Jofre Roca, Lluís; Bolomey, Jean Charles
Microwaves have been considered for medical applications involving the detection of organ movements and changes in tissue water content. More particularly cardiopulmonary interrogation via microwaves has resulted in various sensors monitoring ventricular volume change or movement, arterial wall motion, respiratory movements, pulmonary oedema, etc. In all these applications, microwave sensors perform local measurements and need to be displaced for obtaining an image reproducing the spatial variations of a given quantity. Recently, advances in the area of inverse scattering theory and microwave technology have made possible the development of microwave imaging and tomographic instruments. This paper provides a review of such equipment developed at Suplec and UPC Barcelona, within the frame of successive FrenchSpanish PICASSO cooperation programs. It reports the most significant results and gives some perspectives for future developments. Firstly, a brief historical survey is given. Then, both technological and numerical aspects are considered. The results of preliminary preclinical assessments and inlab experiments allow to illustrate the capabilities of the existing equipment, as well as its difficulty in dealing with clinical situations. Finally, some remarks on the expected development of microwave imaging techniques for biomedical applications are given.
Thu, 27 Apr 2017 15:39:03 GMT
http://hdl.handle.net/2117/103798
20170427T15:39:03Z
Joisel, A
Mallorquí Franquet, Jordi Joan
Broquetas Ibars, Antoni
Geffrin, J M
Joachimowicz, N
Vall·Llossera, M
VallLlossera Ferran, Mercedes Magdalena
Jofre Roca, Lluís
Bolomey, Jean Charles
Microwaves have been considered for medical applications involving the detection of organ movements and changes in tissue water content. More particularly cardiopulmonary interrogation via microwaves has resulted in various sensors monitoring ventricular volume change or movement, arterial wall motion, respiratory movements, pulmonary oedema, etc. In all these applications, microwave sensors perform local measurements and need to be displaced for obtaining an image reproducing the spatial variations of a given quantity. Recently, advances in the area of inverse scattering theory and microwave technology have made possible the development of microwave imaging and tomographic instruments. This paper provides a review of such equipment developed at Suplec and UPC Barcelona, within the frame of successive FrenchSpanish PICASSO cooperation programs. It reports the most significant results and gives some perspectives for future developments. Firstly, a brief historical survey is given. Then, both technological and numerical aspects are considered. The results of preliminary preclinical assessments and inlab experiments allow to illustrate the capabilities of the existing equipment, as well as its difficulty in dealing with clinical situations. Finally, some remarks on the expected development of microwave imaging techniques for biomedical applications are given.

Analysis of microstrip antennas by multilevel matrix decomposition algorithm
http://hdl.handle.net/2117/103715
Analysis of microstrip antennas by multilevel matrix decomposition algorithm
Parrón Granados, Josep; Rius Casals, Juan Manuel; Heldring, Alexander; Úbeda Farré, Eduard; Mosig, Juan R
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 due to the fact that the computational requirements increase rapidly with the number of unknowns N. Several techniques have been proposed to reduce the computational cost of IEMoM. The Multilevel Matrix Decomposition Algorithm (MLMDA) has been implemented in 3D for arbitrary perfectly conducting surfaces discretized in Rao, Wilton and Glisson linear triangle
basis functions . This algorithm requires an operation count that is proportional to N·log2N. The performance of the algorithm is much better for planar or piecewise planar objects than for general 3D problems, which makes the algorithm particularly wellsuited for the analysis of microstrip antennas. The memory requirements are proportional to N·logN and very low. The main advantage of the MLMDA compared with other efficient techniques to solve integral equations is that it does not rely on specific mathematical properties of the Green's functions being used. Thus, we can apply the method to interesting configurations governed by special Green's functions like multilayered media. In fact, the MDAMLMDA method can
be used at the top of any existing MoM code. In this paper we present the application to the analysis of large printed antenna arrays.
Tue, 25 Apr 2017 12:44:45 GMT
http://hdl.handle.net/2117/103715
20170425T12:44:45Z
Parrón Granados, Josep
Rius Casals, Juan Manuel
Heldring, Alexander
Úbeda Farré, Eduard
Mosig, Juan R
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 due to the fact that the computational requirements increase rapidly with the number of unknowns N. Several techniques have been proposed to reduce the computational cost of IEMoM. The Multilevel Matrix Decomposition Algorithm (MLMDA) has been implemented in 3D for arbitrary perfectly conducting surfaces discretized in Rao, Wilton and Glisson linear triangle
basis functions . This algorithm requires an operation count that is proportional to N·log2N. The performance of the algorithm is much better for planar or piecewise planar objects than for general 3D problems, which makes the algorithm particularly wellsuited for the analysis of microstrip antennas. The memory requirements are proportional to N·logN and very low. The main advantage of the MLMDA compared with other efficient techniques to solve integral equations is that it does not rely on specific mathematical properties of the Green's functions being used. Thus, we can apply the method to interesting configurations governed by special Green's functions like multilayered media. In fact, the MDAMLMDA method can
be used at the top of any existing MoM code. In this paper we present the application to the analysis of large printed antenna arrays.

Design of single shaped reflector antennas with a single feed applying genetic algorithms and graphical processing techniques
http://hdl.handle.net/2117/103593
Design of single shaped reflector antennas with a single feed applying genetic algorithms and graphical processing techniques
VallLlossera Ferran, Mercedes Magdalena; Rius Casals, Juan Manuel; García, M; Duffo Ubeda, Núria
A genetic algorithm GA has been de ( ) eloped for designing
singleshaped reflector antennas for the synthesis of shaped contour
beams. The graphical processing technique is used in order to obtain the
antenna radiation patterns ery efficiently. Results comparing with the
classical conjugate gradient are included to pro ide alidation. 2000
John Wiley & Sons, Inc. Microwave Opt Technol Lett 27: 358 361,
2000.
Thu, 20 Apr 2017 15:21:40 GMT
http://hdl.handle.net/2117/103593
20170420T15:21:40Z
VallLlossera Ferran, Mercedes Magdalena
Rius Casals, Juan Manuel
García, M
Duffo Ubeda, Núria
A genetic algorithm GA has been de ( ) eloped for designing
singleshaped reflector antennas for the synthesis of shaped contour
beams. The graphical processing technique is used in order to obtain the
antenna radiation patterns ery efficiently. Results comparing with the
classical conjugate gradient are included to pro ide alidation. 2000
John Wiley & Sons, Inc. Microwave Opt Technol Lett 27: 358 361,
2000.

Variations on the fractal Sierpinski antenna flare angle
http://hdl.handle.net/2117/103586
Variations on the fractal Sierpinski antenna flare angle
Puente Baliarda, Carles; Navarro Bernal, Manuel; Romeu Robert, Jordi; Pous Andrés, Rafael
A further investigation on the fractal multiband Sierpinski antenna is introduced. It is shown that a variation on the antenna's flare angle is translated into a shift of the operating bands, as well as into a change in the impedance level and radiation patterns. The contribution of those variations to the truncation effect is outlined.
Thu, 20 Apr 2017 14:30:33 GMT
http://hdl.handle.net/2117/103586
20170420T14:30:33Z
Puente Baliarda, Carles
Navarro Bernal, Manuel
Romeu Robert, Jordi
Pous Andrés, Rafael
A further investigation on the fractal multiband Sierpinski antenna is introduced. It is shown that a variation on the antenna's flare angle is translated into a shift of the operating bands, as well as into a change in the impedance level and radiation patterns. The contribution of those variations to the truncation effect is outlined.

Error bound of the multilevel adaptive cross approximation (MLACA)
http://hdl.handle.net/2117/102827
Error bound of the multilevel adaptive cross approximation (MLACA)
Chen, Xinlei; Gu, Changqing; Heldring, Alexander; Li, Zhuo; Cao, Qunsheng
An error bound of the multilevel adaptive cross approximation (MLACA 1, which is a multilevel version of the adaptive cross approximationsingular value decomposition (ACASVD), is rigorously derived. For compressing an offdiagonal submatrix of the method of moments MAD impedance matrix with a binary tree, the Llevel MIACA includes L + 1 steps, and each step includes 2(L) ACASVD decompositions. If the relative Frobenius norm error of the ACASVD used in the MLACA is smaller than epsilon, the rigorous proof in this communication shows that the relative Frobenius norm error of the LIevel MLACA is smaller than (1 + epsilon)(L+1)  1. In practical applications, the error bound of the MLACA can be approximated as epsilon(L + 1), because epsilon is always << 1. The error upper bound can he used to control the accuracy of the MLACA. To ensure an error of the Llevel MLACA smaller than epsilon for different L, the ACASVD threshold can be set to (1 + epsilon)1/L+1  1, which approximately equals epsilon/(L + 1) for practical applications.
Thu, 23 Mar 2017 13:25:21 GMT
http://hdl.handle.net/2117/102827
20170323T13:25:21Z
Chen, Xinlei
Gu, Changqing
Heldring, Alexander
Li, Zhuo
Cao, Qunsheng
An error bound of the multilevel adaptive cross approximation (MLACA 1, which is a multilevel version of the adaptive cross approximationsingular value decomposition (ACASVD), is rigorously derived. For compressing an offdiagonal submatrix of the method of moments MAD impedance matrix with a binary tree, the Llevel MIACA includes L + 1 steps, and each step includes 2(L) ACASVD decompositions. If the relative Frobenius norm error of the ACASVD used in the MLACA is smaller than epsilon, the rigorous proof in this communication shows that the relative Frobenius norm error of the LIevel MLACA is smaller than (1 + epsilon)(L+1)  1. In practical applications, the error bound of the MLACA can be approximated as epsilon(L + 1), because epsilon is always << 1. The error upper bound can he used to control the accuracy of the MLACA. To ensure an error of the Llevel MLACA smaller than epsilon for different L, the ACASVD threshold can be set to (1 + epsilon)1/L+1  1, which approximately equals epsilon/(L + 1) for practical applications.

From experimental campaigns to BEC  CP34 salinity products: Tribute to the Contributions of prof. Font to the SMOS Mission
http://hdl.handle.net/2117/102670
From experimental campaigns to BEC  CP34 salinity products: Tribute to the Contributions of prof. Font to the SMOS Mission
Camps Carmona, Adriano José; Gabarró Prats, Carolina; VallLlossera Ferran, Mercedes Magdalena; Blanch Boris, Sebastián; Aguasca Solé, Alberto; Torres Torres, Francisco; Corbella Sanahuja, Ignasi; Duffo Ubeda, Núria; Turiel, Antonio; Portabella, Marcos; BallabreraPoy, Joaquim; GonzálezGambau, Verónica; Martínez, Justino; Villarino Villarino, Ramon; Enrique, Luis; Monerris Belda, Sandra; Bosch, Xavier; Sabia, Roberto; Talone, Marco; Piles Guillem, Maria; Pablos Hernánez, Miriam; Valencia, Enric
This article summarizes some of the activities in which Jordi Font, research professor and head of the Department of Physical and Technological Oceanography, Institut de Ciències del Mar (CSIC, Spanish National Research Council) in Barcelona, has been involved as coPrincipal Investigator for Ocean Salinity of the European Space Agency Soil Moisture and Ocean Salinity (SMOS) Earth Explorer Mission from the perspective of the Remote Sensing Lab at the Universitat Politècnica de Catalunya. We have probably left out some of his many contributions to salinity remote sensing, but we hope that this review will give an idea of the importance of his work. We focus on the following issues: 1) the new accurate measurements of the sea water dielectric constant, 2) the WISE and EuroSTARRS field experiments that helped to define the geophysical model function relating brightness temperature to sea state, 3) the FROG 2003 field experiment that helped to understand the emission of sea foam, 4) GNSSR techniques for improving sea surface salinity retrieval, 5) instrument characterization campaigns, and 6) the operational implementation of the Processing Centre of Levels 3 and 4 at the SMOS Barcelona Expert Centre.
Mon, 20 Mar 2017 14:25:13 GMT
http://hdl.handle.net/2117/102670
20170320T14:25:13Z
Camps Carmona, Adriano José
Gabarró Prats, Carolina
VallLlossera Ferran, Mercedes Magdalena
Blanch Boris, Sebastián
Aguasca Solé, Alberto
Torres Torres, Francisco
Corbella Sanahuja, Ignasi
Duffo Ubeda, Núria
Turiel, Antonio
Portabella, Marcos
BallabreraPoy, Joaquim
GonzálezGambau, Verónica
Martínez, Justino
Villarino Villarino, Ramon
Enrique, Luis
Monerris Belda, Sandra
Bosch, Xavier
Sabia, Roberto
Talone, Marco
Piles Guillem, Maria
Pablos Hernánez, Miriam
Valencia, Enric
This article summarizes some of the activities in which Jordi Font, research professor and head of the Department of Physical and Technological Oceanography, Institut de Ciències del Mar (CSIC, Spanish National Research Council) in Barcelona, has been involved as coPrincipal Investigator for Ocean Salinity of the European Space Agency Soil Moisture and Ocean Salinity (SMOS) Earth Explorer Mission from the perspective of the Remote Sensing Lab at the Universitat Politècnica de Catalunya. We have probably left out some of his many contributions to salinity remote sensing, but we hope that this review will give an idea of the importance of his work. We focus on the following issues: 1) the new accurate measurements of the sea water dielectric constant, 2) the WISE and EuroSTARRS field experiments that helped to define the geophysical model function relating brightness temperature to sea state, 3) the FROG 2003 field experiment that helped to understand the emission of sea foam, 4) GNSSR techniques for improving sea surface salinity retrieval, 5) instrument characterization campaigns, and 6) the operational implementation of the Processing Centre of Levels 3 and 4 at the SMOS Barcelona Expert Centre.

Tangentialnormal surface testing for the nonconforming discretization of the electricfield integral equation
http://hdl.handle.net/2117/102423
Tangentialnormal surface testing for the nonconforming discretization of the electricfield integral equation
Úbeda Farré, Eduard; Sekulic, Ivan; Rius Casals, Juan Manuel; Heldring, Alexander
Nonconforming implementations of the electricfield integral equation (EFIE), based on the facetoriented monopolarRWG set, impose no continuity constraints in the expansion of the current between adjacent facets. These schemes become more versatile than the traditional edgeoriented schemes, based on the RWG set, because they simplify the management of junctions in composite objects and allow the analysis of nonconformal triangulations. Moreover, for closed moderately small conductors with edges and corners, they show improved accuracy with respect to the conventional RWGdiscretization. However, they lead to elaborate numerical schemes because the fields are tested inside the body, near the boundary surface, over volumetric subdomains attached to the surface meshing. In this letter, we present a new nonconforming discretization of the EFIE that results from
testing with RWG functions over pairs of triangles such that one triangle matches one facet of the surface triangulation and the other one is oriented perpendicularly, inside the body. This “tangentialnormal” testing scheme, based on surface integrals, simplifies considerably the matrix generation when compared to the volumetrically tested approaches.
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Tue, 14 Mar 2017 10:22:25 GMT
http://hdl.handle.net/2117/102423
20170314T10:22:25Z
Úbeda Farré, Eduard
Sekulic, Ivan
Rius Casals, Juan Manuel
Heldring, Alexander
Nonconforming implementations of the electricfield integral equation (EFIE), based on the facetoriented monopolarRWG set, impose no continuity constraints in the expansion of the current between adjacent facets. These schemes become more versatile than the traditional edgeoriented schemes, based on the RWG set, because they simplify the management of junctions in composite objects and allow the analysis of nonconformal triangulations. Moreover, for closed moderately small conductors with edges and corners, they show improved accuracy with respect to the conventional RWGdiscretization. However, they lead to elaborate numerical schemes because the fields are tested inside the body, near the boundary surface, over volumetric subdomains attached to the surface meshing. In this letter, we present a new nonconforming discretization of the EFIE that results from
testing with RWG functions over pairs of triangles such that one triangle matches one facet of the surface triangulation and the other one is oriented perpendicularly, inside the body. This “tangentialnormal” testing scheme, based on surface integrals, simplifies considerably the matrix generation when compared to the volumetrically tested approaches.