Ponències/Comunicacions de congressos
http://hdl.handle.net/2117/659
2017-05-05T05:07:33ZParche Sierpinksi Perturbado
http://hdl.handle.net/2117/103988
Parche Sierpinksi Perturbado
Borja Borau, Carmen; Romeu Robert, Jordi
The multiband behavior of the Sierpinski patch is described in this paper, and a new technique to improve such multiband behavior from the point of view of radiation patterns is also introduced.
2017-05-03T14:27:07ZBorja Borau, CarmenRomeu Robert, JordiThe multiband behavior of the Sierpinski patch is described in this paper, and a new technique to improve such multiband behavior from the point of view of radiation patterns is also introduced.Miniature Wideband stacked microstrip patch antenna based on the sierpinski fractal geometry
http://hdl.handle.net/2117/103982
Miniature Wideband stacked microstrip patch antenna based on the sierpinski fractal geometry
Romeu Robert, Jordi; Anguera Pros, Jaume; Puente Baliarda, Carles; Borja Borau, Carmen
The main interest in the design of a miniature microstrip patch antenna (MPA) is its small size in conjunction with the well-known advantages of a MPA (cost, profile, weight). However there is a big constraint on the bandwidth limitation either in a miniature antenna or in a MPA. The proposed solution to overcome such problem is to couple a miniature parasitic resonator to the miniature active patch forming a wideband small stacked microstrip patch antenna.
2017-05-03T13:49:59ZRomeu Robert, JordiAnguera Pros, JaumePuente Baliarda, CarlesBorja Borau, CarmenThe main interest in the design of a miniature microstrip patch antenna (MPA) is its small size in conjunction with the well-known advantages of a MPA (cost, profile, weight). However there is a big constraint on the bandwidth limitation either in a miniature antenna or in a MPA. The proposed solution to overcome such problem is to couple a miniature parasitic resonator to the miniature active patch forming a wideband small stacked microstrip patch antenna.Multiband Sierpinskl fractal patch antenna
http://hdl.handle.net/2117/103973
Multiband Sierpinskl fractal patch antenna
Borja Borau, Carmen; Romeu Robert, Jordi
The multiband behavior of the Sierpinski patch antenna is described, and a new technique to improve the multiband behavior from the point of view of the radiation patterns is introduced. The technique suppresses the effects of the high order modes and a patch antenna with similar radiation patterns can be designed. Once the high order mode has been suppressed for the second band, the next step is to try eliminate it for the third and fourth band breaking the appropriate junctions.
2017-05-03T12:46:46ZBorja Borau, CarmenRomeu Robert, JordiThe multiband behavior of the Sierpinski patch antenna is described, and a new technique to improve the multiband behavior from the point of view of the radiation patterns is introduced. The technique suppresses the effects of the high order modes and a patch antenna with similar radiation patterns can be designed. Once the high order mode has been suppressed for the second band, the next step is to try eliminate it for the third and fourth band breaking the appropriate junctions.Dual-band Sierpinski fractal monopole antenna
http://hdl.handle.net/2117/103910
Dual-band Sierpinski fractal monopole antenna
Romeu Robert, Jordi
A new top-loaded reduced-sized dual-band (1.9 GHz and 3.5 GHz) monopole antenna for wireless communications is presented. The antenna provides better than -15 dB input return loss and keeps the same radiation pattern over both bands. In addition, a low-profile performance is achieved.
2017-05-02T13:31:29ZRomeu Robert, JordiA new top-loaded reduced-sized dual-band (1.9 GHz and 3.5 GHz) monopole antenna for wireless communications is presented. The antenna provides better than -15 dB input return loss and keeps the same radiation pattern over both bands. In addition, a low-profile performance is achieved.High directivity modes in the koch island fractal patch antenna
http://hdl.handle.net/2117/103908
High directivity modes in the koch island fractal patch antenna
Romeu Robert, Jordi; Borja Borau, Carmen; Blanch Boris, Sebastián
The article shows that a patch antenna with fractal boundary exhibits, at a frequencies above the fundamental mode, localized modes. These modes can have broadside directive patterns. As an example of this phenomenon experimental data on the Koch island patch antenna is presented.
2017-05-02T13:21:39ZRomeu Robert, JordiBorja Borau, CarmenBlanch Boris, SebastiánThe article shows that a patch antenna with fractal boundary exhibits, at a frequencies above the fundamental mode, localized modes. These modes can have broadside directive patterns. As an example of this phenomenon experimental data on the Koch island patch antenna is presented.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 MoM-MFIE when compared with the MoM-EFIE, particularly evident in sharp-cornered
bodies of small electrical dimensions. It is introduced an alternative way to compute the solid angle that decreases the MoM-MFIE RCS error. Some MoM-MFIE RCS results on perfectly conducting electrically small cones, cubes and other polyhedrons are presented to confirm our solid angle choice.
2017-04-27T17:44:58ZÚbeda Farré, EduardRius Casals, Juan ManuelParron, JCardama Aznar, ÁngelA 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 MoM-MFIE when compared with the MoM-EFIE, particularly evident in sharp-cornered
bodies of small electrical dimensions. It is introduced an alternative way to compute the solid angle that decreases the MoM-MFIE RCS error. Some MoM-MFIE 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 X-band 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.
2017-04-27T17:24:14ZHeldring, AlexanderRius Casals, Juan ManuelParrón Granados, JosepCardama Aznar, ÁngelLigthart, L PThe 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 X-band 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 near-field testing
http://hdl.handle.net/2117/103800
Infrared thermograms applied to near-field 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.
2017-04-27T15:49:13ZGonzález Arbesú, José MaríaAguasca Solé, AlbertoBlanch Boris, SebastiánRomeu Robert, JordiElectromagnetic 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; Vall-Llossera 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 French-Spanish 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 pre-clinical assessments and in-lab 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.
2017-04-27T15:39:03ZJoisel, AMallorquí Franquet, Jordi JoanBroquetas Ibars, AntoniGeffrin, J MJoachimowicz, NVall·Llossera, MVall-Llossera Ferran, Mercedes MagdalenaJofre Roca, LluísBolomey, Jean CharlesMicrowaves 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 French-Spanish 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 pre-clinical assessments and in-lab 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 IE-MoM. 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 piece-wise planar objects than for general 3D problems, which makes the algorithm particularly well-suited 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 MDA-MLMDA 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.
2017-04-25T12:44:45ZParrón Granados, JosepRius Casals, Juan ManuelHeldring, AlexanderÚbeda Farré, EduardMosig, Juan RIntegral 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 IE-MoM. 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 piece-wise planar objects than for general 3D problems, which makes the algorithm particularly well-suited 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 MDA-MLMDA 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.