http://hdl.handle.net/2117/657 Thu, 23 May 2013 01:51:02 GMT 2013-05-23T01:51:02Z webmaster.bupc@upc.edu Universitat Politècnica de Catalunya. Servei de Biblioteques i Documentació no http://hdl.handle.net/2117/19341 Title: Real time 100 GHz MST imaging retina Authors: Alonso del Pino, María; Garg, V.; Garcia Guerra, Carlos Enrique; Romeu Robert, Jordi; Llombart, Nuria; Jofre Roca, Lluís Abstract: A real time tomographic imaging system at 100 GHz based on a retina and Modulated Scattered Technique (MST) is presented in this paper. It consists in applying a low frequency modulation to each probe of an array of antennas in order to coherently detect the electric field by a collector. This system just requires low frequency wiring and reduces the RF equipment necessary for each pixel for a planar surface. The aim of this paper is to analyze the performance of different tomographic imaging processes for the imaging system described. Fri, 17 May 2013 13:52:47 GMT http://hdl.handle.net/2117/19341 2013-05-17T13:52:47Z Alonso del Pino, María; Garg, V.; Garcia Guerra, Carlos Enrique; Romeu Robert, Jordi; Llombart, Nuria; Jofre Roca, Lluís no antenna design, imaging reconstruction, imaging system, MST, Real time, Retina, THz, tomography A real time tomographic imaging system at 100 GHz based on a retina and Modulated Scattered Technique (MST) is presented in this paper. It consists in applying a low frequency modulation to each probe of an array of antennas in order to coherently detect the electric field by a collector. This system just requires low frequency wiring and reduces the RF equipment necessary for each pixel for a planar surface. The aim of this paper is to analyze the performance of different tomographic imaging processes for the imaging system described. http://hdl.handle.net/2117/19292 Title: MM-wave scattering measurements for imaging and channel characterization Authors: Toda, A.P.; de Flaviis, Franco; Jofre Roca, Lluís; Romeu Robert, Jordi Abstract: In this paper, mm-wave band scattering measurements are performed and imaging reconstructions obtained using a 2-D Scatterer Mapping Technique based on a Multi-Frequency Bi-Focusing operator (MF-BF). The measured data matrix is also processed to obtain its eigenvalues and eigenvectors. A relation between the eigenvalues and the number of scatterers and the eigenvectors and the scatterers spatial localization is obtained. Thu, 16 May 2013 12:23:28 GMT http://hdl.handle.net/2117/19292 2013-05-16T12:23:28Z Toda, A.P.; de Flaviis, Franco; Jofre Roca, Lluís; Romeu Robert, Jordi no imaging, Lens antenna, mm-wave, scatterer mapping, V-Band In this paper, mm-wave band scattering measurements are performed and imaging reconstructions obtained using a 2-D Scatterer Mapping Technique based on a Multi-Frequency Bi-Focusing operator (MF-BF). The measured data matrix is also processed to obtain its eigenvalues and eigenvectors. A relation between the eigenvalues and the number of scatterers and the eigenvectors and the scatterers spatial localization is obtained. http://hdl.handle.net/2117/19216 Title: Laboratori docent d'ones de radiació i ones guiades Authors: Cardama Aznar, Ángel; Mallorquí Franquet, Jordi Joan; Romeu Robert, Jordi; Torres Torres, Francisco Tue, 14 May 2013 16:46:47 GMT http://hdl.handle.net/2117/19216 2013-05-14T16:46:47Z Cardama Aznar, Ángel; Mallorquí Franquet, Jordi Joan; Romeu Robert, Jordi; Torres Torres, Francisco no http://hdl.handle.net/2117/18564 Title: Tomographic imaging retina at 100 GHz Authors: Alonso, Maria; Garg, V; Romeu Robert, Jordi; Llombart, Nuria; Jofre Roca, Lluís Abstract: This paper presents a tomographic system at 100 GHz for imaging based on MST technique. At 100 GHz, a good compromise is obtained between penetration and reso- lution for biomedical and non-destructive testing applications. Moreover, this system just requires low frequency wiring and reduces the RF equipment necessary for performing real-time imaging. The system has been built and successfully validated with a set of measurements for a canonical scenario. Wed, 03 Apr 2013 10:47:28 GMT http://hdl.handle.net/2117/18564 2013-04-03T10:47:28Z Alonso, Maria; Garg, V; Romeu Robert, Jordi; Llombart, Nuria; Jofre Roca, Lluís no This paper presents a tomographic system at 100 GHz for imaging based on MST technique. At 100 GHz, a good compromise is obtained between penetration and reso- lution for biomedical and non-destructive testing applications. Moreover, this system just requires low frequency wiring and reduces the RF equipment necessary for performing real-time imaging. The system has been built and successfully validated with a set of measurements for a canonical scenario. http://hdl.handle.net/2117/18563 Title: Optical cross-correlation of millimeter wave signals applied to interferometric radiometry Authors: Nova, Enrique; Romeu Robert, Jordi; Torres Torres, Francisco; Broquetas Ibars, Antoni; Jofre Roca, Lluís Abstract: This paper presents a method to perform in the opti- cal domain the correlations required when processing millimeter wave interferometric radiometer signals. The main problem when addressing the design of an interferometric radiometer working at W-band resides on the distribution and correlation of large bandwidth signals acquired by each radiometer receiver. In order to avoid the necessity of baseband processing of signals with large relative bandwidths, the signals coming from the radiometric receivers are up-converted to the optical domain using LiNbO3 optical phase modulators. The modulated signals from each receiver pairs are added and and detected by a photodiode. The correlation is obtained from the resulting photocurrent. Wed, 03 Apr 2013 10:43:31 GMT http://hdl.handle.net/2117/18563 2013-04-03T10:43:31Z Nova, Enrique; Romeu Robert, Jordi; Torres Torres, Francisco; Broquetas Ibars, Antoni; Jofre Roca, Lluís no This paper presents a method to perform in the opti- cal domain the correlations required when processing millimeter wave interferometric radiometer signals. The main problem when addressing the design of an interferometric radiometer working at W-band resides on the distribution and correlation of large bandwidth signals acquired by each radiometer receiver. In order to avoid the necessity of baseband processing of signals with large relative bandwidths, the signals coming from the radiometric receivers are up-converted to the optical domain using LiNbO3 optical phase modulators. The modulated signals from each receiver pairs are added and and detected by a photodiode. The correlation is obtained from the resulting photocurrent. http://hdl.handle.net/2117/18562 Title: UWB Magnitude combined realistic breast model imaging capabilities Authors: Guardiola Garcia, Marta; Jofre Roca, Lluís; Romeu Robert, Jordi Abstract: Breast cancer is the leading cancer killer among women. Early stage detection has been recognized to be best solution to reduce mortality rates. A non-ionizing, economical screening system based on microwave imaging is being investigated, but it is still a long way towards clinical ready system. In this paper, the validation of UWB-MC tomographic algorithm is performed using realistic breast models. Wed, 03 Apr 2013 10:38:48 GMT http://hdl.handle.net/2117/18562 2013-04-03T10:38:48Z Guardiola Garcia, Marta; Jofre Roca, Lluís; Romeu Robert, Jordi no Breast cancer is the leading cancer killer among women. Early stage detection has been recognized to be best solution to reduce mortality rates. A non-ionizing, economical screening system based on microwave imaging is being investigated, but it is still a long way towards clinical ready system. In this paper, the validation of UWB-MC tomographic algorithm is performed using realistic breast models. http://hdl.handle.net/2117/18561 Title: Retina design for 100GHz MST imaging system Authors: Alonso, Maria; Garg, V.; Nova, Enrique; Abril, Jordi; Romeu Robert, Jordi; Llombart, Nuria; Jofre Roca, Lluís Abstract: A near field imaging system for THz tomographic imaging based on a MST retina (an array of real antennas) has been designed. The main adva ntage of this implementation is the absence of microwave transmission line distribution networks and the capability to perform high speed imaging. The aim of this paper is to describe the design of the retina in order to maximize the performance of this im aging system. Wed, 03 Apr 2013 10:32:05 GMT http://hdl.handle.net/2117/18561 2013-04-03T10:32:05Z Alonso, Maria; Garg, V.; Nova, Enrique; Abril, Jordi; Romeu Robert, Jordi; Llombart, Nuria; Jofre Roca, Lluís no A near field imaging system for THz tomographic imaging based on a MST retina (an array of real antennas) has been designed. The main adva ntage of this implementation is the absence of microwave transmission line distribution networks and the capability to perform high speed imaging. The aim of this paper is to describe the design of the retina in order to maximize the performance of this im aging system. http://hdl.handle.net/2117/18560 Title: Input impedance measurements of cell phone antennas using backscattering modulation Authors: Monsalve, Beatriz; Blanch Boris, Sebastián; Romeu Robert, Jordi Abstract: This contribution presents an overview of the backscattering modulation applied to input impedance measurements of cell phone antennas. Wed, 03 Apr 2013 10:28:47 GMT http://hdl.handle.net/2117/18560 2013-04-03T10:28:47Z Monsalve, Beatriz; Blanch Boris, Sebastián; Romeu Robert, Jordi no This contribution presents an overview of the backscattering modulation applied to input impedance measurements of cell phone antennas. http://hdl.handle.net/2117/18353 Title: Determination of the overlap factor and its enhancement for medium-size tropospheric lidar systems: a ray-tracing approach Authors: Kumar, Dhiraj; Rocadenbosch Burillo, Francisco Abstract: The problem of overlap factor (OVF) computation and its near-range sensitivity for medium-size aperture ( f ∕ 10 , f ∕ 11 ) bi-axial tropospheric lidar systems using ray-tracing sim- ulation software is presented. The method revisits both detector and fiber optics coupling alter- natives at the telescope focal-plane along with the insertion of a field lens. A sensitivity analysis is carried out as a function of laser divergence, field lens, and detector/fiber positions, detector size, and the fiber ’ s core diameter and numerical aperture. The ray-tracing approach presented here is straightforward and a comparatively much simpler solution than analytical-based meth- ods. Parametric simulations are carried out to show that both approaches are coincident. Insertion of a field lens proves to be an elegant and low sensitivity solution for OVF enhancement, par- ticularly, in the near-range of the lidar Fri, 15 Mar 2013 15:03:19 GMT http://hdl.handle.net/2117/18353 2013-03-15T15:03:19Z Kumar, Dhiraj; Rocadenbosch Burillo, Francisco no The problem of overlap factor (OVF) computation and its near-range sensitivity for medium-size aperture ( f ∕ 10 , f ∕ 11 ) bi-axial tropospheric lidar systems using ray-tracing sim- ulation software is presented. The method revisits both detector and fiber optics coupling alter- natives at the telescope focal-plane along with the insertion of a field lens. A sensitivity analysis is carried out as a function of laser divergence, field lens, and detector/fiber positions, detector size, and the fiber ’ s core diameter and numerical aperture. The ray-tracing approach presented here is straightforward and a comparatively much simpler solution than analytical-based meth- ods. Parametric simulations are carried out to show that both approaches are coincident. Insertion of a field lens proves to be an elegant and low sensitivity solution for OVF enhancement, par- ticularly, in the near-range of the lidar http://hdl.handle.net/2117/18318 Title: Interference rejection using frequency and pattern reconfigurable antennas Authors: Rodrigo López, Daniel; Romeu Robert, Jordi; Jofre Roca, Lluís Abstract: Interference rejection by taking advantage of the radiation pattern diversity of a reconfigurable antenna is considered. It is proposed to use simultaneously frequency and radiation reconfiguration to extend interference rejection capabilities to large bandwidths. A small-size low-complexity pixel antenna is used to provide interference rejection capabilities over an octave bandwidth. An average signal-to-interference ratio of 24 dB is achieved and interference rejections above 15 dB are reliably provided over the whole frequency bandwidth and an angular range of 120o Thu, 14 Mar 2013 17:40:20 GMT http://hdl.handle.net/2117/18318 2013-03-14T17:40:20Z Rodrigo López, Daniel; Romeu Robert, Jordi; Jofre Roca, Lluís no Interference rejection by taking advantage of the radiation pattern diversity of a reconfigurable antenna is considered. It is proposed to use simultaneously frequency and radiation reconfiguration to extend interference rejection capabilities to large bandwidths. A small-size low-complexity pixel antenna is used to provide interference rejection capabilities over an octave bandwidth. An average signal-to-interference ratio of 24 dB is achieved and interference rejections above 15 dB are reliably provided over the whole frequency bandwidth and an angular range of 120o http://hdl.handle.net/2117/18172 Title: Sparsified ACA for accelerated iterative solution of the MoM linear system Authors: Heldring, Alexander; Rius Casals, Juan Manuel; Úbeda Farré, Eduard; Tamayo Palau, José María Abstract: A new algorithm, the Sparsified Adaptive Cross Approximation (SPACA) is presented for fast iterative solution of the Method of Moments linear system. Like ordinary ACA, it is a completely kernel-independent method, but it is faster and yields a higher compression rate than ordinary ACA, without compromising the accuracy. As an example, the RCS of a perfectly conducting sphere is computed using up to 786,432 basis functions. It is shown that SPACA exhibits close to NlogN complexity for this problem. Mon, 11 Mar 2013 12:16:47 GMT http://hdl.handle.net/2117/18172 2013-03-11T12:16:47Z Heldring, Alexander; Rius Casals, Juan Manuel; Úbeda Farré, Eduard; Tamayo Palau, José María no A new algorithm, the Sparsified Adaptive Cross Approximation (SPACA) is presented for fast iterative solution of the Method of Moments linear system. Like ordinary ACA, it is a completely kernel-independent method, but it is faster and yields a higher compression rate than ordinary ACA, without compromising the accuracy. As an example, the RCS of a perfectly conducting sphere is computed using up to 786,432 basis functions. It is shown that SPACA exhibits close to NlogN complexity for this problem. http://hdl.handle.net/2117/18036 Title: Validation of a sea surface model for simulations of dynamic maritime SAR images Authors: Yam Ontiveros, Luis Eduardo; Mallorquí Franquet, Jordi Joan; Rius Casals, Juan Manuel Abstract: Controllable maritime scenarios have become a central issue in the research of new applications of SAR imaging to vessel monitoring systems. Numerical tools such as GRECOSAR, a SAR simulator of complex targets, are able to provide suitable test-beds as long as the model of the targets (vessels) and the sea surface resemble to what is expected in real maritime scenes. This paper presents the validation of SAR simulated images from GRECOSAR while using a dynamic and multi-harmonic elevation model of the sea surface. The simulations are carried out for generic C- and X-band SAR sensors. The results of the co-polar cha nnels are compared with K,lognormal, Weibull and Rayleigh distributions, which are commonly used to describe statistics of real SAR images of the sea surface. The results show that the clutter has statistics clos er to the K and Weibull distributions, suggesting that the elevation model presented can provide a more realistic approach in simulating SAR images of maritime scenarios Fri, 01 Mar 2013 13:46:52 GMT http://hdl.handle.net/2117/18036 2013-03-01T13:46:52Z Yam Ontiveros, Luis Eduardo; Mallorquí Franquet, Jordi Joan; Rius Casals, Juan Manuel no Controllable maritime scenarios have become a central issue in the research of new applications of SAR imaging to vessel monitoring systems. Numerical tools such as GRECOSAR, a SAR simulator of complex targets, are able to provide suitable test-beds as long as the model of the targets (vessels) and the sea surface resemble to what is expected in real maritime scenes. This paper presents the validation of SAR simulated images from GRECOSAR while using a dynamic and multi-harmonic elevation model of the sea surface. The simulations are carried out for generic C- and X-band SAR sensors. The results of the co-polar cha nnels are compared with K,lognormal, Weibull and Rayleigh distributions, which are commonly used to describe statistics of real SAR images of the sea surface. The results show that the clutter has statistics clos er to the K and Weibull distributions, suggesting that the elevation model presented can provide a more realistic approach in simulating SAR images of maritime scenarios http://hdl.handle.net/2117/17647 Title: Study on aerosol properties over Madrid (Spain) by multiple instrumentation during SPALI10 lidar campaign Authors: Molero, Francisco; Sicard, Michaël; Navas Guzmán, Francisco; Preissler, J.; Amodeo, Aldo; Freudenthaler, Volker; Fernández, J.A.; Tomás Martínez, Sergio; Granados, M.; Wagner, F.; Giunta, Aldo; Mattis, I.; Pujadas, Manuel; Comerón Tejero, Adolfo; Alados Arboledas, Lucas; Guerrero Rascado, Juan Luis; D'Amico, Giuseppe; Lange, Diego; Kumar, Dhiraj; Pappalardo, Gelsomina; Giner Nos, Joaquín José; Muñoz Porcar, Constantino; Rocadenbosch Burillo, Francisco Abstract: Cuatro sistemas lidar Raman multifrecuencia (Madrid, Granada, Barcelona y Evora), tomaron medidas simultáneamente a un sistema de referencia (Potenza) para verificar su funcionamiento durante la campaña de intercomparación: SPALI10, (SPAin Lidar Intercomparison 2010) que tuvo lugar en Madrid entre el 18 de Octubre y el 5 de Noviembre de 2010. Estos sistemas lidar Raman multifrecuencia proporcionan propiedades ópticas de los aerosoles con resolución vertical. Los perfiles suministrados por los sistemas lidar se compararon con información complementaria proporcionada por otra instrumentación, tal como la distribución de tamaños de los aerosoles medida de manera continua a nivel de superficie o la caracterización de la columna de aerosoles Tue, 12 Feb 2013 09:56:33 GMT http://hdl.handle.net/2117/17647 2013-02-12T09:56:33Z Molero, Francisco; Sicard, Michaël; Navas Guzmán, Francisco; Preissler, J.; Amodeo, Aldo; Freudenthaler, Volker; Fernández, J.A.; Tomás Martínez, Sergio; Granados, M.; Wagner, F.; Giunta, Aldo; Mattis, I.; Pujadas, Manuel; Comerón Tejero, Adolfo; Alados Arboledas, Lucas; Guerrero Rascado, Juan Luis; D'Amico, Giuseppe; Lange, Diego; Kumar, Dhiraj; Pappalardo, Gelsomina; Giner Nos, Joaquín José; Muñoz Porcar, Constantino; Rocadenbosch Burillo, Francisco no Aerosols, Lidar, Size Distributions Cuatro sistemas lidar Raman multifrecuencia (Madrid, Granada, Barcelona y Evora), tomaron medidas simultáneamente a un sistema de referencia (Potenza) para verificar su funcionamiento durante la campaña de intercomparación: SPALI10, (SPAin Lidar Intercomparison 2010) que tuvo lugar en Madrid entre el 18 de Octubre y el 5 de Noviembre de 2010. Estos sistemas lidar Raman multifrecuencia proporcionan propiedades ópticas de los aerosoles con resolución vertical. Los perfiles suministrados por los sistemas lidar se compararon con información complementaria proporcionada por otra instrumentación, tal como la distribución de tamaños de los aerosoles medida de manera continua a nivel de superficie o la caracterización de la columna de aerosoles http://hdl.handle.net/2117/17182 Title: Efficient parametric characterization of the dynamic performance of an RFID IC Authors: Capdevila Cascante, Santiago; Jofre Roca, Lluís; Romeu Robert, Jordi; Bolomey, J.Ch Abstract: In this letter, a measurement technique for a complete parametric characterization of the input impedance of an RFID IC is presented. The use of an SPDT switch to modulate the signal from the network analyzer provides the capability to measure the RFID IC activation level and its input impedance simultaneously. This data can then be used to fully predict the dynamic response and performance of an RFID tag. Thu, 20 Dec 2012 15:50:02 GMT http://hdl.handle.net/2117/17182 2012-12-20T15:50:02Z Capdevila Cascante, Santiago; Jofre Roca, Lluís; Romeu Robert, Jordi; Bolomey, J.Ch no Characterization, Input impedance, Modulated scattering technique (MST), Radio frequency identification (RFID), Single pole double throw (SPDT) In this letter, a measurement technique for a complete parametric characterization of the input impedance of an RFID IC is presented. The use of an SPDT switch to modulate the signal from the network analyzer provides the capability to measure the RFID IC activation level and its input impedance simultaneously. This data can then be used to fully predict the dynamic response and performance of an RFID tag. http://hdl.handle.net/2117/17174 Title: Parasitic layer-based reconfigurable antenna design by multi-objective optimization Authors: Yuan, Xiaoyan; Li, Zhouyuan; Rodrigo López, Daniel; Mopidevi, Hema Swaroop; Kaynar, Oguz; Jofre Roca, Lluís; Cetiner, Bedri Artug Abstract: A parasitic layer-based multifunctional reconfigurable antenna (MRA) design based on multi-objective genetic algorithm optimization used in conjunction with full-wave EM analysis is presented. TheMRA is capable of steering its beam into three different directions simultaneously with polarization reconfigurability having six different modes of operation. The MRA consists of a driven microstrip-fed patch element and a reconfigurable parasitic layer, and is designed to be compatible with IEEE-802.11 WLAN standards (5–6 GHz range). The parasitic layer is placed on top of the driven patch. The upper surface of the parasitic layer has a grid of 5 5 electrically small rectangular-shaped metallic pixels, i.e., reconfigurable parasitic pixel surface. The EM energy from the driven patch element couples to the reconfigurable parasitic pixel surface by mutual coupling. The adjacent pixels are connected/disconnected by means of switching, thereby changing the geometry of pixel surface, which in turn changes the current distribution over the parasitic layer, results in the desired mode of operation in beam direction and polarization. A prototype of the designed MRA has been fabricated on quartz substrate. The results from simulations and measurements agree well indicating 8 dB gain in all modes of operation. Thu, 20 Dec 2012 13:50:33 GMT http://hdl.handle.net/2117/17174 2012-12-20T13:50:33Z Yuan, Xiaoyan; Li, Zhouyuan; Rodrigo López, Daniel; Mopidevi, Hema Swaroop; Kaynar, Oguz; Jofre Roca, Lluís; Cetiner, Bedri Artug no Beam steering, full-wave analysis, multi-objective genetic algorithm, reconfigurable antenna A parasitic layer-based multifunctional reconfigurable antenna (MRA) design based on multi-objective genetic algorithm optimization used in conjunction with full-wave EM analysis is presented. TheMRA is capable of steering its beam into three different directions simultaneously with polarization reconfigurability having six different modes of operation. The MRA consists of a driven microstrip-fed patch element and a reconfigurable parasitic layer, and is designed to be compatible with IEEE-802.11 WLAN standards (5–6 GHz range). The parasitic layer is placed on top of the driven patch. The upper surface of the parasitic layer has a grid of 5 5 electrically small rectangular-shaped metallic pixels, i.e., reconfigurable parasitic pixel surface. The EM energy from the driven patch element couples to the reconfigurable parasitic pixel surface by mutual coupling. The adjacent pixels are connected/disconnected by means of switching, thereby changing the geometry of pixel surface, which in turn changes the current distribution over the parasitic layer, results in the desired mode of operation in beam direction and polarization. A prototype of the designed MRA has been fabricated on quartz substrate. The results from simulations and measurements agree well indicating 8 dB gain in all modes of operation.