Ponències/Comunicacions de congressos
http://hdl.handle.net/2117/659
Tue, 07 Jul 2020 07:25:19 GMT
20200707T07:25:19Z

A 3D printed lens antenna for 5G applications
http://hdl.handle.net/2117/187869
A 3D printed lens antenna for 5G applications
Ballesteros, Christian; Maestre, Marcos; Santos Blanco, M. Concepción; Romeu Robert, Jordi; Jofre Roca, Lluís
A switchable multiantenna architecture for lensassisted beamsteering in the Kaband region allocated for 5G communications (2430 GHz) is proposed. The radiating elements are bowtie antennas mounted with a 3D printed highpermittivity dielectric lens (e r = 10). A 5element array is simulated showing switchable 30° beam steering over a 120° sector with 19 dB maximum gain. Single antenna measurements of a scaled prototype with a Polylactic Acid (PLA) lens (e r = 2.7) show gains around 11 dB, in agreement with projected performances.
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Mon, 18 May 2020 10:22:21 GMT
http://hdl.handle.net/2117/187869
20200518T10:22:21Z
Ballesteros, Christian
Maestre, Marcos
Santos Blanco, M. Concepción
Romeu Robert, Jordi
Jofre Roca, Lluís
A switchable multiantenna architecture for lensassisted beamsteering in the Kaband region allocated for 5G communications (2430 GHz) is proposed. The radiating elements are bowtie antennas mounted with a 3D printed highpermittivity dielectric lens (e r = 10). A 5element array is simulated showing switchable 30° beam steering over a 120° sector with 19 dB maximum gain. Single antenna measurements of a scaled prototype with a Polylactic Acid (PLA) lens (e r = 2.7) show gains around 11 dB, in agreement with projected performances.

Study of interconnecting switch currents in reconfigurable parasitic layer antennas
http://hdl.handle.net/2117/185707
Study of interconnecting switch currents in reconfigurable parasitic layer antennas
Ramirez, German; Araque, Javier; Ballesteros Sánchez, Christian; Blanch Boris, Sebastián; Romeu Robert, Jordi; Cetiner, Bedri Artug; Jofre Roca, Lluís
This work presents an approach for calculating the currents across the switches of a reconfigurable parasitic layer intended to add beamsteering capabilities to a reference antenna. The method of analysis is based on the port loading technique in which only one FullWave Electromagnetic (FWEM) simulation is required to evaluate the behavior of the reference antenna and its interaction with the reconfigurable layer across all its states. Results show that the currents on the switches are at least one order of magnitude lower than the currents on the feed port of the driven radiator, proving the effectiveness of the reconfigurable parasitic layer approach in implementing Reconfigurable Antenna (RA).
Wed, 29 Apr 2020 09:23:00 GMT
http://hdl.handle.net/2117/185707
20200429T09:23:00Z
Ramirez, German
Araque, Javier
Ballesteros Sánchez, Christian
Blanch Boris, Sebastián
Romeu Robert, Jordi
Cetiner, Bedri Artug
Jofre Roca, Lluís
This work presents an approach for calculating the currents across the switches of a reconfigurable parasitic layer intended to add beamsteering capabilities to a reference antenna. The method of analysis is based on the port loading technique in which only one FullWave Electromagnetic (FWEM) simulation is required to evaluate the behavior of the reference antenna and its interaction with the reconfigurable layer across all its states. Results show that the currents on the switches are at least one order of magnitude lower than the currents on the feed port of the driven radiator, proving the effectiveness of the reconfigurable parasitic layer approach in implementing Reconfigurable Antenna (RA).

Efficient and accurate electromagnetic scattering analysis of perfectly conducting thick plates
http://hdl.handle.net/2117/185625
Efficient and accurate electromagnetic scattering analysis of perfectly conducting thick plates
Úbeda Farré, Eduard; Sekulic, Ivan; Rius Casals, Juan Manuel
The scattering analysis with the ElectricField Integral Equation by the Method of Moments of perfectly conducting plates is normally carried out through the thinplate approximation, which models the closed surface as an open surface and discards the influence of the plate rim. The resulting accuracy is accepted in many practical applications as long as the thickness of the plate is small enough. However, in the scattering analysis of plates with grazing incidences, the thinplate approximation gives rise to severe inaccuracies. In this paper, we present a new numerical approach, which we name thickplate formulation, for the accurate computation of the current and the RCS for a plate with nonzero thickness. Our scheme provides similar accuracy as the solution obtained with the full modelling of the plate and with less computational time.
Wed, 29 Apr 2020 05:37:54 GMT
http://hdl.handle.net/2117/185625
20200429T05:37:54Z
Úbeda Farré, Eduard
Sekulic, Ivan
Rius Casals, Juan Manuel
The scattering analysis with the ElectricField Integral Equation by the Method of Moments of perfectly conducting plates is normally carried out through the thinplate approximation, which models the closed surface as an open surface and discards the influence of the plate rim. The resulting accuracy is accepted in many practical applications as long as the thickness of the plate is small enough. However, in the scattering analysis of plates with grazing incidences, the thinplate approximation gives rise to severe inaccuracies. In this paper, we present a new numerical approach, which we name thickplate formulation, for the accurate computation of the current and the RCS for a plate with nonzero thickness. Our scheme provides similar accuracy as the solution obtained with the full modelling of the plate and with less computational time.

Geometric algebra formulation of the Calderon Projector
http://hdl.handle.net/2117/184398
Geometric algebra formulation of the Calderon Projector
López Menchón, Héctor; Rius Casals, Juan Manuel; Úbeda Farré, Eduard; Heldring, Alexander
Geometric Algebra provides a mathematical framework that allows to express many equations of physics in a more compact way [1]. It unifies the electric and the magnetic field in a single mathematical object: a multivector. Then, the four Maxwell’s equations can be written as a single one. Here we study how the integral formulation of the electromagnetic field in Geometric Algebra naturally embeds the Calderon Projector when the field is evaluated in a surface.
Thu, 23 Apr 2020 06:31:34 GMT
http://hdl.handle.net/2117/184398
20200423T06:31:34Z
López Menchón, Héctor
Rius Casals, Juan Manuel
Úbeda Farré, Eduard
Heldring, Alexander
Geometric Algebra provides a mathematical framework that allows to express many equations of physics in a more compact way [1]. It unifies the electric and the magnetic field in a single mathematical object: a multivector. Then, the four Maxwell’s equations can be written as a single one. Here we study how the integral formulation of the electromagnetic field in Geometric Algebra naturally embeds the Calderon Projector when the field is evaluated in a surface.

Gridrobust discretization of integral equations in the electromagnetic scattering analysis of homogeneous targets with geometric singularities
http://hdl.handle.net/2117/184397
Gridrobust discretization of integral equations in the electromagnetic scattering analysis of homogeneous targets with geometric singularities
Úbeda Farré, Eduard; Sekulic, Ivan; Rius Casals, Juan Manuel
The conventional methodofmoment schemes of discretization for the scattering analysis of homogeneous targets, perfectly conducting or dielectric, rely on edgebased basis functions. This restricts the modelling of the targets to conformal meshes, with all adjacent facets sharing one single edge. Prior to the electromagnetic analysis, edgebased schemes require the execution of edge search algorithms in order to establish the set of interior edges of the mesh. On the other hand, flaws in the mesh generation may give rise to an incomplete identification of the interior edges and a wrong
modelling of the currents. Recently introduced facetbased schemes of discretization of surface integral equations, with volumetric testing, have exhibited improved accuracy in the analysis of targets with geometric singularities. Since facetbased schemes ignore by definition edges, they are better suited than the edgebased schemes for the robust analysis of slightly defective meshes, e.g. with unconnected vertices or misaligned edges.
Thu, 23 Apr 2020 06:23:45 GMT
http://hdl.handle.net/2117/184397
20200423T06:23:45Z
Úbeda Farré, Eduard
Sekulic, Ivan
Rius Casals, Juan Manuel
The conventional methodofmoment schemes of discretization for the scattering analysis of homogeneous targets, perfectly conducting or dielectric, rely on edgebased basis functions. This restricts the modelling of the targets to conformal meshes, with all adjacent facets sharing one single edge. Prior to the electromagnetic analysis, edgebased schemes require the execution of edge search algorithms in order to establish the set of interior edges of the mesh. On the other hand, flaws in the mesh generation may give rise to an incomplete identification of the interior edges and a wrong
modelling of the currents. Recently introduced facetbased schemes of discretization of surface integral equations, with volumetric testing, have exhibited improved accuracy in the analysis of targets with geometric singularities. Since facetbased schemes ignore by definition edges, they are better suited than the edgebased schemes for the robust analysis of slightly defective meshes, e.g. with unconnected vertices or misaligned edges.

A model for photocurrent generation in photoconductive antennas
http://hdl.handle.net/2117/184392
A model for photocurrent generation in photoconductive antennas
López Menchón, Héctor; Revuelta Martinez, Sergio; Santos Blanco, M. Concepción; Romeu Robert, Jordi; Rius Casals, Juan Manuel
The laserinduced current carrier generation and transport under large biasing voltages in photoconductive materials located in electrode gap region of photoconductive antennas is a complex process involving many different phenomena that interact with each other in intricate ways. Given the large biasing voltages employed, a simple model that assumes that the carriers travel along the biasing field lines allows to retain the basic features of the photocarrier generation process. The model is presented in detail and results for a typical interdigitated electrode are shown to well agree with measures found in the literature.
Thu, 23 Apr 2020 05:34:34 GMT
http://hdl.handle.net/2117/184392
20200423T05:34:34Z
López Menchón, Héctor
Revuelta Martinez, Sergio
Santos Blanco, M. Concepción
Romeu Robert, Jordi
Rius Casals, Juan Manuel
The laserinduced current carrier generation and transport under large biasing voltages in photoconductive materials located in electrode gap region of photoconductive antennas is a complex process involving many different phenomena that interact with each other in intricate ways. Given the large biasing voltages employed, a simple model that assumes that the carriers travel along the biasing field lines allows to retain the basic features of the photocarrier generation process. The model is presented in detail and results for a typical interdigitated electrode are shown to well agree with measures found in the literature.

An architecture analysis for millimeterwave optically steerable antenna array
http://hdl.handle.net/2117/184390
An architecture analysis for millimeterwave optically steerable antenna array
Ballesteros Sánchez, Christian; Maestre, Marcos; Santos Blanco, M. Concepción; Romeu Robert, Jordi; Jofre Roca, Lluís
A lensbased integrated photodiodeantenna array for a Radio over Fiber (RoF) 5G wireless base station at millimeterwave frequencies is proposed and analyzed. The elements of the array are based on slot bowtie antennas which ensure a good matching to the photodiode impedance measurements in a band that extends from 23 to 35 GHz. Simulated farfield patterns show that beam steering in 23.5° steps with a minimum peak gain of 15.8 dB may be achieved by means of an optical switch in a 4element array with 3.8 mm spacing using an Acrylonitrile Butadiene Styrene (ABS) extended hemispherical lens with 25 mm radius.
Thu, 23 Apr 2020 05:23:44 GMT
http://hdl.handle.net/2117/184390
20200423T05:23:44Z
Ballesteros Sánchez, Christian
Maestre, Marcos
Santos Blanco, M. Concepción
Romeu Robert, Jordi
Jofre Roca, Lluís
A lensbased integrated photodiodeantenna array for a Radio over Fiber (RoF) 5G wireless base station at millimeterwave frequencies is proposed and analyzed. The elements of the array are based on slot bowtie antennas which ensure a good matching to the photodiode impedance measurements in a band that extends from 23 to 35 GHz. Simulated farfield patterns show that beam steering in 23.5° steps with a minimum peak gain of 15.8 dB may be achieved by means of an optical switch in a 4element array with 3.8 mm spacing using an Acrylonitrile Butadiene Styrene (ABS) extended hemispherical lens with 25 mm radius.

Electromagnetic monitoring of biological microorganisms
http://hdl.handle.net/2117/184389
Electromagnetic monitoring of biological microorganisms
Zarrinkhat, Faezeh; Garrido, Alejandra; Jofre Roca, Lluís; Romeu Robert, Jordi; Rius Casals, Juan Manuel
The investigation of the electromagnetic properties of biological cells in the microwave frequencies may enable wireless monitoring of functional activity of microorganisms. Both theoretical and experimental methodologies are applied to obtain the electromagnetic characterization of the E. Coli cells as a simple microorganism. The simulation and experimental results corresponding to the transmission coefficient and sensitivity of a coaxial setup for different concentration of E. Coli cells are measured up to 3 GHz. Afterwards, the E. Coli is used as the basis to address the electromagnetic changes, in terms of extension and contrast, involved into the creation of a functional activity (action potential) of a neuronal cell.
Thu, 23 Apr 2020 05:12:59 GMT
http://hdl.handle.net/2117/184389
20200423T05:12:59Z
Zarrinkhat, Faezeh
Garrido, Alejandra
Jofre Roca, Lluís
Romeu Robert, Jordi
Rius Casals, Juan Manuel
The investigation of the electromagnetic properties of biological cells in the microwave frequencies may enable wireless monitoring of functional activity of microorganisms. Both theoretical and experimental methodologies are applied to obtain the electromagnetic characterization of the E. Coli cells as a simple microorganism. The simulation and experimental results corresponding to the transmission coefficient and sensitivity of a coaxial setup for different concentration of E. Coli cells are measured up to 3 GHz. Afterwards, the E. Coli is used as the basis to address the electromagnetic changes, in terms of extension and contrast, involved into the creation of a functional activity (action potential) of a neuronal cell.

Imaging system for automotive radome characterization
http://hdl.handle.net/2117/177224
Imaging system for automotive radome characterization
Buitrago Ventura, Santiago; Blanch Boris, Sebastián; Romeu Robert, Jordi
In this paper, a setup to obtain an image of the attenuation and the reflectivity of an automotive radome in the 77 GHz band is presented.The characterization of the reflectivity is becoming an important issue to be considered in an automotive radome design because the important effects it can produce in the radar sensor performance such as a false detection of a target or even a blindness of the radar sensor. In addition, the characterization of the attenuation is also important because the reduction in safety due to a possible nondetection of a target.For that reason, a setup to obtain an image of the attenuation and the reflectivity of a radome at the same time is presented. This system can be used to test prototypes in the design process or in the verification of manufactured samples.
Fri, 07 Feb 2020 18:39:32 GMT
http://hdl.handle.net/2117/177224
20200207T18:39:32Z
Buitrago Ventura, Santiago
Blanch Boris, Sebastián
Romeu Robert, Jordi
In this paper, a setup to obtain an image of the attenuation and the reflectivity of an automotive radome in the 77 GHz band is presented.The characterization of the reflectivity is becoming an important issue to be considered in an automotive radome design because the important effects it can produce in the radar sensor performance such as a false detection of a target or even a blindness of the radar sensor. In addition, the characterization of the attenuation is also important because the reduction in safety due to a possible nondetection of a target.For that reason, a setup to obtain an image of the attenuation and the reflectivity of a radome at the same time is presented. This system can be used to test prototypes in the design process or in the verification of manufactured samples.

Variable capacitive antenna loading for embedded RFID sensors
http://hdl.handle.net/2117/176864
Variable capacitive antenna loading for embedded RFID sensors
Gonzalez, Giselle; Jofre Roca, Lluís; Romeu Robert, Jordi; Cairó Molins, Josep Ignasi
In this paper, a selfadaptive folded dipole antenna to work embedded in media with changing physical and chemical properties for RFID applications is proposed. Selfadaptability is provided by taking advantage of the dualmode behaviour of the folded dipole antenna where variable capacitance diodes are strategically placed to compensate for the change produced in the electromagnetic properties of the embedding medium. The presented antenna has been optimized at 868MHz.
Wed, 05 Feb 2020 14:48:52 GMT
http://hdl.handle.net/2117/176864
20200205T14:48:52Z
Gonzalez, Giselle
Jofre Roca, Lluís
Romeu Robert, Jordi
Cairó Molins, Josep Ignasi
In this paper, a selfadaptive folded dipole antenna to work embedded in media with changing physical and chemical properties for RFID applications is proposed. Selfadaptability is provided by taking advantage of the dualmode behaviour of the folded dipole antenna where variable capacitance diodes are strategically placed to compensate for the change produced in the electromagnetic properties of the embedding medium. The presented antenna has been optimized at 868MHz.