La adaptacion del plan nacional de evaluacion de la calidad de las universidades al contexto de una universidad con estructura matricial de centros y departamentos: el caso de la universidad politecnica de cataluña

Peer ReviewedPostprint (published version

Truncation errors in cylindrical near to far field transform. A plane wave synthesis approach

Cylindrical Near to far field antenna transformation is expressed as a plane wave synthesis problem where a plane wave is produced by a cylindrical current distribution that encloses the Antenna Under Test (AUT). The current distribution that produces the plane wave is directly derived from the near to far field transformation algorithm.Peer ReviewedPostprint (published version

Science and technology vocations in Catalonia

Little vocation: Lack of appeal, difficulty to grasp the subject in secondary school and unattractive salary perspectives and professional career

Les vocacions científiques i tècniques a Catalunya

Poca vocació: manca d’atractiu i perspectives poc atractives de les retribucions salarials i les carreres professional

Clined: collaborative learning for innovative engineering design

El Projecte CLINED s’emmarca en el procés de desenvolupament del mòdul d’aprenentatge interactiu “Array Antennas” en el context de l’assignatura d’Antenes de l’Escola Tècnica Superior Enginyeria de Telecomunicació de Barcelona (ETSETB). Aquest bloc del temari suposa un crèdit ECTS sent els principals objectius en aquest procés d’adaptació: fomentar el treball progressiu de l’estudiant, el seu esperit innovador i creatiu alhora que adquireixi major capacitat de relació entre els models conceptuals explicats i les estructures reals. Per assolir aquestes fites s’ha dut a terme una experiència pilot d’aprenentatge col·laboratiu de forma que es cobreixen els punts esmentats i s’aconsegueixi que l’estudiant tingui un rol més actiu en el seu propi aprenentatge fent que aquest li resulti més atractiu. A més d’aquest pilot realitzat durant el cursos 2004/2005, 2005/2006 y el quatrimestre de tardor 2006, s’han introduït presentacions en power point del tema d’arrays i s’ha posat a disposició de tots els alumnes video-based lectures, i una eina de simulació que els permet fer tan síntesi com anàlisi per l’estudi del comportament d’antenes i les seves agrupacions

Comparative efficiency and power assessment of optical photoconductive material-based terahertz sources for wireless communication systems

Electronic version of an article published as [Journal of Circuits, Systems and Computers, vol. 28, num. 1, 2018] [https://doi.org/10.1142/S0218126619500051] © [copyright World Scientific Publishing Company] [https://www.worldscientific.com/worldscinet/jcsc]Terahertz band has recently attracted the attention of the communication society due to its huge bandwidth and very high-speed wireless communications capability. It has been utilized in a variety of disciplines including physics, biology and astronomy for years; and the main concerns have always been obtaining highly efficient and high-power terahertz sources. Today, these problems are still the most important issues in establishing an operable wireless terahertz communication link. In this paper, recent studies in the field of terahertz source design are investigated based on the terahertz output power and efficiency. Solid-state sources and optical sources were comparatively reviewed with optical photoconductive material (OPM)-based methods which are combined with the terahertz antennas in the design phase generally. For wireless communication, the most suitable frequencies are between 0.3THz and 1THz due to the attenuation profile of the atmosphere. For this reason, based on the recently published studies, it has been observed that OPM and resonant tunneling diode-based sources are the most promising terahertz sources in terms of efficiency and power. Key issues and the main problems of terahertz photoconductive antennas which are the base of OPM method were also discussed in this paper.Peer ReviewedPostprint (author's final draft

Bidimensional scattering of tm and te polarized waves by dielectric

In the study of electromagnetic radiation effects over dielectric bodies, effective numerical methods are needed. At present, there is a lack of tools for measuring this effects and due to the huge growth of microwave devices, like cellular radio telephones working close to the human body, it is necessary to develop accurate numerical methods for evaluating those effects. One of the most efficient and extensively used method is the FFT-CGM (Fast-Fourier-Transform Conjugate Gradient Method). In this paper, algorithms for solving the two-dimensional scattering of transversal magnetic (TM) and transversal electric (TE) polarized waves by a lossy dielectric and metallic objects are presented. At the same time, the SAR (Specific Absorption Rate) of tissues and the modified radiation diagrams when the body is present are obtained from the diffracted fields.Peer ReviewedPostprint (published version

Caracterización electromagnética de materiales RAM mediante medidas en espacio libre

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.Peer ReviewedPostprint (published version

Miniature multi-element antenna for wireless communications

We present a novel broad-band miniature antenna and employ it in a multi-element geometry with diversity capabilities for wireless communications. This antenna (diameter < 0.2 λ and thickness < 0.06 λ) consists of two stacked circular patches that create two cylindrical slots resonating at two slightly different frequencies, fed by a strategically positioned coaxial probe. An extensive parametric study and results for a prototype working at 5.2 GHz are presented. A multi-element geometry with two or four of such elements follows. Microelectromechanical system (MEMS)-based switches located within its geometry can not only change the working frequency of the design, but also activate a particular radiation beam depending on their specific location (resonant slot-aperture or feed line). Simulation results of a four-element antenna with dimensions 0.8 λ × 0.8 λ × 0.06 λ and a frequency band operation from 5 to 6 GHz are presented and compared to an experimental prototype. Circuit and radiation characteristics are discussed in terms of reconfigurability and diversity capabilities.Peer Reviewe