Girbau Sala, David
Total activity: 16
Department
Department of Signal Theory and Communications
E-mail
david.girbauestudiant.upc.edu
Contact details
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Scientific and technological production
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1 to 16 of 16 results
  • Design of Isofrequency Reconfigurable Repeaters

     Diaz Tapia, Edgar
    Defense's date: 2013-10-28
    Department of Signal Theory and Communications, Universitat Politècnica de Catalunya
    Theses

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  • Multimodal Microwave Filters

     Contreras Lizarraga, Adrian Arturo
    Defense's date: 2013-11-29
    Department of Signal Theory and Communications, Universitat Politècnica de Catalunya
    Theses

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  • RFID Multiantenna Systems for Wireless Communications and Sensing  Open access

     Capdevila Cascante, Santiago
    Defense's date: 2013-02-15
    Department of Signal Theory and Communications, Universitat Politècnica de Catalunya
    Theses

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    Many scientific, industrial and medical applications require the measurement of different physical parameters in order to collect information about the spatially distributed status of some process. Very often this information needs to be collected remotely, either due to the spatial dispersion of the measurement points or due to their inaccessibility. A wireless embedded self-powered sensor may be a convenient solution to be placed at these inaccessible locations. This thesis is devoted to study the analytical relation governing the electromagnetic coupling between a reader and a embeddable self-powered sensor, based on radio frequency identification (RFID) technology, which is capable of wirelessly retrieving the status of physical parameters at a remote and inaccessible location. The physical parameter to be sensed may be the electromagnetic (EM) field existing at that location (primary measurement) or the indirect measurement of other parameters such as the temperature, humidity, etc. (secondary measurement). Given the simplicity of the RFID solution (highly embeddable properties, scavenging capabilities, penetration and radio coverage characteristics, etc.) the measurement can be done at a single location, or it can be extended to a set of measuring locations (an array or grid of sensors). The analytical relation is based on a reciprocity formulation studying the modulation of the scattered field by the embedded sensor in relation with the incident field, and allows to define a set of quality parameters of interest for the optimum design of the sensors. Particular attention is given to the scavenging circuitry as well as to the antenna design relevant to the sensing objective. In RFID tags, the existence of an RF harvesting section is an improvement with respect to conventional scattering field probes since it removes the need of DC biasing lines or optical fibers to modulate the sensor. However, this harvesting section introduces non-linearities in the response of the sensor, which requires a proper correction to use them as EM-field probes, although the characterization of the non-linearities of the RFID tag cannot be directly done using a conventional vector network analyzer (VNA), due to the requirements of an RFID protocol excitation. Due to this, this thesis proposes an alternative measurement approach that allows to characterize the different scattering states used for the modulation, in particular its non-linear behavior. In addittion, and taking this characterization as the starting point, this thesis proposes a new measurement setup for EM-field measurements based on the use of multiple tones to enlarge the available dynamic range, which is experimentally demonstrated in the measurement of a radiation pattern, as well as in imaging applications. The RFID-based sensor response is electromagnetically sensitive to the dielectric properties of its close environment. However, the governing formulation for the response of the probe mixes together a set of different contributions, the path-loss, the antenna impedance, the loads impedance, etc. As a consequence, it is not possible to isolate each contribution from the others using the information available with a conventional RFID sensor. This thesis mathematically proposes and experimentally develops a modification of the modulation scheme to introduce a new set of multi-load scattering states that increases the information available in the response and properly isolate each term. Moreover, this thesis goes a step forward and introduces a new scattering state of the probe sensitive to temperature variations that do not depend on the environment characteristics. This new configuration enables robust environmental sensing in addition to EM-field measurements, and sensing variations of the dielectric properties of the environment.

  • RF-MEMS uniplanar 180º Phase Switch based on switching between two out-of-phase paths

     Llamas Morote, Marco Antonio; Ribó, Miquel; Girbau Sala, David; Pradell Cara, Lluis; Lázaro Guillén, Antonio; Giacomozzi, Flavio; Margesin, Benno
    International Conference on RF MEMS and RF Microsystems
    Presentation's date: 2010-06-28
    Presentation of work at congresses

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    A phase switch based on switching between two twoport passive networks with a phase difference of 180º is reported. Two RF MEMS single-pole-double-throw structures are used to select the phase path. The fabrication is made on both highresistivity silicon and quartz substrates using the eight-mask FBK-irst surface micromachining process. The measured phase shift is 180º±5º in the frequency range 14−20 GHz on quartz wafers and in the range 8−20 Ghz on silicon wafers.

  • Tunable dual-band filters based on capacitive-loaded stepped-impedance resonators

     Pradell Cara, Lluis; Girbau Sala, David; Pérez, Albert; Lázaro Guillén, Antonio; Martínez, Esther; Villarino, Ramon
    International journal of microwave and wireless technologies
    Date of publication: 2010
    Journal article

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  • A method for characterization of intermodulation distortion produced in mems switches

     Girbau Sala, David; Pradell Cara, Lluis; Lazaro, A; Peyrou, D; Pons, P; Calmon, P
    Microwave and optical technology letters
    Date of publication: 2009-02
    Journal article

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  • MEMS switches and capacitors for microwave communication systems

     Girbau Sala, David
    Defense's date: 2006-07-14
    Department of Signal Theory and Communications, Universitat Politècnica de Catalunya
    Theses

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  • Documentación técnica del sistema MVDS

     Lazaro Guillen, Antoni; Girbau Sala, David; de Paco Sánchez, Pedro Antonio
    Date: 2001-04
    Report

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  • Filtre de llaç analògic

     Girbau Sala, David; Lazaro Guillen, Antoni; Pradell Cara, Lluis
    Date: 2001-04
    Report

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  • PLO BX

     Girbau Sala, David; Lazaro Guillen, Antoni; Pradell Cara, Lluis
    Date: 2001-09
    Report

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  • Oscil.lador referència i alarma de 'lock' pel convertidor Miteq

     Girbau Sala, David; Lazaro Guillen, Antoni; Pradell Cara, Lluis
    Date: 2001-05
    Report

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  • PLO amb detector de fase mostrejat

     Girbau Sala, David; Lazaro Guillen, Antoni; Pradell Cara, Lluis
    Date: 2001-05
    Report

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  • Upconverter per eqtapa Fi de LMDS

     Lazaro Guillen, Antoni; Girbau Sala, David; Pradell Cara, Lluis
    Date: 2001-04
    Report

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  • Modulador I/Q

     Lazaro Guillen, Antoni; Girbau Sala, David; Pradell Cara, Lluis
    Date: 2001-05
    Report

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  • Upconverter i downconver

     Lazaro Guillen, Antoni; Girbau Sala, David; Pradell Cara, Lluis
    Date: 2001-05
    Report

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