Diseño de un dique flotante de 7.000 toneladas de fuerza ascensional : estudio de la estructura y de los servicios.

Los objetivos principales de este trabajo son, por una parte, diseñar la estructura de un dique flotante, y por otro lado, estudiar y analizar los sistemas y servicios que incorpora el mismo que permiten la realización de todas estas actividades. Para llevar a cabo el diseño estructural, se efectuarán los distintos avances de la espiral de diseño hasta alcanzar la estructura óptima. El cálculo de los diseños estructurales se realizará mediante un software basado en el método de los elementos finitos, RamSeries 12.0.0

NFC Sensors Based on Energy Harvesting for IoT Applications

The availability of low-cost near-field communication (NFC) devices, the incorporation of NFC readers into most current mobile phones, and the inclusion of energy-harvesting (EH) capabilities in NFC chips make NFC a key technology for the development of green Internet of Things (IoT) applications. In this chapter, an overview of recent advances in the field of battery-less NFC sensors at 13.56 MHz is provided, and a comparison to other short-range RFID technologies is given. After reviewing power transfer in NFC, recommendations for the practical design of NFC-based sensor tags and NFC readers are made. A list of commercial NFC integrated circuits with energy-harvesting capabilities is also provided. A survey of recent battery-less NFC sensors developed by the group including soil moisture, water content, pH, color, and implanted NFC sensors is done

Implementació d'una estratègia de control de processos en una unitat de fabricació d'envasos plàstics

Els departaments de producció en la industria de productes de gran consum necessiten reduir els seus costos per continuar sent competitius en el mercat. Les pèrdues associades a la qualitat del producte, així com les mermes que es generen en els processos de producció d’envasos plàstics, és una de les principals oportunitats per aconseguir aquesta millora de la competitivitat. L’objectiu d’aquest projecte és implementar una estratègia de control de processos que ens permeti reduir les fonts de variabilitat en un procés d’extrusió i bufat d’envasos plàstics, per tal de millorar la qualitat dels productes i l’eficiència del procés a fi de reduir els costos de producció. Els passos en els que està estructurat aquest projecte són els següents: Ø Una anàlisi de la situació actual de l’unitat de fabricació d’envasos plàstics que s’estudiarà, en el qual es descriu la tecnologia, els materials i els principals punts del procés de transformació per entendre el marc d’aplicació del projecte. Ø Una explicació de la metodologia emprada per establir una estratègia de control de processos pas a pas i la seva implementació a la unitat de fabricació amb l’anàlisi dels principals problemes que existeixen actualment en aquesta unitat. Ø Una anàlisi dels principals problemes que existeixen a la unitat de bufat, i l’elaboració d’un pla d’acció que permeti disminuir les pèrdues de qualitat, reduir les mermes i millorar l’eficiència del procés de fabricació. En cada cas es fa una avaluació de les implicacions econòmiques del pla de millora així com dels beneficis obtinguts. Es conclou que amb la implementació d’aquesta estratègia de control de processos i la posada en marxa de les millores identificades durant aquest projecte, s’aconsegueix una millora substancial dels resultats de qualitat, la reducció de mermes del procés productiu i una millora de l’eficiència i la productivitat del departament. A més, es crea una atmosfera de millora continua per assegurar la sostenibilitat dels resultats obtinguts

Distortion produced by RF MEMS varactors on digital communication signals

This paper presents a study of the nonlinear effects introduced by MEMS varactors when excited with digitally modulated RF signals (QPSK and 16 QAM). The study is based on simulating a nonlinear model of the MEMS device using harmonic-balance and envelope solvers, and on experimental measurements of the wave reflected by the on-wafer MEMS device. It is shown that the adjacent-channel power ratio (ACPR) and error-vector magnitude (EVM) of the digital signal suffer a degradation due to the device nonlinear distortion.Peer Reviewe

Characterization of dynamics and power handling of RF MEMS using vector measurement techniques

This paper proposes a new method to measure dynamics and power handling of RF microelectromechanical systems (MEMS) devices based on a mobile membrane. The method uses in-phase/quadrature demodulation of an RF signal proportional to the reflection coefficient of the measured device, which contains information of its mechanical properties, such as actuation and release times and instantaneous position of the mobile membrane. Both one-port (capacitors) and two-port devices (switches and extended tuning-range capacitors) can be measured. Its main advantage is the capability of obtaining information from both magnitude and phase variations of the device reflection coefficient to characterize its dynamics and power handling. It is shown that detecting phase is advantageous in high quality factor capacitors, where the magnitude of the reflection coefficient is nearly constant for any position of the mobile membrane. Open-short-load calibration of the system is provided in order to obtain absolute measurements, which are necessary for power-handling characterization. The performances of the proposed method are demonstrated by comparison to systems based on detection of the magnitude of the reflection coefficient. A MEMS capacitor is characterized in terms of dynamics-actuation and release times, and mechanical resonance frequency and in terms of power handling-membrane instantaneous position and phase and tuning range variation.Peer Reviewe

A Passive Harmonic Tag for Humidity Sensing

This paper describes a passive harmonic tag for radio frequency identification (RFID) and wireless sensor applications. The tag uses a dual polarized UHF patch antenna as an input antenna. One of the outputs is connected to a frequency doubler, which consists of a Schottky diode with its output connected to a patch tuned at twice the input frequency. The other output of the input antenna feeds a DC power harvested converter that drives an oscillator which modulates its output signal by controlling the bias point of the Schottky diode. The antenna’s output is also used as a humidity sensor. To achieve this, the antenna is loaded with an interdigital capacitor with humidity-dependent capacitance. The antenna is consequently detuned when humidity varies, and therefore the second harmonic power is received. The tag is manufactured using standard fiberglass substrate. The basic theory of harmonic tag operation is described and compared with the standard backscattering approach. Experimental results with a proof of concept using commercial components are presented

Nonlinear actuation model for lateral electrostatically-actuated DC-contact RF MEMS series switches.

In this work, a nonlinear model to predict actuation characteristics in lateral electrostatically-actuated DC-contact MEMS switches is proposed. In this case a parallel-plate approximation cannot be applied. The model is based on the equilibrium equation for an elastic beam. It is demonstrated that the contribution of fringing fields is essential. The model relies on finite-difference discretization of the structures, applying boundary conditions and is solved with a Gauss- Seidel relaxation iteration scheme. Its usefulness is demonstrated in a series MEMS switch with lateral interdigital electrostatic actuation.Peer Reviewe

Electrothermally actuated RF MEMS switches suspended on a low-resistivity substrate

This paper presents an electrothermally actuated lateral resistive-contact switch for application to low-gigahertz-band communication systems. It was manufactured on a standard low-resistivity substrate, and its RF performance was improved by suspending the structures 25 μm from the substrate, which is a strategy for future integration with active devices in the system-on-chip concept. Measured insertion losses are−0.26 dB at 1 GHz and −0.65 dB at 6 GHz, return losses are −29 dB at 1 GHz and −25 dB at 6 GHz, and isolations are −52 dB at 1 GHz and −26 dB at 6 GHz. The device is driven by a metal electrothermal actuator, which achieves large displacements and contact forces at much lower temperatures than traditional polysilicon electrothermal actuators. The RF power handling characteristics are also addressed and measured.Peer Reviewe

Study of intermodulation in RF MEMS variable capacitors

This paper provides a rigorous study of the causes and physical origins of intermodulation distortion (IMD) in RF microelectromechanical systems (MEMS) capacitors, its analytical dependence on the MEMS device design parameters, and its effects in RF systems. It is shown that not only third-order products exist, but also fifth order and higher. The high-order terms are mainly originated by the nonlinear membrane displacement versus applied voltage and, in the case considered in this study, with an additional contribution from the nonlinear dependence of the reflection coefficient phase on the displacement. It is also shown that the displacement nonlinear behavior also contributes to the total mean position of the membrane. In order to study these effects in depth, an analytical frequency-dependent IMD model for RF MEMS based on a mobile membrane is proposed and particularized to the case of a MEMS varactor-a device for which IMD can be significant. The model is validated, up to the fifth order, theoretically (using harmonic balance) and empirically (the IMD of a MEMS varactor is measured). To this end, a two-tone IMD reflection measurement system for MEMS is proposed.Peer Reviewe

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

This paper proposes the design of tunable dual-band filters for multi-band multi-standard systems. The main objective is to provide frequency tunability in the second band while maintaining the first band fixed. To this end, the capacitive-loaded stepped-impedance resonator is used. The work is divided into two main parts. In the first part, a deep analysis of the capacitive-loaded stepped-impedance resonator structure is done, which provides analytical closed-form design equations which eases their design in front of the several approaches available in the literature up to now. The analysis is also particularized for the case of the capacitive-loaded uniform resonator. In the second part, resonators are integrated in two dual-band tunable filters.Postprint (published version