Caracterización de materiales para sensores de radiofrecuencia

El conocimiento de la permitividad dieléctrica es imprescindible para cualquier ámbito en electromagnetismo, microelectrónica, RF (Radiofrecuencia), óptica, y en general en los problemas de transmisión de información desde un punto de vista electromagnético. Cuando se emplean dieléctricos comerciales para una aplicación particular, estos vienen caracterizados por el fabricante, que emplea una técnica determinada de medida de la permitividad. Sin embargo, cuando se desea conocer la permitividad de dieléctricos que no son comerciales, se hace conveniente emplear técnicas de caracterización específicas para poder estimar su valor con precisión. La aplicación concreta donde surge este TFG (Trabajo Fin de Grado), que es donde es necesario aplicar las técnicas de medida, es en el diseño de sensores de RF basados en estructuras metamateriales, en ámbitos como el industrial o el biomédico, con aplicaciones tales como la detección de sustancias o biomoléculas. El objetivo fundamental de este trabajo es investigar y corroborar técnicas experimentales precisas de caracterización de la permitividad de dieléctricos, en el rango de microondas, con el fin de aplicarlas a substratos (p. ej., cuarzo, vidrio, silicio puro, etc.) que presentan ciertas ventajas si se utilizan como substrato para los sensores mencionados. Se trata de materiales paramagnéticos de bajas pérdidas cuya permitividad dieléctrica relativa, εr, se desconoce a priori y se desea averiguar. Por ejemplo, un caso interesante en el vidrio es que puede usarse como substrato en la detección de proteínas, con ciertas técnicas como la espectrometría de masas y la resonancia de plasmones superficiales. Se ha llevado a cabo una metodología exhaustiva para la selección de la técnica adecuada, en tres niveles distintos (de la teoría a la práctica). En el primer nivel, teórico, se ha descrito y discutido una serie de alternativas que se emplean en la actualidad. En el segundo nivel, de simulación electromagnética, se han comparado las prestaciones de distintas técnicas seleccionadas, basadas en tecnologías planas, y se han descartado las que no interesaban. Y en el tercer nivel, de medida experimental con el VNA (Analizador Vectorial de Redes), finalmente se han comprobado los resultados previos y se han seleccionado las técnicas óptimas. Tanto en simulación como en medida en el laboratorio, primeramente se ha determinado la εr de varios materiales de RF estandarizados y disponibles en el laboratorio a partir de los parámetros de scattering, [S]. A continuación, la εr obtenida se ha contrastado con la proporcionada por el fabricante, para cada uno de las variantes utilizadas. Se ha demostrado la fiabilidad de dos técnicas concretas: el resonador en “T” y el resonador en anillo. Como complemento a lo anterior, se han realizado pruebas del resonador en anillo en los substratos que nos interesan, que en este caso han sido el vidrio borosilicato y el cuarzo, ya que disponemos de sus muestras. La dificultad añadida por la capa de Kapton®, que debe adherirse a los substratos para poder metalizarlos, hace que se deban investigar soluciones ad hoc para obtener una caracterización más precisa.Ingeniería en Tecnologías de Telecomunicació

An IoT reader for wireless passive electromagnetic sensors

This article belongs to the Special Issue State-of-the-Art Sensors Technology in Spain 2016.In the last years, many passive electromagnetic sensors have been reported. Some of these sensors are used for measuring harmful substances. Moreover, the response of these sensors is usually obtained with laboratory equipment. This approach highly increases the total cost and complexity of the sensing system. In this work, a novel low-cost and portable Internet-of-Things (IoT) reader for passive wireless electromagnetic sensors is proposed. The reader is used to interrogate the sensors within a short-range wireless link avoiding the direct contact with the substances under test. The IoT functionalities of the reader allows remote sensing from computers and handheld devices. For that purpose, the proposed design is based on four functional layers: the radiating layer, the RF interface, the IoT mini-computer and the power unit. In this paper a demonstrator of the proposed reader is designed and manufactured. The demonstrator shows, through the remote measurement of different substances, that the proposed system can estimate the dielectric permittivity. It has been demonstrated that a linear approximation with a small error can be extracted from the reader measurements. It is remarkable that the proposed reader can be used with other type of electromagnetic sensors, which transduce the magnitude variations in the frequency domain

A Near-Field Split-Ring Resonator-Based Monopole Sensor for Permittivity Characterization

Many passive electromagnetic sensors have been recently studied. One of their advantages is [...

An IoT Reader for Wireless Passive Electromagnetic Sensors

In the last years, many passive electromagnetic sensors have been reported. Some of these sensors are used for measuring harmful substances. Moreover, the response of these sensors is usually obtained with laboratory equipment. This approach highly increases the total cost and complexity of the sensing system. In this work, a novel low-cost and portable Internet-of-Things (IoT) reader for passive wireless electromagnetic sensors is proposed. The reader is used to interrogate the sensors within a short-range wireless link avoiding the direct contact with the substances under test. The IoT functionalities of the reader allows remote sensing from computers and handheld devices. For that purpose, the proposed design is based on four functional layers: the radiating layer, the RF interface, the IoT mini-computer and the power unit. In this paper a demonstrator of the proposed reader is designed and manufactured. The demonstrator shows, through the remote measurement of different substances, that the proposed system can estimate the dielectric permittivity. It has been demonstrated that a linear approximation with a small error can be extracted from the reader measurements. It is remarkable that the proposed reader can be used with other type of electromagnetic sensors, which transduce the magnitude variations in the frequency domain

A 12-gene pharmacogenetic panel to prevent adverse drug reactions: an open-label, multicentre, controlled, cluster-randomised crossover implementation study

© 2023Background: The benefit of pharmacogenetic testing before starting drug therapy has been well documented for several single gene–drug combinations. However, the clinical utility of a pre-emptive genotyping strategy using a pharmacogenetic panel has not been rigorously assessed. Methods: We conducted an open-label, multicentre, controlled, cluster-randomised, crossover implementation study of a 12-gene pharmacogenetic panel in 18 hospitals, nine community health centres, and 28 community pharmacies in seven European countries (Austria, Greece, Italy, the Netherlands, Slovenia, Spain, and the UK). Patients aged 18 years or older receiving a first prescription for a drug clinically recommended in the guidelines of the Dutch Pharmacogenetics Working Group (ie, the index drug) as part of routine care were eligible for inclusion. Exclusion criteria included previous genetic testing for a gene relevant to the index drug, a planned duration of treatment of less than 7 consecutive days, and severe renal or liver insufficiency. All patients gave written informed consent before taking part in the study. Participants were genotyped for 50 germline variants in 12 genes, and those with an actionable variant (ie, a drug–gene interaction test result for which the Dutch Pharmacogenetics Working Group [DPWG] recommended a change to standard-of-care drug treatment) were treated according to DPWG recommendations. Patients in the control group received standard treatment. To prepare clinicians for pre-emptive pharmacogenetic testing, local teams were educated during a site-initiation visit and online educational material was made available. The primary outcome was the occurrence of clinically relevant adverse drug reactions within the 12-week follow-up period. Analyses were irrespective of patient adherence to the DPWG guidelines. The primary analysis was done using a gatekeeping analysis, in which outcomes in people with an actionable drug–gene interaction in the study group versus the control group were compared, and only if the difference was statistically significant was an analysis done that included all of the patients in the study. Outcomes were compared between the study and control groups, both for patients with an actionable drug–gene interaction test result (ie, a result for which the DPWG recommended a change to standard-of-care drug treatment) and for all patients who received at least one dose of index drug. The safety analysis included all participants who received at least one dose of a study drug. This study is registered with ClinicalTrials.gov, NCT03093818 and is closed to new participants. Findings: Between March 7, 2017, and June 30, 2020, 41 696 patients were assessed for eligibility and 6944 (51·4 % female, 48·6% male; 97·7% self-reported European, Mediterranean, or Middle Eastern ethnicity) were enrolled and assigned to receive genotype-guided drug treatment (n=3342) or standard care (n=3602). 99 patients (52 [1·6%] of the study group and 47 [1·3%] of the control group) withdrew consent after group assignment. 652 participants (367 [11·0%] in the study group and 285 [7·9%] in the control group) were lost to follow-up. In patients with an actionable test result for the index drug (n=1558), a clinically relevant adverse drug reaction occurred in 152 (21·0%) of 725 patients in the study group and 231 (27·7%) of 833 patients in the control group (odds ratio [OR] 0·70 [95% CI 0·54–0·91]; p=0·0075), whereas for all patients, the incidence was 628 (21·5%) of 2923 patients in the study group and 934 (28·6%) of 3270 patients in the control group (OR 0·70 [95% CI 0·61–0·79]; p <0·0001). Interpretation: Genotype-guided treatment using a 12-gene pharmacogenetic panel significantly reduced the incidence of clinically relevant adverse drug reactions and was feasible across diverse European health-care system organisations and settings. Large-scale implementation could help to make drug therapy increasingly safe. Funding: European Union Horizon 2020