Programa del congreso

El aumento de las enfermedades óseas debido al envejecimiento poblacional requiere la búsqueda de nuevas técnicas de implantes, como son los andamios óseos. En esta contribución se propone el diseño de andamios óseos autosensores que funcionan como sensores pasivos de microondas sin necesidad de electrónica adicional, a la vez que mantienen sus características estructurales y favorecen la regeneración ósea. Para ello, se diseña un resonador dieléctrico (RD) poroso que se puede fabricar mediante técnicas de fabricación aditiva (impresión 3D), resultando en una estructura personalizable y de bajo coste. Se propone una prueba de concepto mediante la que se observa que la simulación de la regeneración ósea produce un cambio en la frecuencia de resonancia y ancho de banda del RD poroso. Estos resultados experimentales demuestran la validez de esta técnica para conseguir una monitorización no invasiva, continua, en tiempo real y barata mediante radiación no ionizante para realizar el seguimiento del proceso de regeneración ósea.

This paper presents a study related to the implementation of realistic breast models for the training and optimization of non-invasive microwave-based breast tumour detection systems. The use of these synthetic models, with similar properties to the biological tissues, is essential in order to evaluate the performance of tumour detection systems in controlled laboratory environments, prior to testing with patients in clinical settings.

In this paper, mixtures of commonly used materials have been used in the implementation of the synthetic tissues. From these mixtures, complex and realistic breast models with two and three layers have been implemented. The developed breast models have been analysed with a microwave medical imaging system. The signals obtained have been processed with complex techniques to detect both the breast tissues and, more importantly, to detect and locate the tumour tissue. The results obtained are promising, predicting good properties of these systems in the detection of breast tumours, especially in the screening phase.

We present a numerical framework to simulate the nonlinear electromagnetic response of biological cells subjected to microwave excitation. Building on recent experimental studies that detect third-order intermodulation products from living cells, our model captures the electrodynamic behavior of membranes via time-dependent conductivity and permittivity changes associated with electroporation. The governing equations are formulated in the time domain, based on a full-wave Maxwell model for TE polarization, and discretized using a semi-implicit scheme coupled with a high-order fast direct solver. Validation against reference solutions in both damped and lossless configurations demonstrates high accuracy and numerical stability. We further illustrate the nonlinear current response of a single cell placed between parallel electrodes under time-varying voltage stimulation. The results highlight the potential of this computational approach to predict nonlinear microwave interactions in cellular environments and to complement experimental microfluidic platforms for future sensing and biomedical applications.

Este trabajo presenta un novedoso sensor de microondas en guía de ondas rectangular no uniforme para la caracterización de las propiedades dieléctricas de materiales. Este describe el principio teórico de funcionamiento del sensor. Las dimensiones de la estructura se han optimizado para caracterizar las propiedades dieléctricas de aceites vegetales. La respuesta del sensor se ha validado midiendo un sustrato sólido con propiedades dieléctricas similares a las de estos aceites. La permitividad relativa del material que rellena la estructura se obtiene mediante la fase del coeficiente de reflexión, que se mide y compara con el análisis teórico y las simulaciones.

This work presents an improved low-cost system for measuring the complex permittivity of liquids and semi-solids using an open-ended coaxial probe. The new system replaces the previous SMA connector with a 0.047" semi-rigid coaxial cable assembly to extend the frequency range up to 20 GHz. The performance of the proposed system is evaluated by comparing measurements of various liquids acetone, methanol, ethanol, propan-1-ol, propan-2-ol, Triton, sunflower oil, saline water, and a 50% water-Triton mixture with those obtained using a commercial open-ended coaxial probe. The results demonstrate the accuracy and reliability of the proposed system, showing excellent agreement with commercial measurements, especially in the frequency range of 500 MHz to 20 GHz. This study highlights the potential of the proposed system as a cost-effective alternative for dielectric characterization, making it suitable for use in laboratories with limited resources.

Accurate sleep stage classification plays a significant role in sleep analysis and sleep disorder diagnosis. Traditional manual annotation of polysomnography (PSG) recordings is labour-intensive and time-consuming, prompting the adoption of automated sleep scoring methods. Although many approaches have been developed, challenges remain in terms of the temporal dependence of PSG signals and computational efficiency. To address these limitations, we propose a novel sleep stage classification model with strong clinical feasibility that balances performance and computational cost. Our method utilises two hierarchical components to process multichannel PSG recordings. First, handcrafted features are extracted in both time and frequency domains in accordance with the American Academy of Sleep Medicine (AASM) guidelines. By including the neighbouring epochs, it preserves temporal correlations. Second, an extreme gradient boosting (XGBoost) classifier is employed for final classification results. Experimental evaluations demonstrate that the proposed model outperforms state-of-the-art approaches in classification performance and computational efficiency, highlighting its potential for real-world clinical implementation.