Modelado de estructuras FSS mediante resonadores sublambda para el diseño de filtros y antenas integrados en guías de onda

Abstract

This thesis presents the development, modeling, and validation of frequency-selective surfaces (FSS), microwave filters based on metamaterial structures, and waveguide antennas. A theoretical model is proposed for the implementation of filters in waveguides, employing bandwidth control through the use of metallic layers with CSRR and Omega-type cells, as well as leveraging mirror symmetry for coupling and enhanced selectivity. The study analyzes the electric and magnetic polarizability of the metamaterial elements and their impact on the transmission and reflection of waves, integrating these parameters into the design of compact and highly selective devices. Based on the mathematical description of scattering parameters, models are established that allow for the prediction and adjustment of the resonant response of the cells, optimizing both the selectivity and performance of the filters, as well as beam control in antennas. The model validation is carried out through electromagnetic simulations, fabrication, and experimental characterization of filters and antennas in WR340 waveguide. For antennas, arrays of six CELC cells were implemented for beam steering, and for filters, CSRR and Omega cells with mirror symmetry were employed in both single-layer and double-layer configurations. The experimental and numerical results obtained demonstrate the viability of the proposed approach for controlling bandwidth and beam direction in microwave devices. The use of mirror symmetry and the optimization of the cell polarizability enable robust tuning of the frequency response and efficient design of compact filters and antennas. In conclusion, the work presented constitutes an advanced tool for the design and optimization of filters and antennas, providing innovative solutions for the development of microwave devices, with experimental validation and applications in communication systems, radars, and advanced sensors.