Programa del congreso

The development of a Leaky-Wave Antenna based

on Bianisotropic Huygens’ Metasurfaces and using GAP waveguide

technology is presented in this work. The waveguide is

designed with horizontal polarization of the mode at 20 GHz,

different than the conventional vertical polarization. Additionally,

a uniform leaky-wave antenna designed just slotting the top

surface of the waveguide is compared with the same structure

but combining the slot with the Huygens’ metasurface which

change the radiation angle of the LWA to the desired broadside

radiation pattern.

We discuss the issue of identifying the forward/backward nature of the modes in bounded one-dimensional periodic structures. This identification relies on the possibility of adequately and uniquely defining the phase velocity in these types of structures. We propose a general definition of phase velocity for scalar one-dimensional waves and show that, according to that general definition, the voltage and current waves in lossless nonhomogeneous transmission lines with positive inductance and capacitance parameters are necessarily forward waves. In more general scenarios, we show that an appropriate definition of the phase velocity can still be found for electromagnetic waves with at least one linearly polarized field and that they also are necessarily forward waves if they propagate through media with positive permittivity and permeability.

Time domain simulations of electromagnetic problems are intrinsically interesting for engineering purposes, not only from the physical point of view but also from the computational effort. These approaches rely on a marching on time schemes where the field solution can be obtained from previous time steps in an increasing manner. However, each new sample requires computations with a small complexity (typically matrix-vector multiplications) but within a large approximation dimension, which clearly deteriorates the simulation time.

A model order reduction approach for finite element method in time domain (FEMTD) simulations for microwave devices using time as a parameter is proposed in this work. This methodology shows the possibility to solve time evolution problems in electromagnetics requiring a small computational effort. Indeed, the system matrices involved in the model order reduction technique are pretty small. This is in contrast to the large dimension matrices arisen in traditional FDTD and FEMTD approaches.

Several microwave circuits, such as an electromagnetic band gap structure and dielectric resonator filter, will show the capabilities and possibilities of this new approach for time domain simulations in electromagnetics.

The motivation behind the research lies in the necessity to identify indoor applications for 6G to contextualize and render practicality to the proposed work. While terahertz communication holds promise for achieving ultra-large bandwidths and Tbit/s speeds, the primary challenge lies in implementing transceivers suitable for integration into indoor and pico-cells WLANs for 6G applications. The proposed FSS architecture addresses these challenges by introducing a low-profile design that not only overcomes volumetric constraints but also reduces system complexity, thus enhancing cost-effectiveness and facilitating mass adoption across diverse technological domains. This innovative approach enables the implementation of dual polarization in both Co-Polar (CP) and Cross-Polar (XP) operations without the need for intricate multiport networks, thereby simplifying the system architecture and enhancing its versatility. The FSS design offers ultra-large bandwidth circular polarization fields in reflection mode, capable of providing two separate bands for each circular polarization, making both CP and XP operations feasible with minimal changes in phase, thereby paving the way for future 6G communications systems. The Design is manufactured and measured, presenting good relation with respect to the simulations

Currently, vortex beams with orbital angular momentum (OAM) are of great interest as they are a key element in increasing the capacity of communication links. This article presents an analytical study comparing the purity of OAM vortex beams generated using a metasurface illuminated with three different excitations. The transmissive metasurface has been designed to operate in the millimeter-wave frequency range, and consist of 33×33 two-layered H-shaped meta-atoms. The phase is implemented following the Pacharatnam-Berry (PB) principle. High OAM purity votex beams are obtained, with values of 75%, 90%, and 95% for the uniform, circular uniform and Gaussian excitations respectively confirming both the correct functionality of the metasurface and the effect that different excitations have on OAM quality.