29 citations · 253 across the 23 of their papers we have counts for
23 papers
A Dual-Mode FM/AM Modulator Based on a Time-Varying Inverting Integrator
Azalía G. Gil, Alfonso T. Muriel-Barrado, Mario Pérez-Escribano +2
This paper presents the analysis, design, fabrication, and experimental validation of a dual-mode frequency/amplitude modulator based on a time-modulated varactor diode. By exploit…
Gain and One-Way Propagation in Synthetically Moving non-Foster Gratings
Antonio Alex-Amor, Carlos Molero, Mario G. Silveirinha
In this paper, we analyze the electromagnetic properties of space-time grooved metal surfaces governed by uniform-velocity modulations. We begin by deriving the electromagnetic fie…
Time-Controlled Resonances in 2-D Metasurfaces via Equivalent Circuits
J. Rafael Sánchez-Martínez, Mario Pérez-Escribano, Antonio Alex-Amor +2
This work introduces a semi-analytical frequency-domain framework for the analysis of two-dimensional, time-modulated (2+1)-D metasurfaces controlled by PIN diodes. The formulation…
Gamification in Radiocommunications: A Board Game Approach to Boost Engagement and Learning
Ana S. Domenech, Antonio Alex-Amor
Courses in electromagnetism and related technical subjects are often dominated by lecture-heavy instruction and complex mathematical concepts, which can make it difficult for stude…
Temporal Paraxial Optics under Adiabatic Modulations
Antonio Alex-Amor, Carlos Molero
This paper presents a temporal paraxial formulation for the propagation of ultrashort optical pulses in time-modulated media with slowly varying refractive index. By deriving the p…
Transfer ABCD Matrix for Time-Varying Media and Time Crystals
Carlos Molero, Pablo H. Zapata-Cano, Antonio Alex-Amor
This paper introduces a formal definition of the transfer ABCD parameters in time-varying electromagnetic systems. The formal definition comes after the rearrangement of the fields…
Kapitza-Inspired Stabilization of Non-Foster Circuits via Time Modulations
Antonio Alex-Amor, Grigorii Ptitcyn, Nader Engheta
With his formal analysis in 1951, the physicist Pyotr Kapitza demonstrated that an inverted pendulum with an externally vibrating base can be stable in its upper position, thus ove…
Transient States to Control the Electromagnetic Response of Space-time Dispersive Media
Pablo H. Zapata-Cano, Salvador Moreno-Rodríguez, Stamatios Amanatiadis +3
In this paper, we study the dynamic formation of transients when plane waves impinge on a dispersive slab that abruptly changes its electrical properties in time. The time-varying…
Space-time Metallic Metasurfaces for Frequency Conversion and Beamforming
Salvador Moreno-Rodríguez, Antonio Alex-Amor, Pablo Padilla +2
This paper details a class of metal-based space-time metasurfaces for application in wireless communications scenarios. Concretely, we describe space-time metasurfaces that periodi…
Analytical Framework to Model Reconfigurable Metasurfaces including Lumped Elements
Mario Pérez-Escribano, Salvador Moreno-Rodríguez, Carlos Molero +3
This paper presents an analytical framework, based on Floquet modal expansions of the electromagnetic fields and equivalent circuits, to model reconfigurable metasurfaces loaded wi…
Joint Ultra-wideband Characterization of Azimuth, Elevation and Time of Arrival with Toric Arrays
Alejandro Ramírez-Arroyo, Antonio Alex-Amor, Rubén Medina +2
In this paper, we present an analytical framework for the joint characterization of the 3D direction of arrival (DoA), i.e., azimuth and elevation components, and time of arrival (…
Analytical Equivalent Circuits for Three-dimensional Metamaterials and Metagratings
Antonio Alex-Amor, Salvador Moreno-Rodríguez, Pablo Padilla +2
In recent times, three-dimensional (3D) metamaterials have undergone a revolution driven mainly by the popularization of 3D-printing techniques, which has enabled the implementatio…
Analysis of Metallic Space-Time Gratings using Lorentz Transformations
Antonio Alex-Amor, Carlos Molero, Mário G. Silveirinha
This paper presents an analytical framework for the study of scattering and diffraction phenomena in spacetime-modulated metallic gratings. Using a Lorentz transformation, it is sh…
Time-periodic Metallic Metamaterials defined by Floquet Circuits
Salvador Moreno-Rodríguez, Antonio Alex-Amor, Pablo Padilla +2
In this paper, we study the scattering and diffraction phenomena in time-modulated metamaterials of metallic nature by means of Floquet equivalent circuits. Concretely, we focus on…
Joint Direction-of-Arrival and Time-of-Arrival Estimation with Ultra-wideband Elliptical Arrays
Alejandro Ramírez-Arroyo, Antonio Alex-Amor, Pablo Padilla +1
This paper presents a general technique for the joint Direction-of-Arrival (DoA) and Time-of-Arrival (ToA) estimation in multipath environments. The proposed ultra-wideband techniq…
Diffraction Phenomena in Time-varying Metal-based Metasurfaces
Antonio Alex-Amor, Salvador Moreno-Rodriguez, Pablo Padilla +2
This paper presents an analytical framework for the analysis of time-varying metal-based metamaterials. Concretely, we particularize the study to time-modulated metal-air interface…
3-D Metamaterials: Trends on Applied Designs, Computational Methods and Fabrication Techniques
Antonio Alex-Amor, Angel Palomares-Caballero, Carlos Molero
Metamaterials are artificially engineered devices that go beyond the properties of conventional materials in nature. Metamaterials allow the creation of negative refractive indexes…
Cross-polarization Control in FSSs by means of an Equivalent Circuit Approach
Carlos Molero, Antonio Alex-Amor, Francisco Mesa +2
This paper presents an efficient equivalent circuit approach (ECA), based on a Floquet modal expansion, for the study of the co- and cross-polarization in frequency selective surfa…
Generalized Director Approach for Liquid-Crystal-Based Reconfigurable RF Devices
Antonio Alex-Amor, Angel Palomares-Caballero, Antonio Palomares +3
This letter presents a closed-form integral-equation formulation that models the director tilting in nematic liquid crystals. The proposed formulation is computationally efficient…
Glide-Symmetric Metallic Structures with Elliptical Holes for Lens Compression
Antonio Alex-Amor, Fatemeh Ghasemifard, Guido Valerio +4
In this paper, we study the wave propagation in a metallic parallel-plate structure with glide-symmetric elliptical holes. To perform this study, we derived a mode-matching techniq…
Dispersion and Filtering Properties of Rectangular Waveguides Loaded With Holey Structures
Ángel Palomares-Caballero, Antonio Alex-Amor, Pablo Padilla +1
This paper analyzes thoroughly the dispersion and filtering features of periodic holey waveguides in the millimeter-wave frequency range. Two structures are mainly studied dependin…
Exploring the Potentials of the Multi-modal Equivalent Circuit Approach for Stacks of 2-D Aperture Arrays
Antonio Alex-Amor, Francisco Mesa, Ángel Palomares-Caballero +2
Many frequency selective surface (FSS) structures are based on the use of a single periodic array of slot/apertures in a conducting sheet embedded in a layered medium. However, it…
Low-Loss Reconfigurable Phase Shifter in Gap-Waveguide Technology for mm-Wave Applications
Á. Palomares-Caballero, A. Alex-Amor, P. Escobedo +2
In this brief, we present a low-loss mechanically reconfigurable phase shifter implemented in gap-waveguide technology for mm-wave frequencies. The proposed design gives a practica…