arXiv subjects

Guido Valerio

Publications and source records attributed to Guido Valerio.

3 recordsLinked to original sources

arXiv2025

Leaky Mode Generation by means of All-Metal Corrugated Slotted Parallel-Plate Waveguides

Periodic leaky-wave antennas can be realized with planar low-profile structures supporting the generation of highly directional beams with frequency scanning from backward to forward directions. We propose a method to generate leaky modes with continuous scanning with an all-metal periodic 2-D (i.e., invariant along a direction normal to the propagation) waveguide. Periodic corrugations are introduced to support a slow wave, which is transformed with periodic slots etched on the top plate into a fast radiating waves. Suitable choices of the corrugation and the slot periods lead to a single fast backward-forward spatial harmonic being responsible for well-defined and directional radiation. This new method is demonstrated here proposing an original unit cell, properly optimized to suppress the open stop band. The analysis and the design is accomplished with a rigorous in house periodic method-of-moment code, allowing for the computation of complex modes in open 2-D waveguides. The leaky-wave antenna is studied and validated by means of full-wave simulations in Ka band. The structure features continuous beam scanning with broadside radiation at 29.7 GHz with beam scanning, realized gain, and efficiency comparable to different antenna technologies having thickness ten times larger.

physics.app-ph↗

arXiv2021

Glide-Symmetric Metallic Structures with Elliptical Holes for Lens Compression

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 technique based on the generalized Floquet theorem for glide-symmetric structures. This mode-matching technique benefits from a lower computational cost since it takes advantage of the glide symmetry in the structure. It also provides physical insight on the specific properties of Floquet modes propagating in these specific structures. With our analysis, we demonstrate that glide-symmetric structures with periodic elliptical holes exhibit an anisotropic refractive index over a wide range of frequencies. The equivalent refractive index can be controlled by tuning the dimensions of the holes. Finally, by combining the anisotropy related to the elliptical holes and transformation optics, a Maxwell fish-eye lens with a 33.33% size compression is designed. This lens operates in a wideband frequency range from 2.5 GHz to 10 GHz.

physics.app-ph↗

arXiv2020

Reconfigurable Waveguides Using Glide-Symmetric Bed of Nails: Design of an All-Metal Switch at Millimetre-Wave Band

A reconfigurable millimeter-wave artificial waveguide using glide-symmetric pin-like contact-less metasurfaces is proposed in order to enable low loss and high-power-handling capability in switching operations. Thanks to the remarkable behaviour of glide symmetry, the meta-structures are used both as wide-band EBG material to confine the field in the guide and as low-dispersive guiding medium filling the guide itself. The reconfigurability is achieved by adjusting the displacement between the metasurfaces. A higher displacement enables propagation within the waveguide and a lower displacement suppresses it. A two-state reconfigurability is therefore designed, allowing the device to act as an on-off switch in the V-band. In particular, a dispersion analysis highlights the potential of such technology to achieve switching operating over a 55-66 GHz frequency range. A complete design including matching mechanism and WR15 feeding is also described and shown to exhibit a $S_{11}<-10$ dB bandwidth from 57.4 to 62.8 GHz. In the "off" state, the switch isolation is better than 65 dB and in the "on" state, the insertion losses are better than 0.7 dB within the entire operating frequency range. The isolation between two adjacent waveguides is also discussed to assess the integration of such a device within a switching network.

eess.SP↗