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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↗

arXiv2024

Microwave Remote Sensing of Soil Moisture, Above Ground Biomass and Freeze-Thaw Dynamic: Modeling and Empirical Approaches

Human actions have accelerated changes in global temperature, precipitation patterns, and other critical Earth systems. Key markers of these changes can be linked to the dynamic of Essential Climate Variables (ECVs) and related quantities, such as Soil Moisture (SM), Above Ground Biomass (AGB), and Freeze-Thaw (FT) Dynamics. These variables are crucial for understanding global climate changes, hydrological and carbon cycles included. Monitoring these variables helps to validate climate models and inform policy decisions. Technologies like microwave remote sensing provide critical tools for monitoring the effects of human activities on these variables at a global scale. Other than proper tachenological developments, the study of ECVs requires suitable theoretical retrieval tools, which leads to the solutions of inverse problems. In this brief survey, we analyze and summarize the main retrieval techniques available in the literature for SM, AGB, and FT, performed on data collected with microwave remote sensing sensors. Such methods will be some of the fundamental algorithms that can find applications in the research activities of the interdisciplinary, curiosity-driven, project {\it REmote sensing daTa INversion with multivariate functional modeling for essential climAte variables characterization (RETINA)}, recently funded by the European Union under the Italian National Recovery and Resilience Plan of NextGenerationEU, under the Italian Ministry of University and Research. The main goal of RETINA, in which three research units from three different italian universities are involved, is to create innovative techniques for analyzing data generated by the interaction of electromagnetic waves with the Earth's surface, applying theoretical insights to address real-world challenges.

math.NA↗