Conformal Radiation-type Programmable Metasurface for Agile Millimeter-Wave OAM Generation

Research, Год журнала: 2025, Номер 8

Опубликована: Янв. 1, 2025

Since the scarcity of bandwidth resources has become increasingly critical in modern communication systems, orbital angular momentum (OAM) with a higher degree freedom information modulation promising solution to alleviate shortage spectrum resources. Consequently, integration OAM millimeter-wave technology emerged as focal point next-generation research. Recently, programmable metasurfaces have gained considerable attention essential devices for generation due real-time tunability, but their profiles are relatively high result external feed source. This paper proposes conformal radiation-type metasurface operating band. By employing series–parallel hybrid network replace conventional sources, overall profile system can be reduced less than 0.1 λ . Furthermore, proposed innovation design could also achieve cross-shaped architecture, which is ultraportable and very effective integrating front ends satellites or aircraft eliminating issues such source blockage well energy spillover losses metasurfaces. The realized gain 22.54 dB an aperture efficiency 21.75%, thus generating high-purity waves topological charges l = 0, +1, +2, +3. Additionally, by incorporating beam scanning techniques, deflected accommodate scenarios moving receivers, demonstrating substantial potential future high-speed wireless applications.

Язык: Английский

A Single‐Layer Spin‐Multiplexed Metasurface for Chameleon‐Like Electromagnetic Camouflage and Low Detectability

Laser & Photonics Review, Год журнала: 2025, Номер unknown

Опубликована: Фев. 16, 2025

Abstract This paper introduces a novel methodology for designing electromagnetic (EM) camouflage metasurfaces. Initially, temperature‐sensitive resistor is embedded within the chiral atom, allowing temperature‐induced variations to selectively modulate reflection amplitude of left‐handed circularly polarized (LCP) wave. Subsequently, reflected phases both right‐handed (RCP) and LCP waves are independently modulated, ensuring that two span full 2π range. Ultimately, atoms strategically arranged facilitate realization various functions. As proof concept, metasurface demonstrating chameleon‐like low detectability simulated, fabricated, experimentally validated. When wave incident, retroreflection occurs at specific angle. Similar chameleon, radar cross section (RCS) varies in response temperature changes. an RCP average RCS reduction greater than 12 dB achieved X Ku band. Furthermore, incident angle 60°, maintains exceeding 8.5 dB. Both simulation experimental results confirm proposed effectively combines advantages with broadband, large‐angle detectability, its potential applications camouflage.

Язык: Английский

Quasi-Classical Models of Nonlinear Relaxation Polarization and Conductivity in Electric, Optoelectric, and Fiber Optic Elements Based on Materials with Ionic–Molecular Chemical Bonds

Applied Sciences, Год журнала: 2024, Номер 14(24), С. 11830 - 11830

Опубликована: Дек. 18, 2024

A generalized scientific review with elements of additions and clarifications has been carried out on the methods theoretical research electrophysical properties crystals ionic–molecular chemical bonds (CIMBs). The main tools adopted are quasi-classical kinetic theory as applied to ionic subsystems relaxing in layered dielectrics (natural silicates, crystal hydrates, various types ceramics, perovskites) an electric field. universal (applicable for any CIMBs class crystals) nonlinear equation practical importance constructed. This describes, complex Poisson equation, mechanism ion-relaxation polarization conductivity a wide range polarizing field parameters (0.1–1000 MV/m) temperatures (1–1550 K). physical model is based system non-interacting ions (due low concentration crystal) moving one-dimensional, spatially periodic crystalline potential field, perturbed by external energy spectrum assumed be continuous. Elements quantum mechanical used mathematically describe influence tunnel transitions hydrogen (protons) during interaction proton anion hydrogen-bonded (HBC) dielectric region nitrogen (50–100 K) helium (1–10 temperatures. mathematical solution Fokker-Planck equations, solved perturbation (via expanding solutions into infinite power series small dimensionless parameter). Theoretical frequency temperature spectra loss tangent were constructed analyzed, molecular relaxers calculated, nature maxima experimental losses number HBC was discovered. low-temperature maximum, which caused tunneling protons absent spectra, theoretically calculated investigated. most effective areas technical application results obtained identified. equations recurrent formulas study optical effects laser technologies radio wave microwave signal control systems greatest interest.

Язык: Английский