2026/07/30 by Serhii Karelin, Ivan Onishchenko
Physics and Astronomy · #physics.plasm-ph #msc:78M20
Submitted to IEEE Transactions on Plasma Science (Manuscript ID: TPS18901). Materials of this paper were presented as a poster report "2D/3D FDTD Modeling of Coaxial Waveguide with Magnetized Nonlinear Ferrite and Slow-Wave Structure" at the XXXII International Workshop on Optical Wave & Waveguide Theory and Numerical Modelling, 8-10 April 2026, Lausanne, Switzerland (https://owtnm26.epfl.ch/)
arxiv created 2026/07/30 · arxiv updated 2026/07/31
A coaxial gyromagnetic nonlinear transmission line (GNLTL) enables pulse-front compression and oscillation packet generation in the 0.3-10 GHz range. Numerical modeling of such systems typically employs a 2D axially symmetric FDTD scheme coupled with the parallel solution of full non-linearized Landau-Lifshitz-Gilbert equations. Previous studies have shown that using an insulating dielectric with a permittivity ε>60 enables the generation of long-lasting oscillations via a Cherenkov-like effect. However, practical implementation is limited due to the severe high-frequency losses inherent in materials with such extreme permittivity, like water. To overcome this limitation and enhance performance, we propose a novel design utilizing a spiral central conductor to mimic a high-permittivity environment, with the ferrite placed inside the spiral. Due to the loss of axial symmetry, the FDTD model was extended to 3D coordinates. Simulations confirm that the spiral conductor configuration generates a prolonged oscillation packet similar to that of a high-permittivity dielectric waveguide, but with significantly reduced losses and improved energy transfer efficiency.