Saturday 01 February 2025
Researchers at Ukraine’s Kharkiv Institute of Physics and Technology have made significant progress in developing a novel method for generating high-power electromagnetic waves using a coaxial transmission line filled with ferrite material and periodic metal inserts.
The team, led by S.Y. Karelin, has demonstrated the ability to excite weakly damped electromagnetic waves with frequencies between 1.89 GHz and 2.1 GHz, and bandwidths of up to 16%. These waves are generated by feeding high-voltage pulses into a coaxial line filled with an isotropic dielectric material and a set of ferrite rings with a relative permittivity of 16 and a saturated-state permeability of around 4-5.
The researchers used a dual forming line (DFL) as the primary pulse source, which produced an input pulse with a front width of approximately 3 ns and a half-life duration of about 15 ns. This allowed them to increase the amplitude of the excited waves by compressing the pulse front. The team also added a pulse sharpening circuit to enrich the spectral content of the waveform with higher frequencies.
The experiment involved feeding the high-voltage pulses into a coaxial line with an outer diameter of 50.5 mm, filled with an isotropic dielectric material and ferrite rings. The resulting waves were measured using voltage sensors on the outer electrode of the line, which showed that the amplitude of the excited waves reached levels of up to 32 kV, corresponding to a VHF power output of approximately 20 MW.
The researchers also performed numerical simulations using the finite-difference time-domain (FDTD) method to validate their experimental results. These simulations showed good agreement with the experimentally measured waveforms and spectra, including the frequency and bandwidth of the excited waves.
One of the key findings of this research is that the frequency of the excited waves is determined by the properties of the periodic structure (PS) rather than the ferrite material. This suggests that the PS plays a crucial role in shaping the dispersion curve of the quasi-TEM wave in the coaxial line, which in turn affects the frequency and bandwidth of the excited waves.
The team’s results have important implications for the development of compact high-power microwave sources for various applications, including radar systems, communication devices, and medical treatments. By further optimizing the design of the coaxial transmission line and periodic structure, researchers may be able to generate even higher-power electromagnetic waves with narrower spectral bandwidths.
Cite this article: “Generating High-Power Electromagnetic Waves Using Coaxial Transmission Line and Ferrite Material”, The Science Archive, 2025.
High-Power Electromagnetic Waves, Coaxial Transmission Line, Ferrite Material, Periodic Metal Inserts, Weakly Damped, Electromagnetic Waves, Dual Forming Line, Pulse Sharpening Circuit, Finite-Difference Time-Domain Method, Fdtd Simulation
