Test and Analysis on the Gyromagnetic Nonlinear Transmission Lines With Different Magnetic Cores

Miniaturization and frequency tunability have become two important development directions of high-power microwave technology. The wideband high-power microwave system based on gyromagnetic nonlinear transmission line (GNLTL) has been proven to have the potential to produce smaller physical size and lighter weight. The GNLTL is a special wideband source whose output frequency can be tuned online by changing the biasing magnetic field. The working mechanism of a GNLTL is related to the damping precession of magnetic moments, and the parameters of magnetic material have important effects on the output microwaves. However, the details of these effects are still not fully clear. This article tested and analyzed the effects of three key gyromagnetic parameters on the output microwaves, namely, saturation magnetization (
${M}_{s}$
), spin wave linewidth (
$\Delta {H}_{k}$
), and ferromagnetic resonance (FMR) linewidth (
$\Delta {H}$
). The results showed that the cores with higher
${M}_{s}$
and lower
$\Delta {H}$
help to increase the peak power. The spin wave linewidth
$\Delta {H}_{k}$
has little effect on the peak power, but the cores with lower
$\Delta {H}_{k}$
can expand the frequency tuning range. The experimental results and theoretical analyses help to the selection of magnetic cores and the predesign of the GNLTLs.