Verification of spinwave excitation in coaxial gyromagnetic nonlinear transmission lines.

The knowledge of physical mechanism of microwave generation in coaxial gyromagnetic nonlinear transmission lines (GNLTLs) is not complete up until now, especially the action of spinwave excitation during this process. In this paper, control experiments on different groups of GNLTLs with a single variable of NiZn ferrite material spinwave linewidth ΔHk are proposed as an indirect way to demonstrate this microscopic process. Comparative analyses of different groups of GNLTL experimental results are conducted to clarify the existence and effect of spinwave excitation. Theoretical treatment of conditions of spinwave excitation in GNLTLs is derived to explain the experimental results. It is illustrated that spinwave can be excited when the synchronism condition between the working frequency of GNLTL and the spinwave frequency spectrum is satisfied. The unstable spinwave excitation will consume the RF energy of GNLTLs heavily and cause a rapid decrease in RF oscillation.