Parallel-pumped nonlinear loss effects for polycrystalline yttrium iron garnet in the high-power microwave environment

Abstract

In this study, the parallel-pumped nonlinear (NL) loss effects of polycrystalline Yttrium Iron Garnet (YIG) material caused by the high-power microwave (HPM) were explored for the first time. In terms of the coupling process of spin waves and electromagnetic waves, the improved ferrite NL theory encompassing the input microwave waveform parameters (pulse duration and power) was developed. The theoretical and experimental results indicated that the critical threshold power of the NL effect is approximately inversely proportional to incident microwave pulse with a duration below 80 ns, demonstrating the features of the energy threshold. Furthermore, the theoretical calculation and the high-power measurements show that the polycrystalline YIG sample exhibits a relatively stable microwave power loss trend in the HPM environment with input power of 160 W–400 W. The influence of the external magnetic bias field on the YIG nonlinear effects was also carried out for comparative analysis. This research not only expanded the NL loss theory of ferrite in the nanosecond-level microwave environment but also offered a potential limiting protection application against HPM electromagnetic environment threats.