Enhanced microwave performance of nano-TiO2 modified lithium ferrites for high-power applications

Abstract

To meet the application requirements of high-power microwave devices, the effects of anatase nano-TiO₂ doping on the high-power withstanding capability, and microwave loss of lithium ferrites were investigated. The results revealed that an increased proportion of fine grains played a critical role in enhancing spin-wave linewidth (ΔH_k). The Curie temperature rose with increasing doping amount (x), which was attributed to the precipitation of the Bi-enriched ferrite phase. In particular, when x = 0.35, the sample exhibited high spin-wave linewidth (ΔH_k = 14.8 Oe) and low dielectric loss (tanδ_ε = 2.31 ×10⁻⁴), alongside a significant reduction in ferromagnetic resonance linewidth (ΔH = 88 Oe). Leveraging these properties, a classic high-power latching phase shifter was designed. The device achieved large phase shift (>358 °), low insertion loss (<0.84 dB), and small voltage standing wave ratio (<1.23). These excellent performances highlight the promising prospects of nano-TiO₂ modified lithium ferrites in high-power microwave device applications.