Study On LiZn Ferrite And Its Application In Ka Band Phase Shifter

At present,Ka-band phased array radar and passive phased array radar are widely used.Microwave ferrite phase shifter is an important part of phased array radar,so it is of great significance to further improve the performance,reduce costs and reduce the size of microwave ferrite phase shifter.The ferrite phase shifter is a microwave device based on the good properties of ferrite material.The performance of ferrite material also plays a pivotal role in the phase shifter and even the phased array radar.How to develop a gyromagnetic ferrite material with high saturation magnetization,high temperature stability,low dielectric loss and the ferromagnetic resonance linewidth is a key research topic.In this paper,the preparation technology and main formula of LiZn ferrite materials for Ka-band phase shifter are studied.Based on the prepared LiZn ferrite,Ka-band phase shifter was designed and simulated.The experimental results show that:?1?Iron deficiency of LiZn ferrite produces ion vacancy,promotes sintering,makes grain growth uniform and dense,increases saturation magnetization and remanence ratio,and reduces ferromagnetic resonance line width,and increases the resistivity.However,excessive iron deficiency results in uneven microstructure,magnetic properties deteriorate,ferromagnetic resonance line width increases.At the same time,magnetocrystalline anisotropy constant was calculated via approximation saturation law.Anisotropy constant reduces with the increase in the amount of iron deficiency.Linewidth was separated.The results show that porosity linwidth reaches about 80%,which is the dominant factor for ferromagnetic resonance line-width.?2?Co ion substitution promotes grain growth,increases saturation magnetization of the material,and reduces coercivity,but rapidly increases magnetocrystalline anisotropy constant,resulting in increasing ferromagnetic resonance line width.?3?The substitution of Mn ions increases resistivity of the material,but at the same time,saturation magnetization and remanence ratio of the material decreases and ferromagnetic resonance line width increases.?4?Bi2O3 additive promotes the solid phase reaction,reduce the sintering temperature,increases saturation magnetization and remanence,and reduces the coercivity.The calcination temperature and the ball material can affect the activity of the powder,and can control the grain growth and improve the microstructure of the material.The sintering temperature and the heating rate can affect the growth of the grains by affecting the solid-phase reaction rate of the material.Therefore,LiZn ferrite material with uniform microstructure and excellent magnetic properties can be obtained by using suitable preparation process?Fe₂O₃ raw material,calcination temperature,ball mill steel material,sintering temperature and heating rate?.Finally,Ka-band ferrite phase shifter was designed and simulated by Ansoft HFSS software.The simulated results,at 25?,show that at 33.5GHz 34.5GHz,return loss S₁₁ <-26 dB,VSWR <1.1,insertion loss | S21 | <1.55 dB,and phase shift at 34 GHz reaches 450 °.