Development Of Low Loss YIG Material And Its Application In Circulator

With the development of a new generation of microwave devices toward miniaturization and integration,the comprehensive properties of YIG ferrite materials,such as ferromagnetic resonance linewidth,dielectric loss,saturation magnetization,Curie temperature,etc,need to meet higher performance requirements.In this paper,the target YIG ferrite material was prepared by the solid-state reaction method,and the research of low loss of YIG material and the design of circulator were mainly discussed.Firstly,the influence of iron deficiency on phase composition,microstructure and electromagnetic properties of YIG ferrite material was studied.The study show that appropriate iron deficiency is helpful to reduce the linewidth and dielectric loss of ferromagnetic resonance.However,excessive iron deficiency will lead to the formation of another phase of YFeO₃ and increase of microwave magnetic loss.Furthermore,the effect of oxygen flow rate on the properties of YIG-ferrite material during presintering was studied.The results show that the appropriate oxygen flow rate can improve the density of the sample.When the iron deficiency x=0.075 and the oxygen flow rate is150 m L/min,the linewidth of ferromagnetic resonance is 29Oe.Next,the effects of Ca-Sn and Ca-Ti co-substitution on the properties of YIG-ferrite materials was studied.It was found that the saturation magnetization increase when Sn⁴⁺or Ti⁴⁺ions replace Fe³⁺ions at the octahedral position of garnet structure,while the microwave dielectric loss and ferromagnetic resonance linewidth decrease significantly.Further decomposition of the source of ferromagnetic resonance linewidth shows that stomatal width is the main part and its variation trend is similar to that of porosity,and the anisotropic width decreases with the increase of the amount of substitution.Both kinds of ions can replace the Fe³⁺in the A position of the octahedron of YIG sample,which increases the saturation magnetization.The dielectric loss and linewidth of ferromagnetic resonance can be reduced obviously when the amount of substitution is small.When x=0.1,the ferromagnetic resonance linewidth is the lowest(22 Oe).When x=0.15,the dielectric loss is the lowest(8×10^-5).The ferromagnetic resonance linewidth of Ti⁴⁺ion-substituted YIG sample is the minimum(26Oe)at x=0.1.At x=0.15,the dielectric loss is the minimum(3×10^-4).In addition,it was noted that in a certain range,the lattice expansion is caused by the substitution of two ions,the activity of YIG material increases,and the sintering temperature decreases to some extent.Finally,according to the working principle of the circulator,the developed YIG ferrite material was used as the substrate to complete the model construction and optimization in HFSS3D simulation software.The final simulation results are as follows:relative bandwidth?30%;return loss?-18dB;isolation degree?-18dB;The insertion loss is?-0.5dB,which indicates that the material can be used in the manufacture of circulator and has good performance.