A Research On The YIG Ferrite And Application Based On LTCC Technology

Low temperature co-firing ceramic technology（LTCC）provides an effective solution for the miniaturization and integration of circulators,phase shifters and other devices in the electronic information industry.Yttrium iron garnet（YIG）has been studied mainly by scholars because of its excellent gyromagnetic properties,low ferromagnetic resonance linewidth and low dielectric loss.However,when LTCC technology is used to manufacture microwave ferrite devices,YIG ferrite could not be co-fired with silver electrode.At the meantime its internal structure was loose and its performance deteriorated.Therefore,this paper mainly focuses on YIG low-temperature sintering,electromagnetic performance optimization and its application in x-band toroidal apparatus.Firstly,the structure design of Bi³⁺ion substituted material was carried out,and the low melting point oxide Bi₂O₃ was introduced.The results show that Bi³⁺ion substitution can effectively reduce the sintering temperature of YIG to 970℃,but the ferromagnetic resonance line width of the sample is large（～400 Oe）.Subsequently,the iron-deficiency formula was used,and it was found that the introduction of a certain amount of iron deficiency reduced the ferromagnetic resonance line width by inhibiting the transformation from Fe³⁺to Fe²⁺,and meanwhile,increased the saturation magnetization intensity.Next,in order to further reduce the sintering temperature of the material,a technical scheme of Bi³⁺-Li⁺-V⁵⁺multi-ion substitution was designed.The results show that the multicomponent ion substitution can further activate the lattice and reduce the sintering temperature to 930℃.In addition,in order to regulate the loss parameters of YIG,YIG ferrite substituted by multiple ions under certain iron deficiency was prepared.The results show that,when the sintering temperature is 900℃,the substitution quantity x=0.03,the electromagnetic performance of YIG material is greatly improved:the saturation magnetization intensity is about 1900 Gs,and the ferromagnetic resonance line width is about 200Oe.Finally,based on the electromagnetic theory of circulator and working principle of YIG ferrite materials in this study,using three-dimensional electromagnetic simulation software HFSS to designe the x-band circulator,then by changing the material and structure parameters,makig the circulator in x-band within the scope of the return loss and isolation are less than -20 dB,transmission loss is greater than 0.5 dB,VSWR is less than 1.23,and the relative bandwidth is more than 30%.So that the practical application value of the low temperature sintered ferrite material is verified.