Investigations On The Low Loss YALIG Ferrites And Their Applications On Circulator

Gyromagnetic ferrite material having gyromagnetic properties was widely used in microwave devices, and yttrium iron garnet(YIG) ferrite applies to the lower microwave band due to its extremely narrow ferromagnetic resonance linewidth. The thesis mainly studied Yttrium Aluminum Garnet(YAl IG) material based on substitute a partial Fe3+ by Al3+. YAl IG possess low saturation magnetization and narrow ferromagnetic resonance linewidth primarily apply to lower microwave band. In this thesis, using solid-phase sintering process prepared YAl IG, analysed the way of YIG ion substitution, studied the influence of the parameter x of iron deficiency on Y3Al0.33Fe4.65-x Mn0.02O12(x=0~0.15) material of electromagnetic property, The mainly refer to saturation magnetization 4πMs and ferromagnetic resonance line width ΔH. Then used calcium ions and zirconium ions substituted reduce the ΔH of material, prepared the Y3-y Cay Al0.33Fe4.6-y Zry Mn0.02O12(y=0.2~0.35) material, finally adjust the amount of aluminum ions prepared Y2.7Ca0.3Alx Fe4.63-x Zr0.3Mn0.02O12(x=0.4~0.7) materials. Experimental results show that the appropriate iron deficiency have contributed to improve the electromagnetic properties of the YAl IG material, The more the amount of iron deficiency, a higher sintering temperatures in order to make the material more dense, achieve better electromagnetic properties in the amount of 0.05 iron deficiency. using the zirconium ions replace can increase 4πMs and decrease ferromagnetic resonance linewidth of material, calcium zirconium replacement level of 0.3, YAl IG get smaller ferromagnetic resonance linewidth. By changing the substitution of aluminum ions, calcium zirconium ions and aluminum ions substitution will further reduce the resonance line width ΔH of materials, In the aluminum content of 0.4 to prepare the ferrite materials of saturation magnetization of about 1200 Gs and smaller ferromagnetic resonance linewidth. Proved the YIG replaced by aluminum ions can reduce the saturation magnetization and ferromagnetic resonance line width. During ion substitution, the sintering temperature should be appropriately changed in order to find the best sintering temperature, this can lead the materials more denser, better performance. Finally, according to the test parameters of the material, the thesis used the prepared YAl IG material design stripline circulator, Were designed disc junction circulator and double-Y junction circulator, Comparative results double-Y junction circulator has better performance and smaller size, produced the samples depending on the design of the double-Y junction circulator. testing the S parameters of the circulator with a vector network analyzer, confirm the reliability of the designed circulator, and validation the YAl IG have good performance and practicality.