Research On Ferrite Tape Casting Technology And Application Of X-band Microstrip Circulator

X-band (8GHz?12GHz) ferrite circulators have many advantages, such as small size, light weight, good consistency, etc., which plays an important role in the phased array radar and communication systems.Microwave YIG ferrite is an fundamental gyromagnetic material of modern electronic information industry, and it is a typical material for X-band ferrite devices and is widely used in other microwave ferrite devices.Based on YIG ferrite materials, this paper explores the thick film tape casting process and the simulation of ferrite microstrip circulator of X-band. The critical processes of YIG ferrite preparation and sintering were studied by using oxide ceramic method. The samples were characterized by XRD, SEM, VSM and the test system of narrow ferromagnetic resonance linewidth. The result shows that the saturation magnetization 4?Ms and Bs are increasing by doping of Sn4+, B, increases first and then decrease, both H, and ferromagnetic resonance line width decrease.The best magnetization can be obtained at sintering temperature of 1380?. The saturation magnetization 47?Ms and the density can be reduced by doping of V5+, both Bs and Br decrese, while H, increases. There is adhesion after sintering and the best magnetic properties are obtained at sintering temperature of 1360?.Several key factors influencing the tape casting process were discussed for the material formulation for X-band ferrite circulators The result shows that the saturation magnetization Ms and the density increase with the increasing of the pressing time.Only the proper viscosity can be cast, and with the increase ratio of alcohol, the saturation magnetization Ms and density are increasing, and the shrinkage rate tends to decrease. The number of layers of the thick film has a slight influence on the property.The suitable binder removal time is 4h and the temperature is 350?. The above parameters can be flexibly adjusted when combined with actual use.Finally, based on the YIG ferrite thick film material discussed above, the three-dimensional electromagnetic field simulation model was established by using Ansoft HFSS simulation software to analyze and simulate the X-band microstrip circulator. The simulation result shows that the return loss and isolation of single Y-junction are more than 20dB and the VSWR is less than 1.20 in the 8GHz ?11GHz frequency band. In the 8GHz ?10Hz band,the insertion loss is less than 2dB In the frequency band of 8 ?12GHz,the return loss and isolation of double Y-junction are more than 20dB, the insertion loss is less than 0.5dB, and the VSWR is less than 1.20 in the frequency band of 7.5GHz?12.5GHz, and 5GHz bandwidth is successfully achieved,besides, the size of the design becomes smaller. By comparing the thickness of ferrite substrate, the center radius of ferrite, the magnetic field strength and the height of the cavity, the optimal simulation parameters based on double Y-junction ferrite microstrip circulator are obtained with the thickness of ferrite substrate is 1.0mm, the center radius of ferrite is 3.1mm, magnetic field strength is 14000e, cavity height is 14mm.