The Research Of High Performance Y-type Hexaferrite And Its Application

The rapid development of electronic information industry request that rf perceptual component shouid be smaller and integreated. The high frequency system request the electronic components used in GHz frequency band, and the chip miniaturization of the component required the material which is sintered under 900 ℃. The natural resonance frequency of Y-type barium ferrite is extremely high, so its cut-off frequency can be 5.7 GHz in theoretically. It shows good magnetic property and rf application in GHz spectrum. At the same time, the conventional sintering temperature of Y-type barium ferrite is 1200 ℃, therfor reducing its sintering temperature and improving the performance by ion doping must be urgent.In terms of materials, Y-type barium ferrite materials was studied to obtain low temperature sintered Co2 Y ferrite materials which have high performance. We prepared Co2 Y ferrite samples in the traditional solid-state method to study the effects of sintering temperature on the properties of ceramic materials. Through the analysis of the mearsurement results, the best sintering temperature shouid be 1150 ℃. Then we replace Ba2+ ions with Sr2+ ions, but its smaller ionic radius lead to mismatch in lattice. When the amount of doping Sr2+ ions is more than 75%(mole ratio), not only affects the Y phase formation, also leads to rapid increasing of saturation magnetization and coercivity. The study of Ba2Co2-xZnxFe11AlO22 compound shows that the samples get higher staturation magnetization and initial permeability when Zn2+ ions increase. The Co2 Y doping Bi3+ ion(Ba2-xBixCo2+xFe12-xO22) was researched to reduce the sintering temperature of material. When x<0.2, the doped Bi3+ ions can effectively reduce the sintering temperature, but if the x≥0.2,it will result in too much material of mixed phase. Finally, Ba2+ ions were replaced by Bi3+ ions and Co2+ ions are replaced by Cu2+ ion to reduce sintering temperature of the samples, and investigate microscopic characteristic and basic magnetism performance which are changing with doping of Ni2+ ion. In conclusion, the sample which was calcinated at 900℃ forms common phase and microstructure; the addition of Ni2+ ions make for the increase of permeability.Microwave ferrite circulator is an important microwave ferrite devices to saparate the signals in different frequency in microwave communication system. We respectively design microstrip circulator for X band and Ku band. The simulation results show that insertion loss is less than 0.5 dB, return loss and isolation is more than 15 d B for single Y-junction microstrip circulator based on Co2 Y in 8 ~ 12 GHz; insertion loss is less than 2 dB, return loss and isolation is more than 15 dB for single Y-junction microstrip circulator based on Co2 Y in 13 ~ 17 GHz; insertion loss is less than 0.5 dB, return loss and isolation is more than 15 dB for double Y-junction microstrip circulator based on Co2 Y in 12 ~ 17 GHz; insertion loss is less than 0.5 dB, return loss and isolation is more than 20 dB for single Y-junction microstrip circulator based on YIG in 12 ~ 17 GHz;insertion loss is less than 2 dB, return loss and isolation is more than 15 dB for single Y-junction microstrip circulator based on Co2 Y in 21~ 23 GHz Finally single Y-junction microstrip circulator with the material Ba2Co2-xZnxFe11AlO22 was produced, and the test results are analyzed.