Research And Preparation Of YIG Ferrite Used In Magnetically Tunable Band-pass Filter

YIG ferrite as the most important part in the modern electronic information materials plays a meaningful role for the miniaturization and integration of the microwave devices. YIG ferrite is gyromagnetic material. It could make the filter magnetic tunable. This paper study the different kinds of YIG ferrite with different microstructure and electromagnetic properties and the magnetic tunable band-pass microwave filter with these YIG ferrites as substrate in ADS and HFSS. This paper mainly includes two parts: The conventional ceramic process preparation of Yttrium iron garnet ferrite and the simulation of the band-pass filter with substrate of YIG ferrites.Firstly, this paper study the crystal structure and the ionic replacement and analyse the main parameters of the performance and influence. Then this paper study the basic parameters during the process with the conventional ceramic method, it includes the influence of Fe-short content and the pressure during the conventional ceramic. And the effects of Al3+ and Mn2+ addition on the properties of YIG. The result of the experiments shows that the optimum Fe content is 0.05, the optimum forming pressure is 5Mpa. The saturation magnetization of YIG ferrite is decreased by the increasing of Al3+. Under the condition of the certain Al3+ ion content, the trace Mn2+ doping could decrease the dielectric loss of YIG ferrite. But it couldn't make the relative dielectric constant of the YIG ferrite change.Then this paper study for the theory of the design for the parallel coupled microstrip band-pass filter and the magnetic tunability. And get a summary of the design principle of microstrip filter with the substrate of YIG ferrites. At first this paper design a band-pass filter with ADS. Then we redesign a band-pass with the YIG ferrites in HFSS and not only studys the possibility of the magnetic tunable band-pass filter with the YIG ferrites but also the effects of the filter with substrate of the different kinds of the YIG ferrites with different relative dielectric constant, dielectric loss tangent and saturation magnetization. The result of the experiments shows that the central frequency of the band-pass filter goes to the high frequency with the increasing of the applied bias magnetic field.