Preparation Of Yttrium Iron Garnet Ferrite With High Dielectric Constant And Design Of Microwave Devices

With the continuous development of electronic devices towards miniaturization,high frequency and integration,the development of high-frequency magnetic components has become an important factor restricting integration.Based on the background and demand,soft magnetic granular film with good high-frequency characteristics has become a research hotspot.It can maintain high permeability and high cut-off frequency at the same time.Once of the potential applications is electromagnetic thin film noise suppressor.This thesis mainly studies the preparation process and performance characterization of NiFe YIG granular film,analyzes the influence trend of different process conditions on the high-frequency performance of soft magnetic granular film,and makes corresponding analysis combined with the experimental conditions.NiFe-YIG composite target was prepared by pasting YIG patch on NiFe target runway with silver paste.NiFe-YIG granular film samples were prepared by RF magnetron sputtering.The effects of film composition and preparation process,such as RF sputtering power and sputtering pressure,on the properties of film sample were analyzed and studied.It is found that in the(Ni80Fe20)×(Y3Fe5O12)1-x granular film,when x ? 0.641,the sputtering power is 70 W,the sputtering pressure is 0.8 Pa,and the film thickness is 100 nm,the granular film has better soft magnetic properties and high frequency properties.The saturation magnetization is 9.15 kGs and the coercivity Hc=22 Oe can be obtained by characterization;The resonance frequency is about 1.8 GHz;Through the ferromagnetic resonance characterization,it can be seen that the resonance field Hres=1403 Oe and linewidth ?H=133 Oe under the condition of frequency 10 GHz;The resistivity 188 ??·cm is measured by four probe method.After exploring the regulation of experimental process conditions on the properties of the film,the electromagnetic noise effect of magnetic film placed on microstrip line is simulated and analyzed by HFSS finite element simulation software,The demagnetization factors in all directions of the three-dimensional size change of the film are calculated by theoretical formula,and the magnetic spectrum under the condition of corresponding size is calculated,The simulation results show that the variation of the electromagnetic noise suppression effect of the thin film with the three-dimensional size of the thin film is same as that of the magnetic spectrum with three-dimensional size,indicating that ferromagnetic resonance is the main loss mechanism of the magnetic thin film for noise suppression.