Low-temperature Sintering Nicuzn Gyromagnetic Ferrite Materials And Devices Research

With the continuous development of technology for passive integrated and multichip package, the planar chip device is becoming an important researching direction. Presently, the LTCC (Low temperature Co-fired Ceramic) technology is used as a superiority way to produce miniature microwave ferrite devices and this technology demands low temperature co-fired gyromagnetic ferrite material to support it.In this dissertation, the low temperature co-fired of NiCuZn gyromagnetic ferrite material is the main thesis. After the experiments and theoretical analysis, the effects of composition, addition and low-temperature sintering of NiCuZn materials have been investigated. It's expected to become the gyromagnetic ferrite substrates to produce the microwave ferrite circulator.First, the effects of compositions, sintering temperatures and additions of Bi2O3 were investigated on the microstructures and gyromagnetic properties of NiCuZn ferrites. The microstructures of sintered ferrites were learned by SEM and XRD. The gyromagnetic properties are saturation magnetization, ferromagnetic resonance line width, dielectric loss. At last, the Ni0.7Cu0.05Zn0.25Fe1.96O4 ferrites were prepared, adding 3wt% Bi2O3, calcining at 900℃for 3h and sintering at 900℃for 5h, with the Ms>300kA/m,△H<20kA/m and tgδε≈6×10-4.Second, Using the prepared NiCuZn gyromagnetic parameters,the Ansoft-HFSS was adopted to creating model and emulating the electro-magnetic field for X-band(8~12G) circulator. Lastly, the prepared NiCuZn gyromagnetic ferrite substrates were chosen to produce the X-band micro-strip line circulator by silk screen. The testing results were:insert loss≤1.5dB, isolation≥15dB, VSWR≤1.3. It was different from the forecast because of the manufacture and test error.