Research Of Preparing BST Ferroelectric Phase Shifter And High Frequency Permittivity Testing

For its ferroelectric, piezoelectricity and thermoelectricity performance, BST ferroelectric ceramic material become a pop research in home and oversea due to its high permittivity, high tunable ability and low electronic loss at the room temperature;but until now, there is no uniform and ripe criterion and technique, so the research of the method and technique of testing the permittivity at high frequency has very creative meaning and bright foreground.The relationship between the physical and the composition of the material and crystal lattice structure of the BST material was researched in this essay based on the dielectronic theory and the whole process. SEM, XRD and DSC analysis of the BST sample shows the composition, process condition and process controllability condition can be optimized, as well as the BST material's agglomeration curve and technics. XRD and SEM analysis presented the jarless composition and good crystallization of BST sample and the crystal diameter was hundreds nanometer. The BST ceramic sample was prepared using sol-gol method adulterating MgO and Bi₂O₃. The BST/MgO sample's permittivity and dielectronic loss was tested using VNA(Vector Network Analyzer) at the 8.2-12.4GHz and 2.4-18.0GHz,and the relation curve between the frequency and permittivity was given.The high frequency microwave test method and technic was studied in this essay based on the microwave theory and technic. The issues in the testing method and theory and the error that brought in by the instrument and the testing result was stressed and discussed. The relationship between the thickness and the frequency and the permittivity, showed the thickness of the sample was not as good as thin and it has the best thickness at every frequency and every permittivity, and the corresponding thickness at different frequency and different permittivity was presented.Using the translation/reflection method, the multi-value character and syntony character was discussed. The simulation result showed the relationship between the frequency, the thickness and the permittivity of the BST sample.