Research On Low-frequency Properties And Modification Of Barium Strontium Titanate Oxide Ceramics For Tunable Microwave Application

As an elementary unit applied in microwave phased array radar antennas with excellent performances, ferroelectric phase shifter has brought a complete revolution. The advantages of BSTO electro-optic phase shifters over ferrite phase shifters are higher power-handling capacity, faster phase shifter speed, lower driven power, low insert losses, smaller and light structure. So a large magnitude of human and material resources have been put into the relative researches in many countries. The related research works presently focus on how to decrease the dielectric loss of the material and maintain a relatively high tunability.This project"high-performance compound ferroelectric material"was funded by National Natural Science Foundation of China and research on low-frequncy properties of Barium Strontium Titanate mixed with ZnAl₂O₃, MgTiO₃ and Mg_0.95Ca_0.05TiO₃.Ferroelectric material employed in ferroelectric phase shifter must have these basic requirements: moderate dielectric constantεr , low dielectric loses (tanδ) and high dielectric constant tunability.The main research points include:1. Effects of different Ba / Sr contents Ba_1-xSr_xTiO₃(x=0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8) on Curie temperature,dielectric properties and the tunability changes with temperature changed.2. Low-loss microwave ceramics including ZnAl₂O₃, MgTiO₃ and Mg_0.95Ca_0.05TiO₃ have been mixed with appropriate Ba_1-xSr_xTiO₃ (0